Ignition-suppressing lithium secondary battery

Abstract

The present invention relates to a lithium secondary battery having an ignition suppressing structure, and more specifically, to a lithium secondary battery having a structure capable of suppressing an ignition phenomenon.

Description

[Technical Field]

[0001] The present invention relates to a lithium secondary battery having an ignition suppression structure.

[0002] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0015670, dated February 7, 2022, and all contents disclosed in the documents of said Korean patent application are incorporated herein by reference. [Background technology]

[0003] A lithium secondary battery typically comprises a battery cell including a positive electrode, a negative electrode, an electrolyte, and a separator. A pouch cell, which is one type of battery cell, has a configuration in which an electrode assembly, in which a plurality of unit cells each including a positive electrode, a negative electrode, and a separator are stacked, is housed in a pouch-shaped battery case together with an electrolyte.

[0004] Figure 1 shows the structure of a conventional pouch cell. Referring to Figure 1(a), a lithium secondary battery includes an electrode lead 30, an insulating film 20, an electrode assembly 10, and a battery case 40. The battery case 40 includes a receiving portion Ac' in which the electrode assembly 10 is received, and an edge portion Ed' extending laterally along the edge of the receiving portion Ac'.

[0005] The pouch cell has a configuration in which an electrode assembly 10 is housed in a pouch-shaped battery case 40. The electrode assembly 10 refers to a stack of multiple electrode plates, and the electrode plates are composed of negative and positive electrode plates. That is, the electrode assembly 10 housed in the pouch-shaped battery case 40 is a stack of alternately stacked positive and negative electrode plates. The positive and negative electrode plates are separated by a separator. Electrode tabs 11 are extended from or connected to the electrode plates according to their polarities. Electrode leads 30 are connected to the electrode tabs 11. The electrode tabs 11 and electrode leads 30 are joined by ultrasonic welding or the like.

[0006] The insulating film 20 is attached onto the electrode lead 30 to seal and insulate the electrode lead 30 and the battery case 40, and is interposed between the joint of the upper battery case 41 and the lower battery case 42 when the joints of the upper battery case 41 and the lower battery case 42 are joined and sealed.

[0007] 1(b), when the upper battery case 41 and the lower battery case 42 are joined together, the electrode leads 30 connected to the electrode tabs 11 protrude outside the battery case 40. In other words, the upper battery case 41 and the lower battery case 42 seal the electrode assembly 10, thereby protecting it from the outside.

[0008] Meanwhile, since the battery case 40 acts as a heat insulator, the heat generated in the electrode assembly 10 inside may not be released to the outside, which may cause the lithium secondary battery to ignite due to overheating. Specifically, the heat generated in each unit cell is superimposed, causing the temperature inside the battery cell to rise and the inside of the battery cell to overheat.

[0009] Generally, a lithium secondary battery includes multiple stacked electrode plates, so heat is concentrated at the center of the electrode assembly 10, causing the temperature at the center to rise exponentially. When the inside of the lithium secondary battery reaches a high temperature as described above, thermal runaway occurs in the positive electrode, and the generated heat can cause the lithium secondary battery to explode.

[0010] In recent years, there has been a trend toward increasing the energy density of lithium secondary batteries, and therefore, a method capable of suppressing the above-mentioned overheating phenomenon caused by the superposition of heat generated in the unit cells is required. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] Korean Patent Publication No. 10-2019-0024709 Summary of the Invention [Problem to be solved by the invention]

[0012] The present invention aims to eliminate the overheating phenomenon caused by the superposition of heat generated in a plurality of unit cells. [Means for solving the problem]

[0013] According to the present invention, there is provided a lithium secondary battery with an ignition suppression structure, comprising: an electrode assembly including a first electrode part including a unit cell, a second electrode part including a unit cell, and a heat dissipation part including a heat dissipation member; and a battery case including an upper battery case and a lower battery case, the battery case including a receiving part that receives the electrode assembly and a joint part that is extended along an edge of the receiving part, wherein the heat dissipation part is interposed between the first electrode part and the second electrode part.

[0014] Specifically, each of the first electrode portion and the second electrode portion may include at least one unit cell.

