Cylindrical batteries and battery packs

Abstract

The present invention provides a cylindrical battery and a battery pack, wherein the cylindrical battery comprises a shell and a battery cell arranged in the shell, the battery cell comprises a first pole ear and a second pole ear, the first pole ear and the second pole ear are both located on the same side of the battery cell, and the polarities of the first pole ear and the second pole ear are opposite; the shell comprises a circumferential side wall and a first end wall and a second end wall located at both ends of the circumferential side wall, a pole assembly is arranged on the first end wall, a first output pole is arranged on the shell of the cylindrical battery, a second output pole is arranged on the first end wall, and a first insulating layer and a second insulating layer are arranged on the outer circumferential surface of the battery cell. During the use of the cylindrical battery, the connection position of the first pole ear and the second pole ear with the pole assembly has a large heat generation, and the first insulating layer has a high thermal deformation temperature, so it can withstand the high temperature of the connection position, and prevent the first insulating layer from melting due to high temperature and falling off from the battery cell.

Description

Technical Field

[0001] The present invention relates to the technical field of new energy batteries, and in particular to a cylindrical battery and a battery pack. Background Art

[0002] The battery pack is a key component of new energy vehicles, and the battery pack includes multiple batteries. The battery includes a cell, and the cell includes a tab. The tab is welded to the pole on the end cover, so that the cell is connected to the external electrical equipment. In order to ensure the insulation performance of the cell, the cell is covered with an insulating film.

[0003] When the battery is in use, the current will pass through the pole and the lug. Since both are made of metal, a lot of heat will be generated in the area where the lug and the pole are connected. The insulating film near this area may be affected by the high temperature and melt, causing the insulating film to fall off the battery cell, affecting the normal use of the battery. Summary of the invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the defect in the prior art that the insulating film located near the connection area between the lug and the pole is easily affected by high temperature during use of the battery, thereby providing a cylindrical battery and a battery pack.

[0005] In order to solve the above problems, the present invention provides a cylindrical battery, comprising a shell and a battery cell arranged in the shell, the battery cell comprising a first pole ear and a second pole ear, the first pole ear and the second pole ear are both located on the same side of the battery cell, and the polarities of the first pole ear and the second pole ear are opposite; the shell comprises a circumferential side wall and a first end wall and a second end wall located at both ends of the circumferential side wall, a pole assembly is arranged on the first end wall, a first output pole is arranged on the shell of the cylindrical battery, a second output pole is arranged on the first end wall, a first insulating layer and a second insulating layer are arranged on the outer peripheral surface of the battery cell, the first insulating layer is arranged close to the first end wall, the second insulating layer is located on the side of the first insulating layer away from the first end wall, and the thermal deformation temperature of the first insulating layer is greater than the thermal deformation temperature of the second insulating layer.

[0006] Optionally, the heat deformation temperature of the first insulating layer is in the range of 220-280°C; and / or the heat deformation temperature of the second insulating layer is in the range of 100-150°C.

[0007] Optionally, the shell serves as the first output pole, the pole assembly serves as the second output pole, and the first pole lug and the second pole lug are electrically connected to the shell and the pole assembly respectively.

[0008] Optionally, in the axial direction of the battery core, a distance between an edge of the first insulating layer facing the first end wall and the first end wall is in a range of 0 to 4 mm.

[0009] Optionally, along the axial direction of the battery core, the size of the first insulating layer is smaller than the size of the second insulating layer.

[0010] Optionally, in the axial direction of the battery core, a ratio of a size of the first insulating layer to a size of the second insulating layer is in a range of 0.04 to 0.21.

[0011] Optionally, when the radius of the cylindrical battery is greater than or equal to 40 mm, the ratio of the size of the first insulating layer to the size of the second insulating layer is in the range of 0.06 to 0.18.

[0012] Optionally, along the axial direction of the battery core, a size of the first insulating layer is in a range of 8 mm to 18 mm.

[0013] Optionally, there is an overlapping portion between the first insulating layer and the second insulating layer, and a size of the overlapping portion is in a range of 0 to 4 mm along the axial direction of the battery core.

[0014] Optionally, when the ratio of the area of ​​the first tab end face to the area of ​​the second tab end face is in the range of 0.5 to 1, the distance from the edge of the overlapping portion close to the first end wall to the first end wall is in the range of 10 mm to 18 mm.

[0015] Optionally, a ratio of the thickness of the first insulating layer to the thickness of the second insulating layer is in a range of 0.6 to 1.2.

[0016] The present invention also provides a battery pack, comprising the above cylindrical battery.

[0017] The present invention has the following advantages:

[0018] Utilizing the technical solution of the present invention, a first insulating layer and a second insulating layer are provided on the outer peripheral surface of the battery cell, and the first insulating layer is provided close to the pole assembly. During the use of the cylindrical battery, the position of the pole assembly has a large heat generation, and the first insulating layer has a high heat deformation temperature, so it can withstand the high temperature at the connection position and prevent the first insulating layer from melting due to high temperature and falling off the battery cell. The second insulating layer is relatively less affected by high temperature, so the heat deformation temperature of the second insulating layer is relatively low, ensuring that the second insulating layer has good heat dissipation capabilities and preventing high heat accumulation on the surface of the battery cell. Therefore, the technical solution of the present invention solves the defect in the prior art that the insulating film located near the connection area between the pole ear and the pole is easily affected by high temperature during the use of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 A schematic diagram showing the structure of a cylindrical battery of the present invention is shown;

[0021] Figure 2 Shows Figure 1 A schematic diagram of the structure of the first end wall and the battery cell of a medium cylindrical battery;

[0022] Figure 3 Shows Figure 2 A schematic front view of the first end wall and the battery cell;

[0023] Figure 4 Shows Figure 2 Schematic diagram of the first insulating layer and the second insulating layer of the battery cell having overlapping parts.

[0024] Description of reference numerals:

[0025] 10. Shell; 20. Battery cell; 11. Circumferential side wall; 12. First end wall; 13. Second end wall; 14. Pole assembly; 30. First insulating layer; 40. Second insulating layer; 50. Overlapping portion. DETAILED DESCRIPTION

[0026] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0028] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0029] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0030] like Figures 1 to 3 As shown, an embodiment of a cylindrical battery according to the present application includes a housing 10 and a battery cell 20 disposed in the housing 10. The battery cell 20 includes a first pole ear and a second pole ear, the first pole ear and the second pole ear are both located on the same side of the battery cell 20, and the polarities of the first pole ear and the second pole ear are opposite. The housing 10 includes a circumferential side wall 11 and a first end wall 12 and a second end wall 13 located at both ends of the circumferential side wall 11, and a pole assembly 14 is disposed on the first end wall 12. A first output stage is disposed on the housing 10 of the cylindrical battery, and a second output stage is disposed on the first end wall 12.

[0031] Furthermore, a first insulating layer 30 and a second insulating layer 40 are provided on the outer peripheral surface of the battery cell 20, the first insulating layer 30 is arranged close to the first end wall 12, the second insulating layer 40 is located on the side of the first insulating layer 30 away from the first end wall 12, and the thermal deformation temperature of the first insulating layer 30 is greater than the thermal deformation temperature of the second insulating layer 40.

[0032] Utilizing the technical solution of this embodiment, a first insulating layer 30 and a second insulating layer 40 are provided on the outer peripheral surface of the battery cell 20, and the first insulating layer 30 is provided close to the pole assembly 14. During the use of the cylindrical battery, the position of the pole assembly 14 has a large heat generation, and the first insulating layer 30 has a high heat deformation temperature, so it can withstand the high temperature at the connection position, and prevent the first insulating layer 30 from melting due to high temperature and falling off the battery cell 20. The second insulating layer 40 is relatively less affected by high temperature, so the heat deformation temperature of the second insulating layer 40 is relatively low, ensuring that the second insulating layer 40 has good heat dissipation ability, and preventing high heat from accumulating on the surface of the battery cell 20. Therefore, the technical solution of this embodiment solves the defect in the prior art that the insulating film located near the connection area between the pole ear and the pole is easily affected by high temperature during the use of the battery.