[0015] More specifically, the number of unit cells included in the first electrode portion and the number of unit cells included in the second electrode portion may be the same.

[0016] Specifically, a separation film may be interposed between the heat dissipation part and the first electrode part, and between the heat dissipation part and the second electrode part.

[0017] The heat dissipation unit may include a plurality of heat dissipation members, and a separation film may be interposed between each of the heat dissipation members.

[0018] Preferably, the heat dissipation member may contain at least one of copper, aluminum, nickel, a copper alloy, a nickel alloy, titanium, stainless steel (SUS), and carbon.

[0019] Specifically, the unit cell may include a positive electrode plate including a positive electrode current collector, a positive electrode tab drawn from one end of the positive electrode current collector, and a positive electrode mixture coated on a surface of the positive electrode current collector; a negative electrode plate including a negative electrode current collector, a negative electrode tab drawn from one end of the negative electrode current collector, and a negative electrode mixture coated on a surface of the negative electrode current collector; and a separator interposed between the positive electrode plate and the negative electrode plate.

[0020] Specifically, the heat dissipation member may have a plate shape, and the length and width of the heat dissipation member may not exceed the length and width of the positive electrode current collector or the negative electrode current collector.

[0021] The heat dissipation member may further include a heat dissipation tab extending from a position corresponding to one of the positive electrode tab and the negative electrode tab.

[0022] In addition, the total thickness of the heat dissipation member included in the heat dissipation unit may be greater than the thickness of the positive electrode current collector or the negative electrode current collector.

[0023] In addition, the total thickness of the heat dissipation member included in the heat dissipation unit may be 8 times or less the thickness of the positive electrode current collector.

[0024] Meanwhile, the positive electrode tab may be connected to a heat dissipation tab at a position corresponding to the positive electrode tab, and the negative electrode tab may be connected to a heat dissipation tab at a position corresponding to the negative electrode tab.

[0025] According to another embodiment, the heat dissipation member may further include a heat dissipation fin extending from one end where the positive electrode tab and the negative electrode tab are not located.

[0026] Specifically, the heat dissipation fins may be interposed between the joint portion of the upper battery case and the joint portion of the lower battery case without exceeding the joint portion of the battery case. [Effects of the Invention]

[0027] According to the present invention, even if high temperature heat is generated locally in the electrode assembly inside the battery cell, overheating and ignition of the lithium secondary battery can be suppressed. [Brief explanation of the drawings]

[0028] [Figure 1] 1 shows the structure of a conventional pouch cell. [Figure 2] 1 shows the configuration of a lithium secondary battery according to a first embodiment of the present invention. [Figure 3] 1 shows the configuration of a unit cell of the present invention. [Figure 4] 1 illustrates an example of the configuration of a heat dissipation unit according to the present invention. [Figure 5] 10 shows the configuration of an electrode assembly of a lithium secondary battery according to a second embodiment of the present invention. [Figure 6] 10 shows the configuration of a heat dissipation part of a lithium secondary battery according to a third embodiment of the present invention. [Figure 7] 10 shows the configuration of a lithium secondary battery according to a third embodiment of the present invention. [Figure 8] 10 is a partial cross-sectional view of a lithium secondary battery according to a third embodiment of the present invention. [Figure 9] 1 shows the configuration of an electrode assembly stack according to Examples 1 to 3 of the present invention. [Figure 10] 1 shows the configurations of electrode assembly stacks according to Comparative Examples 1 and 2 of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0029] The detailed configuration of the present invention will be described in detail below with reference to the accompanying drawings and various embodiments. The embodiments described below are shown as examples to help understand the present invention, and the accompanying drawings are not drawn to actual scale to help understand the invention, and the dimensions of some components may be exaggerated.

[0030] Because the present invention can be modified in various ways and can have various forms, specific embodiments are shown by way of example in the drawings and described in detail herein, but it is not intended to limit the invention to the particular forms disclosed, and it should be understood that the invention includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

[0031] The lithium secondary battery of the present invention includes an electrode assembly including a plurality of unit cells, and a battery case that houses the electrode assembly.