[0033] It should be noted that, among the first electrode tab and the second electrode tab, one is a positive electrode tab and the other is a negative electrode tab.

[0034] Furthermore, the test method for the high temperature resistance of the first insulating layer 30 and the second insulating layer 40 in this embodiment refers to the national standard GB / T1634-2004 plastic thermal deformation temperature and heat resistance test method.

[0035] like Figure 1 As shown, the cylindrical battery is a cylindrical structure as a whole, and the shell 10 of the cylindrical battery includes a circumferential side wall 11, a first end wall 12 and a second end wall 13. Among them, the circumferential side wall 11 is a cylindrical structure, and the second end wall 13 is connected to the end of the circumferential side wall 11. The two can be integrally formed, or can be connected by welding, bonding or fasteners. The circumferential side wall 11 and the second end wall 13 form a structure with one end open.

[0036] from Figure 1 and Figure 2 It can be seen that the first end wall 12 is provided with a pole assembly 14. During assembly, the first pole lug and / or the second pole lug on the battery cell 20 is first connected to the pole assembly 14, that is, the first end wall 12 is connected to the battery cell 20. Then the battery cell 20 is placed in the space enclosed by the circumferential side wall 11 and the second end wall 13. At this time, the first end wall 12 is covered at the opening of the circumferential side wall 11, and finally the first end wall 12 is welded to the circumferential side wall 11.

[0037] Furthermore, in order to isolate the battery core 20 from other structures, an insulating layer is coated on the battery core 20. The insulating layer may be an insulating film, which is attached to the outer peripheral surface of the battery core 20 along the circumferential direction.

[0038] Furthermore, in order to reduce the influence of heat generation at the pole assembly 14 on the insulating layer, in this embodiment, the insulating layer is divided into a first insulating layer 30 and a second insulating layer 40 .

[0039] Specifically, from Figure 2 and Figure 3 It can be seen that the first insulating layer 30 and the second insulating layer 40 are both wrapped around the battery core 20 along the circumferential direction. The first insulating layer 30 and the second insulating layer 40 are distributed along the axial direction of the battery core 20, and the first insulating layer 30 is arranged close to the first end wall 12, that is, the first insulating layer 30 is arranged close to the connection position. The thermal deformation temperature of the first insulating layer 30 is greater than the thermal deformation temperature of the second insulating layer 40, and the height of the first insulating layer 30 is less than the height of the second insulating layer 40 along the axial direction of the battery core 20.

[0040] In this embodiment, the first insulating layer 30 is close to the pole assembly 14 and has a high thermal deformation temperature. Therefore, when the cylindrical battery is working, the heat generated by the pole assembly 14 has little effect on the first insulating layer 30. The first insulating layer 30 can withstand high temperatures to prevent the first insulating layer 30 from melting at high temperatures and falling off the battery cell 20.

[0041] Furthermore, since the first insulating layer 30 has a relatively high thermal deformation temperature, the heat dissipation capacity of the first insulating layer 30 is correspondingly reduced. In order to ensure the overall heat dissipation capacity of the battery cell 20, the thermal deformation temperature of the second insulating layer 40 is set to be slightly lower than that of the first insulating layer 30. Since the second insulating layer 40 is far away from the pole assembly 14, the heat generated by the pole assembly 14 has little effect on the second insulating layer 40 and will not cause it to melt. In addition, the second insulating layer 40 has a relatively low thermal deformation temperature and has good heat dissipation performance, thereby ensuring the overall heat dissipation capacity of the battery cell 20.

[0042] Optionally, the thermal deformation temperature of the first insulating layer 30 is in the range of 220°C to 280°C.

[0043] Specifically, the thermal deformation temperature of the first insulating layer 30 should not be too small or too large. If the thermal deformation temperature of the first insulating layer 30 is too large, it is not conducive to the heat dissipation of the cylindrical battery. If the thermal deformation temperature of the first insulating layer 30 is too small, it cannot resist the high temperature generated at the pole assembly 14.

[0044] For example, the thermal deformation temperature of the first insulating layer 30 may be selected as 220° C., 240° C., 260° C., 280° C., or any value between two values.

[0045] Optionally, the thermal deformation temperature of the second insulating layer 40 is in the range of 100°C to 150°C.

[0046] Specifically, the thermal deformation temperature of the second insulating layer 40 should not be too small or too large. If the thermal deformation temperature of the second insulating layer 40 is too large, it is not conducive to the heat dissipation of the cylindrical battery. If the thermal deformation temperature of the second insulating layer 40 is too small, the second insulating layer 40 will be thermally deformed quickly when heated, and insulation failure is very likely to occur. Even in the working environment of the cylindrical battery at normal temperature, the second insulating layer 40 may be deformed or even melted.

[0047] For example, the thermal deformation temperature of the second insulating layer 40 may be selected as 100° C., 110° C., 120° C., 130° C., 140° C., or 150° C., or a value between any two values.

[0048] Furthermore, it is necessary to ensure that the thermal deformation temperature of the first insulating layer 30 is greater than the thermal deformation high temperature of the second insulating layer 40 .

[0049] Furthermore, in the above-mentioned configuration of the first output stage and the second output stage, the housing 10 is used as the first output stage, and the pole assembly 14 is used as the second output stage. At this time, the first pole tab is electrically connected to the housing 10 , and the second pole tab is electrically connected to the pole assembly 14 .

[0050] like Figure 3 As shown, in the technical solution of this embodiment, in the axial direction of the battery core 20 , a distance d1 between the edge of the first insulating layer 30 facing the first end wall 12 and the first end wall 12 is in the range of 0 to 4 mm.

[0051] It should be noted that the above range of d1 does not include 0.

[0052] Specifically, during the use of the cylindrical battery, the first end wall 12 plays a role in carrying the overcurrent, so the first end wall 12 has a large heat generation and a high temperature. Therefore, the above distance d1 should take an appropriate value.

[0053] First, the distance d1 cannot be too small. If the distance d1 is too small, it means that the first insulating layer 30 is closer to the first end wall 12. Therefore, when the cylindrical battery is working, the heat of the first end wall 12 is more easily transferred to the first insulating layer 30, which is more likely to cause the first insulating layer 30 to melt.

[0054] Secondly, the distance d1 cannot be too large. If the distance d1 is too small, it means that the first insulating layer 30 is far away from the first end wall 12, so the exposed area of ​​the outer surface of the battery cell 20 is large, which weakens the insulation performance and heat dissipation performance of the first insulating layer 30 on the battery cell 20. Optionally, the distance d1 can be selected as 0.5 mm, 1 mm, 2 mm, 3 mm or 4 mm, etc., and a value between any two values.

[0055] Furthermore, in the technical solution of this embodiment, along the axial direction of the battery core 20 , a size d2 of the first insulating layer 30 is smaller than a size d3 of the second insulating layer 40 .

[0056] Specifically, for the insulating layer, good high temperature resistance will lead to poor heat dissipation. Therefore, if the size d2 of the first insulating layer 30 is too large, it will affect the heat dissipation of the cylindrical battery, especially when it is wrapped in the area with high heat near the top of the cylindrical battery. The heat cannot be dissipated outward, which can easily cause thermal runaway of the cylindrical battery. Therefore, the size d2 of the first insulating layer 30 needs to be set relatively small.

[0057] Furthermore, the second insulating layer 40 has poor high temperature resistance, so its heat dissipation capability is relatively strong. Therefore, the size d2 of the second insulating layer 40 needs to be set relatively large to ensure the overall heat dissipation performance of the cylindrical battery.

[0058] Therefore, based on comprehensive considerations, in this embodiment, the size d2 of the first insulating layer 30 is smaller than the size d3 of the second insulating layer 40 .

[0059] like Figure 3As shown, in the technical solution of this embodiment, along the axial direction of the battery core 20, the ratio of the size d2 of the first insulating layer 30 to the size d3 of the second insulating layer 40 is in the range of 0.04 to 0.21.