[0032] 2 and 3 show the configuration of a lithium secondary battery according to a first embodiment of the present invention, and FIGS. 4 and 5 show the configuration of a lithium secondary battery according to a second embodiment of the present invention.

[0033] The present invention will now be described with reference to the above drawings.

[0034] (First embodiment) FIG. 2 shows the configuration of a lithium secondary battery according to a first embodiment of the present invention.

[0035] 2, it can be seen that the battery case includes a receiving portion capable of receiving the electrode assembly 100, and has a structure in which the electrode assembly 100 can be inserted into the receiving portion and sealed. More specifically, the battery case includes an upper battery case 210 that covers the upper part of the electrode assembly 100, and a lower battery case 220 that covers the lower part of the electrode assembly 100.

[0036] At least one of the upper battery case 210 and the lower battery case 220 may include a receiving portion capable of completely receiving the electrode assembly 100 therein.

[0037] The upper battery case 210 and the lower battery case 220 may be manufactured integrally or separately, which can be adjusted according to manufacturing purposes.

[0038] In the present invention, an example has been given in which each of the upper battery case 210 and the lower battery case 220 includes a housing portion.

[0039] The electrode assembly 100 includes a first electrode portion including a plurality of unit cells 110, a second electrode portion including a plurality of unit cells 110, and a heat dissipation portion interposed between the first electrode portion and the second electrode portion and including a heat dissipation member 130.

[0040] Referring to FIG. 2, it can be seen that the first electrode portion located on the upper part of the heat dissipation portion includes a plurality of stacked unit cells 110, and the second electrode portion located on the lower part of the heat dissipation portion also includes a plurality of stacked unit cells 110.

[0041] The first electrode portion and the second electrode portion each need to include at least one unit cell 110, and preferably, the number of unit cells 110 included in the first electrode portion and the second electrode portion should be the same.

[0042] That is, the first electrode unit and the second electrode unit may have a symmetrical structure with respect to the heat dissipation unit. The more symmetrical the first electrode unit and the second electrode unit are, the closer the heat dissipation unit may be to the center of the electrode assembly 100 in the thickness direction, and the heat dissipation unit located at the center of the electrode assembly 100 may evenly absorb heat generated in the upper first electrode unit and the lower second electrode unit, facilitating heat dissipation to the outside. If the number of unit cells 110 included in the first electrode unit and the second electrode unit is significantly different and the first electrode unit and the second electrode unit cannot have a symmetrical structure with the heat dissipation unit between them, the heat generated in each electrode unit may be biased to one side, and the heat dissipation unit may not be able to sufficiently absorb the heat.

[0043] The first electrode unit, the heat dissipation unit, and the second electrode unit are sequentially stacked to form one electrode assembly 100, and at this time, each component is preferably electrically separated by a separation film 120. Specifically, the separation film 120 is preferably interposed between the first electrode unit and the heat dissipation unit. In addition, the separation film 120 is preferably interposed between the second electrode unit and the heat dissipation unit.

[0044] The unit cells 110 included in each of the first and second electrode parts include a positive electrode plate 111 a, a negative electrode plate 111 b, and a separator 112 .

[0045] FIG. 3 shows the configuration of a unit cell 110 of the present invention.

[0046] Referring to FIG. 3, the unit cell 110 is mainly composed of an electrode plate and a separator 112 .

[0047] The electrode plate includes an electrode current collector, an electrode mixture coated on the electrode current collector, and an electrode tab drawn out from one end of the electrode current collector.

[0048] The electrode plates, electrode current collectors, electrode tabs, and electrode mixtures can be divided into two types depending on their polarities. Specifically, the electrode mixture is composed of a positive electrode mixture 111a2 containing a positive electrode active material and a negative electrode mixture 111b2 containing a negative electrode active material. The electrode current collectors are composed of a positive electrode current collector 111a1 and a negative electrode current collector 111b1 that is symmetrical to the positive electrode current collector 111a1 with respect to the separator 112. The electrode tabs are composed of a positive electrode tab 111a3 drawn from the positive electrode current collector 111a1 and a negative electrode tab 111b3 drawn from the negative electrode current collector 111b1.