[0060] from Figure 3 It can be seen that Figure 3 The dimension d2 of the first insulating layer 30 is the height of the first insulating layer 30 in the vertical direction, and the dimension d3 of the second insulating layer 40 is the height of the second insulating layer 40 in the vertical direction.

[0061] First, the ratio of the size d2 of the first insulating layer 30 to the size d3 of the second insulating layer 40 cannot be too large. If the ratio is too large, it means that the height of the first insulating layer 30 is larger than the height of the second insulating layer 40. As mentioned above, although the first insulating layer 30 has strong high temperature resistance, its heat dissipation capacity is relatively low. Therefore, if the ratio of d2 to d3 is large, the overall heat dissipation performance of the battery cell 20 will be reduced. And because the height of the second insulating layer 40 is greater than the height of the first insulating layer 30, the second insulating layer 40 also plays the role of tightening the wound battery cell 20. If the size d3 of the second insulating layer 40 is relatively small, it will cause the second insulating layer 40 to reduce its ability to wrap and tighten the battery cell 20, making the inside of the battery cell 20 loose, affecting the performance of the cylindrical battery.

[0062] Secondly, the ratio of the size d2 of the first insulating layer 30 to the size d3 of the second insulating layer 40 cannot be too small. If the ratio is too small, it means that the height of the first insulating layer 30 is smaller than the height of the second insulating layer 40. This will reduce the overall area of ​​the first insulating layer 30, reduce its tolerance to high temperatures, and more easily cause the heat on the first end wall 12 to continue to transfer downward from the first insulating layer 30 to the second insulating layer 40, which is likely to cause the second insulating layer 40 to melt.

[0063] Optionally, the ratio of the size d2 of the first insulating layer 30 to the size d3 of the second insulating layer 40 can be selected as 0.04, 0.08, 0.1, 0.15, 0.2 or 0.21, etc., and a value between any two values.

[0064] Further, in the technical solution of this embodiment, along the axial direction of the battery core 20 , a dimension d2 of the first insulating layer 30 is in the range of 8 mm to 18 mm.

[0065] Specifically, the height d2 of the first insulating layer 30 should be within a suitable range. If the size of d2 is too large, the first insulating layer 30 with poor heat dissipation capacity will be larger, affecting the overall heat dissipation capacity of the cylindrical battery. If the size of d2 is too small, the second insulating layer 40 will still be attached to the high temperature area close to the first end wall 12, which may easily cause the second insulating layer 40 to melt and insulation failure.

[0066] For example, the size d2 of the first insulating layer 30 can be 8 mm, 9 mm, 10 mm, 12 mm, 15 mm, 18 mm, or any value between any two values.

[0067] In the technical solution of this embodiment, when the radius of the cylindrical battery is greater than or equal to 40 mm, the ratio of the size d2 of the first insulating layer 30 to the size d3 of the second insulating layer 40 is in the range of 0.06 to 0.18.

[0068] Specifically, for cylindrical batteries, the larger the radius, the larger the radius of the battery cell, so the higher the energy density, and the greater the heat generated by the cylindrical battery during operation. In particular, the temperature is high at the top (the location of the first end wall 12) where the heat is more concentrated. At this time, the size d2 of the first insulating layer 30 should be appropriately increased to cope with the high temperature. That is, the larger the radius of the cylindrical battery, the ratio of the size d2 of the first insulating layer 30 to the size d3 of the second insulating layer 40 should be appropriately increased.

[0069] like Figure 4 As shown, in the technical solution of this embodiment, there is an overlapping portion 50 between the first insulating layer 30 and the second insulating layer 40 , and along the axial direction of the battery core 20 , a size d4 of the overlapping portion 50 is in the range of 0 to 4 mm.

[0070] It should be noted that the value range of d4 mentioned above does not include 0.

[0071] Specifically, the overlapping portion 50 may be formed by the first insulating layer 30 covering a portion of the second insulating layer 40 on the outside and downward (toward the second end wall 13 ), or the second insulating layer 40 covering a portion of the first insulating layer 30 on the outside and upward (toward the first end wall 12 ).