[0049] The electrode plate includes a positive electrode plate 111a including a positive electrode current collector 111a1, a positive electrode tab 111a3 drawn from one end of the positive electrode current collector 111a1, and a positive electrode mixture 111a2 coated on the surface of the positive electrode current collector 111a1, and a negative electrode plate 111b including a negative electrode current collector 111b1, a negative electrode tab 111b3 drawn from one end of the negative electrode current collector 111b1, and a negative electrode mixture 111b2 coated on the surface of the negative electrode current collector 111b1.

[0050] The positive electrode plate 111a and the negative electrode plate 111b may have different thicknesses depending on the required capacity of the lithium secondary battery, but the positive electrode plate 111a and the negative electrode plate 111b used in one lithium secondary battery preferably have the same thickness. Furthermore, the positive electrode current collector 111a1 included in the positive electrode plate 111a and the negative electrode current collector 111b1 included in the negative electrode plate 111b may have the same thickness.

[0051] The positive electrode mixture 111a2 may be coated on one or both surfaces of the positive electrode current collector 111a1, but this is not particularly limited in the present invention.

[0052] The positive electrode mixture 111a2 may preferably include a positive electrode active material, a conductive material, a binder, etc., and any positive electrode material commonly used in the technical field of lithium secondary batteries may be used for the positive electrode mixture 111a2.

[0053] The positive electrode current collector 111a1 provides a path for electron movement, releases heat generated inside to the outside, and also serves as a support for maintaining the shape of the electrode.

[0054] The positive electrode current collector 111a1 may be made of any material commonly used in the field of lithium secondary batteries. For example, the positive electrode current collector 111a1 may include aluminum.

[0055] The thickness of the positive electrode current collector 111a1 is preferably 1 μm to 20 μm.

[0056] It is preferable that the positive electrode tab 111a3 drawn out from one end of the positive electrode current collector 111a1 is not coated with the positive electrode mixture 111a2.

[0057] The negative electrode mixture 111b2 may be coated on one or both surfaces of the negative electrode current collector 111b1, but this is not particularly limited in the present invention.

[0058] The negative electrode mixture 111b2 may preferably include a negative electrode active material, a conductive material, a binder, etc., and any negative electrode material commonly used in the technical field of lithium secondary batteries may be used for the negative electrode mixture 111b2.

[0059] The negative electrode current collector 111b1 provides a path for electron movement, releases heat generated inside to the outside, and also serves as a support for maintaining the shape of the electrode.

[0060] The negative electrode current collector 111b1 may be made of any material commonly used in the field of lithium secondary batteries. For example, the negative electrode current collector 111b1 may include copper.

[0061] The thickness of the negative electrode current collector 111b1 is preferably 1 μm to 20 μm.

[0062] It is preferable that the negative electrode tab 111b3 drawn out from one end of the negative electrode current collector 111b1 is not coated with the negative electrode mixture 111b2.

[0063] In the present invention, the positive electrode tab 111a3 and the negative electrode tab 111b3 must be prevented from overlapping each other in the vertical direction, because the positive electrode tab 111a3 bundles the positive electrode tabs 111a3 and the negative electrode tab 111b3 bundles the negative electrode tabs 111b3, and they are separated and connected to the positive electrode lead and the negative electrode lead, respectively.

[0064] The positive electrode tab 111a3 and the negative electrode tab 111b3 may be formed and positioned in the same direction or in opposite directions in the electrode assembly 100, but there is no need to be particularly limited thereto. For ease of understanding, it is assumed in the present invention that the positive electrode tab 111a3 and the negative electrode tab 111b3 are formed to face the same direction in the electrode assembly 100.

[0065] The separators 112 and 120 of the present invention may be any separators 112 and 120 used in the technical field of lithium secondary batteries, and the present invention is not particularly limited thereto.

[0066] The electrode assembly 100 of the present invention is characterized by having a structure that allows heat generated inside to be released to the outside via a heat dissipation portion.

[0067] Referring to FIG. 2, the heat dissipation part includes a heat dissipation member 130 having a plate-like shape.