[0072] The reason for setting the overlapping portion 50 in this embodiment is to ensure that the outer peripheral surface of the battery cell 20 is completely wrapped by the first insulating layer 30 and the second insulating layer 40, thereby ensuring the insulation performance of the first insulating layer 30 and the second insulating layer 40 to the battery cell 20 and improving the heat dissipation effect.

[0073] In some embodiments not shown, Figure 3The direction shown is used for explanation. The lower edge of the first insulating layer 30 and the upper edge of the second insulating layer 40 may be arranged in close contact or with a certain distance therebetween.

[0074] like Figure 4 As shown, and Figure 4 The dimension d4 of the overlapping portion 50 , that is, the height value of the overlapping portion 50 , is described in the direction shown.

[0075] First, the size d4 of the overlapping portion 50 cannot be too large. If the value of d4 is too large, it means that the overlapping portion 50 of the first insulating layer 30 and the second insulating layer 40 is large. On the one hand, the thicker overlapping portion 50 will occupy the space of the cylindrical battery, making the capacity of the cylindrical battery smaller. On the other hand, it means that the overlapping portion 50 of the first insulating layer 30 and the second insulating layer 40 is large, making it easier for the heat of the first insulating layer 30 to transfer downward to the second insulating layer 40, and it is easy for the second insulating layer 40 to be melted.

[0076] Secondly, the size d4 of the overlapping part 50 cannot be too small. If the value of d4 is too small, it means that the overlapping part 50 of the first insulating layer 30 and the second insulating layer 40 is small, and the heat of the first insulating layer cannot be quickly conducted through the second insulating layer, resulting in excessive heat in the first insulating layer.

[0077] For example, the dimension d4 of the overlapping portion 50 may be selected to be 0.05 mm, 1 mm, 1.5 mm, 2 mm, 3 mm, or 4 mm, etc., and a value between any two values.

[0078] Furthermore, in the technical solution of this embodiment, when the ratio of the area of ​​the first pole ear end face to the area of ​​the second pole ear end face is in the range of 0.5 to 1, the edge of the overlapping portion 50 close to the first end wall 12 is at a distance from the first end wall 12 of 10 mm to 18 mm.

[0079] Specifically, since the overlapping portion 50 is formed by stacking the first insulating layer 30 and the second insulating layer 40, the thickness of the overlapping portion 50 is relatively thick, which will hinder heat dissipation. Therefore, in this embodiment, it is necessary to make the overlapping portion 50 have a certain distance from the top area (first end wall 12) where heat is concentrated. That is, Figure 4 In the illustrated embodiment, the distance between the upper edge of the overlapped portion 50 and the first end wall 12 is in the range of 10 mm to 18 mm.

[0080] For example, the distance between the edge of the overlapping portion 50 on the side close to the first end wall 12 and the first end wall 12 can be selected as 10 mm, 12 mm, 14 mm, 15 mm, 16 mm or 18 mm, etc., and a value between any two values.

[0081] Further, in the technical solution of this embodiment, the ratio of the thickness of the first insulating layer 30 to the thickness of the second insulating layer 40 is in the range of 0.6 to 1.2.

[0082] Specifically, in this embodiment, the thickness of the first insulating layer 30 is preferably set to be greater than the thickness of the second insulating layer 40, thereby enhancing the high temperature resistance of the first insulating layer 30 and preventing the heat of the first insulating layer 30 from being easily transferred downward to the second insulating layer 40.

[0083] First, the ratio of the thickness of the first insulating layer 30 to the thickness of the second insulating layer 40 cannot be too large. If the ratio is too large, it means that the thickness of the first insulating layer 30 is thicker than the thickness of the second insulating layer 40. The thicker first insulating layer 30 will occupy the space of the cylindrical battery, making the capacity of the cylindrical battery smaller.

[0084] Secondly, the ratio of the thickness of the first insulating layer 30 to the thickness of the second insulating layer 40 cannot be too small. If the ratio is too small, it means that the thickness of the first insulating layer 30 is similar to the thickness of the second insulating layer 40. A relatively thin first insulating layer 30 will reduce its high temperature resistance, making it easier for the heat of the first insulating layer 30 to transfer downward to the second insulating layer 40, which may cause the second insulating layer 40 to melt.