[0068] The heat dissipation member 130 is made of a material that can effectively absorb heat, and serves to absorb heat generated within the electrode assembly 100 sealed by the battery case and smoothly dissipate the absorbed heat to the outside.

[0069] The heat dissipation member 130 preferably includes at least one of copper, aluminum, nickel, a copper alloy, a nickel alloy, titanium, stainless steel (SUS), and carbon.

[0070] It is preferable that the length and width of the heat dissipation member 130 does not exceed the length and width of the positive electrode current collector 111a1 and the negative electrode current collector 111b1 included in the first electrode portion and the second electrode portion, and more preferably, the length and width of the heat dissipation member 130 can match the length and width of the positive electrode current collector 111a1 and the negative electrode current collector 111b1.

[0071] Preferably, the single heat dissipation member 130 may further include a heat dissipation tab 131 drawn out from a position corresponding to one of the positive electrode tab 111a3 and the negative electrode tab 111b3.

[0072] The heat dissipation tab 131 is coupled to the positive electrode tab 111a3 or the negative electrode tab 111b3 and serves to dissipate the heat absorbed by the heat dissipation member 130 to the outside.

[0073] The thickness of the heat dissipation member 130 is preferably thicker than the thickness of the positive electrode current collector 111a1 in order to absorb more heat generated within the electrode assembly 100. If the thickness of the heat dissipation member 130 is not sufficiently thick, it may not be possible to absorb or store enough heat internally. The reason why the thickness of the positive electrode current collector 111a1 is determined based on the thickness of the heat dissipation member 130 is that relatively more heat is generated from the positive electrode plate 111a than from the negative electrode plate 111b within the unit cell 110.

[0074] (Second embodiment) In the lithium secondary battery of the present invention, the heat dissipation section may include a plurality of heat dissipation members 130 .

[0075] FIG. 4 shows an example of the configuration of the heat dissipation part of the present invention.

[0076] 4(a) shows the heat dissipation part of the lithium secondary battery according to the first embodiment, and it can be seen that the heat dissipation part uses one heat dissipation member 130. In this case, the separator 120 is provided on both sides of the heat dissipation member 130.

[0077] 4(b), it can be seen that two heat dissipation members 130 are stacked in the heat dissipation section. It can be seen that a separator 120 is provided between the heat dissipation members 130 and on the outer surface of the heat dissipation members 130. It can also be seen that heat dissipation tabs 131 extend from different positions in each heat dissipation member 130. In this case, one heat dissipation tab 131 is connected to the negative electrode tab 111b3, and the other heat dissipation tab 131 is connected to the positive electrode tab 111a3.

[0078] 4(c), it can be seen that a plurality of heat dissipation members 130 are stacked in the heat dissipation section. Separators 120 are interposed between the respective heat dissipation members 130 to electrically separate the heat dissipation members 130. In this case, the plurality of heat dissipation tabs 131 may be formed in the same number as the number of the heat dissipation members 130, and the heat dissipation tabs 131 are divided into two positions corresponding to the positive electrode tab 111a3 and the negative electrode tab 111b3 and are drawn out from the heat dissipation members 130.

[0079] As described above, the heat dissipation unit may include a plurality of heat dissipation members 130. However, the total thickness of the heat dissipation members 130 included in the heat dissipation unit should not exceed eight times the thickness of the positive electrode current collector 111a1. Preferably, the total thickness of the heat dissipation members 130 included in the heat dissipation unit is two to eight times the thickness of the positive electrode current collector 111a1. If the total thickness of the heat dissipation members 130 is less than twice the thickness of the positive electrode current collector 111a1, it may be difficult to sufficiently absorb the heat generated in the positive electrode plate 111a. Furthermore, if the total thickness of the heat dissipation members 130 exceeds eight times the thickness of the positive electrode current collector 111a1, a problem of reduced energy density of the lithium secondary battery may occur.