[0085] For example, the ratio of the thickness of the first insulating layer 30 to the thickness of the second insulating layer 40 can be selected as 0.6, 0.8, 1 or 1.2, etc., and a value between any two values.

[0086] The present application also provides a battery pack. According to an embodiment of the battery pack of the present application, the battery pack includes the above-mentioned cylindrical battery.

[0087] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. A cylindrical battery, characterized in that: The battery cell (20) comprises a shell (10) and a battery cell (20) arranged in the shell (10), wherein the battery cell (20) comprises a first pole ear and a second pole ear, wherein the first pole ear and the second pole ear are both located on the same side of the battery cell (20), and the polarities of the first pole ear and the second pole ear are opposite; the shell (10) comprises a circumferential side wall (11) and a first end wall (12) and a second end wall (13) located at both ends of the circumferential side wall (11), wherein a pole column assembly (14) is arranged on the first end wall (12), and a first output pole is arranged on the shell (10) of the cylindrical battery, and a second output pole is arranged on the first end wall (12). The outer peripheral surface of the battery core (20) is provided with a first insulating layer (30) and a second insulating layer (40), the first insulating layer (30) is provided close to the first end wall (12), the second insulating layer (40) is located on a side of the first insulating layer (30) away from the first end wall (12), and the thermal deformation temperature of the first insulating layer (30) is greater than the thermal deformation temperature of the second insulating layer (40). The thermal deformation temperature of the first insulating layer (30) is in the range of 220-280°C; and / or the thermal deformation temperature of the second insulating layer (40) is in the range of 100-150°C, The thickness of the first insulating layer (30) is set to be greater than the thickness of the second insulating layer (40), thereby enhancing the high temperature resistance of the first insulating layer (30).

2. The cylindrical battery according to claim 1, characterized in that: The housing (10) serves as the first output pole, the pole assembly (14) serves as the second output pole, and the first pole lug and the second pole lug are electrically connected to the housing (10) and the pole assembly (14), respectively.

3. The cylindrical battery according to claim 1, characterized in that: In the axial direction of the battery core (20), a distance (d1) between an edge of the first insulating layer (30) facing the first end wall (12) and the first end wall (12) is in the range of 0 to 4 mm.

4. The cylindrical battery according to claim 1, characterized in that: In the axial direction of the battery core (20), the size (d2) of the first insulating layer (30) is smaller than the size (d3) of the second insulating layer (40).

5. The cylindrical battery according to any one of claims 1 to 4, characterized in that: In the axial direction of the battery core (20), the ratio of the size (d2) of the first insulating layer (30) to the size (d3) of the second insulating layer (40) is in the range of 0.04 to 0.

21.

6. The cylindrical battery according to claim 5, characterized in that: When the radius of the cylindrical battery is greater than or equal to 40 mm, the ratio of the size (d2) of the first insulating layer (30) to the size (d3) of the second insulating layer (40) is in the range of 0.06 to 0.

18.

7. The cylindrical battery according to any one of claims 1 to 4, characterized in that: In the axial direction of the battery core (20), a dimension (d2) of the first insulating layer (30) is in the range of 8 mm to 18 mm.

8. The cylindrical battery according to claim 1, characterized in that: An overlapping portion (50) is provided between the first insulating layer (30) and the second insulating layer (40), and a size (d4) of the overlapping portion (50) is in the range of 0 to 4 mm in the axial direction of the battery core (20).

9. The cylindrical battery according to claim 8, characterized in that: When the ratio of the area of ​​the first pole lug end face to the area of ​​the second pole lug end face is in the range of 0.5 to 1, the distance between the edge of the overlapping portion (50) on the side close to the first end wall (12) and the first end wall (12) is in the range of 10 mm to 18 mm.

10. The cylindrical battery according to any one of claims 1 to 4, characterized in that: The ratio of the thickness of the first insulating layer (30) to the thickness of the second insulating layer (40) is greater than 1 and less than or equal to 1.

2.

11. A battery pack, characterized in that: Comprising the cylindrical battery as claimed in any one of claims 1 to 10.

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