[0080] Furthermore, the total thickness of the heat dissipation member 130 included in the heat dissipation unit is preferably 40% or less of the total thickness of the positive electrode current collector 111a1 and the negative electrode current collector 111b1 included in the first electrode unit and the second electrode unit. More preferably, the total thickness of the heat dissipation member 130 included in the heat dissipation unit is 10% to 40% of the total thickness of the positive electrode current collector 111a1 and the negative electrode current collector 111b1 included in the first electrode unit and the second electrode unit. If the total thickness of the heat dissipation member 130 is less than 10%, the heat absorption effect of the heat dissipation member 130 cannot be sufficiently obtained. If the total thickness exceeds 40%, the heat dissipation member 130 occupies an excessive volume, which may reduce the energy density of the lithium secondary battery.

[0081] FIG. 5 shows the configuration of an electrode assembly 100 of a lithium secondary battery according to a second embodiment of the present invention.

[0082] 5, it can be seen that the heat dissipation unit includes two heat dissipation members 130. Specifically, a separation membrane 120 is interposed between the two heat dissipation members 130, and a separation membrane 120 is attached to each of the heat dissipation members 130 on one side facing outward.

[0083] As described above, the heat dissipation unit of the present invention may include two heat dissipation members 130, but the total thickness of the two heat dissipation members 130 must not exceed eight times the thickness of the positive electrode current collector 111a1. Preferably, the total thickness of the two heat dissipation members 130 included in the heat dissipation unit is two to eight times the thickness of the positive electrode current collector 111a1. More preferably, it is three to six times the thickness of the positive electrode current collector 111a1.

[0084] Furthermore, the total thickness of the two heat dissipation members 130 included in the heat dissipation unit is preferably 40% or less of the total thickness of the positive electrode current collector 111a1 and the negative electrode current collector 111b1 included in the first electrode unit and the second electrode unit, and more preferably 10% to 40% of the total thickness of the positive electrode current collector 111a1 and the negative electrode current collector 111b1 included in the first electrode unit and the second electrode unit.

[0085] That is, in the present invention, the number of heat dissipation members 130 included in the heat dissipation section does not need to be limited, but it is preferable that the range of the total thickness of the heat dissipation members 130 be limited by the thickness of the positive electrode current collector 111a1 or the total thickness of the positive electrode current collector 111a1 and the negative electrode current collector 111b1.

[0086] (Third embodiment) The heat dissipation member 130 of the present invention may further include heat dissipation fins 132 that have the function of dissipating heat generated in the heat dissipation member 130 to the outside.

[0087] FIG. 6 shows the configuration of a heat dissipation part of a lithium secondary battery according to a third embodiment of the present invention.

[0088] 6, it can be seen that the heat dissipation fins 132 are formed extending from one side end of the heat dissipation member 130. The heat dissipation fins 132 may be formed extending along the side of the heat dissipation member 130 as shown in the figure to facilitate heat dissipation to the outside, but are not limited to this. However, if the heat dissipation fins 132 are formed extending along the side of the heat dissipation member 130, there is a risk that the positive electrode tab 111a3 and the negative electrode tab 111b3 included in the unit cell 110 may be electrically connected to each other by the heat dissipation fins 132. Therefore, it is preferable that the heat dissipation fins 132 be formed extending from one side end of the heat dissipation member 130 where the positive electrode tab 111a3 and the negative electrode tab 111b3 are not located. If the heat dissipation member 130 has a heat dissipation tab 131, it is preferable that the heat dissipation fins 132 be formed extending from the other side end where the heat dissipation tab 131 is not located.

[0089] FIG. 7 shows the configuration of a lithium secondary battery according to a third embodiment of the present invention.

[0090] Referring to FIG. 7, it can be seen that the heat dissipating fins 132 are formed by extending from the other end of the side of the heat dissipating material where the heat dissipating tab 131 is not located.

[0091] The heat dissipation fins 132 are drawn out from the heat dissipation member 130 over a wider area than the heat dissipation tabs 131, so that the heat absorbed by the heat dissipation member 130 can be smoothly dissipated to the outside.

[0092] The heat dissipation fins 132 are preferably interposed between the upper battery case 210 and the lower battery case 220 when the electrode assembly 100 is housed in the upper battery case 210 and the lower battery case 220 and the upper battery case 210 and the lower battery case 220 are joined together because the heat dissipation fins 132 are effective in releasing heat to the outside through the joint of the battery cases.

[0093] FIG. 8 is a partial cross-sectional view of a lithium secondary battery according to a third embodiment of the present invention.

[0094] Referring to FIG. 8(a), it can be seen that the heat dissipation fins 132 are interposed between the joint between the upper battery case 210 and the lower battery case 220.

[0095] 8(b), it can be seen that the heat dissipation fins 132 are interposed between the joints of the upper battery case 210 and the lower battery case 220, and the ends of the heat dissipation fins 132 are open to the outside. In the structure shown in FIG. 8(b), heat can be more effectively dissipated through the ends of the heat dissipation fins 132.

[0096] Example 1 An electrode assembly was fabricated by stacking a 15 μm thick negative electrode current collector (copper foil) coated with a negative electrode mixture containing a negative electrode active material (graphite) and a binder (polyvinylidene fluoride), a 15 μm thick positive electrode current collector (aluminum foil) coated with a positive electrode mixture containing a positive electrode active material (LiCoO), a conductive material (carbon black), and a binder (polyvinylidene fluoride), and a separator (porous polyethylene film). A 60 μm thick heat dissipation member (aluminum) was also prepared. The stacked structures were similar to those shown in FIG. 9(a) to fabricate an electrode assembly.

[0097] Then, the heat dissipation tab was combined with the positive electrode tab, and the battery case was covered as shown in FIG. 1 to manufacture a lithium secondary battery.

[0098] <Example 2> Two heat dissipation members (aluminum) each having a thickness of 30 μm were stacked in the same structure as in FIG. 9(b), and the remaining conditions were the same as in Example 1 above to produce a lithium secondary battery.

[0099] Example 3 A lithium secondary battery was manufactured under the same conditions as in Example 1, except that a heat dissipation fin having the structure of FIG. 6 was interposed between the joint between the upper battery case and the lower battery case as shown in FIG. 8(b).

[0100] <Comparative Example 1> A 15 μm thick heat dissipation member (aluminum) was laminated in the same structure as in FIG. 10(a), and the remaining conditions were the same as in Example 1 above to produce a lithium secondary battery.

[0101] <Comparative Example 2> A 60 μm thick heat dissipation member (aluminum) was laminated in the same structure as in FIG. 10(b), and the remaining conditions were the same as in Example 1 above to produce a lithium secondary battery.

[0102] <Experimental example (evaluation of battery heat generation during charging and discharging)> In order to evaluate the performance of the secondary battery according to the present invention, the following experiment was carried out.

[0103] The secondary batteries fabricated in the examples and comparative examples were overcharged, and the surface temperatures of the overcharged secondary batteries were measured. Specifically, after charging to 4.2 V, the charged batteries were overcharged at a constant current of 1 A to 8.4 V. The surface of each secondary battery was photographed with a thermal imaging camera, and the temperature of the secondary battery was measured three times. The average value was calculated and used as the surface temperature of the battery during overcharge.

[0104] The measurement results are shown in Table 1 below.

[0105] [Table 1]

[0106] As shown in Table 1 above, it can be seen that the secondary battery according to the present invention can minimize heat generation during charging and discharging.

[0107] Specifically, referring to Table 1 above, it can be seen that the measured temperatures of the lithium secondary batteries manufactured in Examples 1 to 3 were lower than those of Comparative Examples 1 and 2. In particular, it can be seen that in the case of Example 3, in which a heat dissipation fin configuration was added, the internal temperature of the lithium secondary battery was effectively reduced. Considering the results of Comparative Example 1, it is predicted that the heat dissipation member did not function sufficiently to effectively absorb the heat generated inside and release it to the outside. Considering the results of Comparative Example 2, it is predicted that the applied heat dissipation member did not effectively absorb the heat generated by the entire electrode assembly.

[0108] The present invention has been described in more detail above with reference to the drawings and embodiments, etc. However, the configurations described in the drawings or embodiments in this specification are merely one embodiment of the present invention and do not represent all of the technical ideas of the present invention, so it should be understood that there may be various equivalents and modifications that can replace them at the time of filing this application. [Explanation of symbols]

[0109] 10: (conventional) electrode assembly 11: (conventional) electrode tab 20: (conventional) insulating film 30: (conventional) electrode lead 40: (Conventional) Battery Case 41: (conventional) upper battery case 42: (Conventional) Lower battery case 100: Electrode assembly 110: Unit cell 111a: Positive electrode plate 111a1: Positive electrode current collector 111a2: Positive electrode mixture 111a3: Positive electrode tab 111b: Negative electrode plate 111b1: Negative electrode current collector 111b2: Negative electrode mixture 111b3: Negative electrode tab 112, 120: Separation membrane 130: Heat dissipation material 131: Heat dissipation tab 132: Heat dissipation fin 210: Upper battery case 220: Lower battery case 300: Electrode lead Ac': (conventional) storage unit Ed': (conventional) edge E1: 1st electrode part E2: 2nd electrode part Ra: Heat dissipation part Ac: Containment unit Jo:Joint

Claims

1. an electrode assembly including a first electrode portion including a unit cell, a second electrode portion including the unit cell, and a heat dissipation portion including a heat dissipation member; a battery case including an upper battery case and a lower battery case, the battery case including a receiving portion that receives the electrode assembly and a joint portion that is extended along an edge of the receiving portion; the heat dissipation portion is interposed between the first electrode portion and the second electrode portion, The unit cell includes a positive electrode plate including a positive electrode current collector, a positive electrode tab drawn from one end of the positive electrode current collector, and a positive electrode mixture coated on the surface of the positive electrode current collector; a negative electrode plate including a negative electrode current collector, a negative electrode tab drawn out from one end of the negative electrode current collector, and a negative electrode mixture coated on a surface of the negative electrode current collector; a separator interposed between the positive electrode plate and the negative electrode plate, the heat dissipation member further includes a heat dissipation tab extending from a position corresponding to one of the positive electrode tab and the negative electrode tab, the positive electrode tab is connected to a heat dissipation tab at a position corresponding to the positive electrode tab, the negative electrode tab is connected to a heat radiation tab at a position corresponding to the negative electrode tab, A lithium secondary battery with an ignition suppression structure, wherein the total thickness of the heat dissipation member included in the heat dissipation part is 8 times or less the thickness of the positive electrode current collector.

2. The lithium secondary battery with an ignition suppression structure according to claim 1 , wherein each of the first electrode unit and the second electrode unit includes at least one unit cell.

3. The lithium secondary battery with an ignition suppression structure according to claim 2 , wherein the number of unit cells included in the first electrode part is the same as the number of unit cells included in the second electrode part.

4. Between the heat dissipation portion and the first electrode portion, and The lithium secondary battery with an ignition suppression structure according to claim 1 , wherein a separator is interposed between the heat dissipation portion and the second electrode portion.

5. the heat dissipation unit includes a plurality of heat dissipation members, 2. The lithium secondary battery with an ignition suppression structure according to claim 1, wherein a separator is interposed between each of the heat dissipation members.

6. 2. The lithium secondary battery with an ignition suppression structure according to claim 1, wherein the heat dissipation member includes at least one of copper, aluminum, nickel, a copper alloy, a nickel alloy, titanium, stainless steel, and carbon.

7. The heat dissipation member has a plate-like shape, 7. The lithium secondary battery with an ignition suppression structure according to claim 1, wherein the length and width of the heat dissipation member do not exceed the length and width of the positive electrode current collector or the negative electrode current collector.

8. The lithium secondary battery with an ignition suppression structure according to claim 1 , wherein the total thickness of the heat dissipation member included in the heat dissipation part is greater than the thickness of the positive electrode current collector or the negative electrode current collector.

9. The lithium secondary battery with an ignition suppression structure according to claim 1 , wherein the heat dissipation member further comprises a heat dissipation fin extending from one end portion where the positive electrode tab and the negative electrode tab are not located.

10. The heat dissipation fin does not extend beyond the joint of the battery case, The lithium secondary battery with an ignition suppression structure according to claim 9 , wherein the ignition suppression structure is interposed between the joint portion of the upper battery case and the joint portion of the lower battery case.

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