Cylindrical battery

Abstract

The utility model relates to the technical field of batteries, and provides a cylindrical battery which comprises a battery shell, the battery cell is arranged in the battery shell; the pole assembly is arranged on the first end wall; the anti-explosion valve is arranged on the first end wall; at least part of the insulating part is positioned in the battery shell; wherein the insulating part is provided with a weak area, orthographic projections of the weak area and the explosion-proof valve towards the plane where the first end wall is located are a first orthographic projection and a second orthographic projection respectively, at least part of the first orthographic projection and at least part of the second orthographic projection coincide, or the distance between the first orthographic projection and the second orthographic projection in the radial direction of the first end wall is k, k is larger than 0 and smaller than or equal to 5 mm, so that when the cylindrical battery is exploded, the weak area of the insulating part is also disconnected, blocking of separation of the middle anti-explosion valve and the first end wall is reduced, normal pressure relief is guaranteed, and then the safe use performance of the cylindrical battery is guaranteed.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, in particular to a cylindrical battery. Background Art

[0002] In the related art, an explosion-proof valve can be provided on the shell of a cylindrical battery, so that when the pressure inside the shell reaches a certain height, the explosion-proof valve can be opened in time, thereby releasing the pressure inside the shell and avoiding battery safety risks. However, due to the structural limitations of the insulating parts inside the shell, the explosion of the explosion-proof valve may be affected. Utility Model Content

[0003] The utility model provides a cylindrical battery to improve the use performance of the cylindrical battery.

[0004] The utility model provides a cylindrical battery, comprising:

[0005] A battery housing, the battery housing comprising a first end wall, a second end wall and a side wall, wherein the first end wall and the second end wall are connected to opposite ends of the side wall respectively;

[0006] A battery cell, wherein the battery cell is disposed in a battery casing;

[0007] A pole assembly, which is disposed on the first end wall and is electrically connected to the battery cell;

[0008] An explosion-proof valve is arranged on the first end wall and around the pole assembly;

[0009] An insulating member, at least part of which is located in the battery housing and between the first end wall and the battery core, and an area enclosed by an outermost contour of the insulating member is larger than an area enclosed by an outermost contour of the explosion-proof valve;

[0010] Wherein, a weak area is provided on the insulating part, and the weak area and the orthographic projection of the explosion-proof valve on the plane where the first end wall is located are respectively the first orthographic projection and the second orthographic projection, and at least part of the first orthographic projection and the second orthographic projection overlap, or, along the radial direction of the first end wall, the distance between the first orthographic projection and the second orthographic projection is k, 0<k≤5mm.

[0011] The cylindrical battery of the utility model embodiment includes a battery housing, a battery cell, a pole assembly, an explosion-proof valve and an insulating member. The battery cell is arranged in the battery housing, the pole assembly is arranged on the first end wall of the battery housing, the pole assembly is electrically connected to the battery cell, and the explosion-proof valve is arranged on the first end wall around the pole assembly, so that when the internal pressure of the battery housing reaches a certain height, the explosion-proof valve can explode, thereby releasing the internal pressure. At least part of the insulating member is located between the first end wall and the battery cell, thereby ensuring the insulation capacity between the first end wall and the battery cell and avoiding the risk of short circuit. By providing a weak area on the insulating member, the weak area and the orthographic projection of the explosion-proof valve on the plane where the first end wall is located are respectively the first orthographic projection and the second orthographic projection, and at least part of the first orthographic projection and the second orthographic projection overlap, or, along the radial direction of the first end wall, the distance between the first orthographic projection and the second orthographic projection is k, 0<k≤5mm, thereby avoiding obstruction by the insulating member, causing the gas to be unable to quickly reach the explosion-proof valve area, affecting the separation of the explosion-proof valve and the first end wall. Therefore, when the cylindrical battery explodes, the insulating member can also be disconnected near the weak area, reducing the obstruction to the separation of the middle explosion-proof valve and the first end wall, ensuring normal pressure relief, and further ensuring the safe use performance of the cylindrical battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to better understand the present disclosure, reference may be made to the embodiments shown in the following drawings. The components in the drawings are not necessarily to scale, and related elements may be omitted in order to emphasize and clearly illustrate the technical features of the present disclosure. In addition, related elements or components may have different arrangements as known in the art. In addition, in the drawings, the same reference numerals represent the same or similar components in each drawing. Among them:

[0013] Figure 1 is a schematic structural diagram of a cylindrical battery according to an exemplary embodiment;

[0014] Figure 2 is a schematic diagram of a partial cross-sectional structure of a cylindrical battery according to an exemplary embodiment;

[0015] Figure 3A is a partial structural schematic diagram of a cylindrical battery according to an exemplary embodiment;

[0016] Figure 3B is a partial structural schematic diagram of a cylindrical battery according to another exemplary embodiment;

[0017] Figure 4 is a schematic diagram of a partial cross-sectional structure of a cylindrical battery according to an exemplary embodiment;

[0018] Figure 5is a schematic diagram of a partial cross-sectional structure of a cylindrical battery according to another exemplary embodiment.

[0019] The following are the descriptions of the reference numerals:

[0020] 10. Battery casing; 11. First end wall; 12. Second end wall; 13. Side wall; 20. Battery cell; 30. Pole assembly; 40. Explosion-proof valve; 50. Insulator; 51. Weak area; 52. Connection area; 53. Middle part; 54. Edge part. DETAILED DESCRIPTION

[0021] The following will be combined with the accompanying drawings in the exemplary embodiments of the present disclosure to clearly and completely describe the technical solutions in the exemplary embodiments of the present disclosure. The exemplary embodiments described herein are only for illustrative purposes and are not intended to limit the scope of protection of the present disclosure. Therefore, it should be understood that various modifications and changes can be made to the exemplary embodiments without departing from the scope of protection of the present disclosure.

[0022] In the description of the present disclosure, unless otherwise clearly specified and limited, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance; the term "plurality" refers to two or more; the term "and / or" includes any and all combinations of one or more associated listed items. In particular, reference to "the / the" object or "an" object is also intended to indicate one of a possible plurality of such objects.

[0023] Unless otherwise specified or explained, the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, an integral connection, an electrical connection, or a signal connection; "connection" can be a direct connection or an indirect connection through an intermediate medium. For those skilled in the art, the specific meanings of the above terms in this disclosure can be understood according to specific circumstances.

[0024] Further, in the description of the present disclosure, it should be understood that the directional words such as "upper", "lower", "inner", "outer" and the like described in the exemplary embodiments of the present disclosure are described at the angles shown in the accompanying drawings and should not be understood as limitations on the exemplary embodiments of the present disclosure. It should also be understood that, in the context, when it is mentioned that an element or feature is connected to another element (one or more) "upper", "lower", or "inner", "outer", it can not only be directly connected to the other (one or more) elements "upper", "lower", "inner", "outer", but also can be indirectly connected to the other (one or more) elements "upper", "lower", "inner", "outer" through an intermediate element.

[0025] An embodiment of the utility model provides a cylindrical battery, please refer to Figures 1 to 5 The cylindrical battery comprises: a battery housing 10, the battery housing 10 comprises a first end wall 11, a second end wall 12 and a side wall 13, the first end wall 11 and the second end wall 12 being connected to the opposite ends of the side wall 13 respectively; a battery cell 20, the battery cell 20 being arranged in the battery housing 10; a pole assembly 30, the pole assembly 30 being arranged on the first end wall 11 and being electrically connected to the battery cell 20; an explosion-proof valve 40, the explosion-proof valve 40 being arranged on the first end wall 11 and being arranged around the pole assembly 30; an insulating member 50, at least a portion of the insulating member 50 being located at the battery The outermost contour of the insulating member 50 is located inside the housing 10 and between the first end wall 11 and the battery cell 20, and the area enclosed by the outermost contour of the insulating member 50 is larger than the area enclosed by the outermost contour of the explosion-proof valve 40; wherein a weak area 51 is provided on the insulating member 50, and the orthographic projections of the weak area 51 and the explosion-proof valve 40 on the plane where the first end wall 11 is located are respectively the first orthographic projection and the second orthographic projection, and at least part of the first orthographic projection overlaps with the second orthographic projection, or, along the radial direction of the first end wall 11, the distance between the first orthographic projection and the second orthographic projection is k, 0<k≤5mm.

[0026] The cylindrical battery of one embodiment of the utility model comprises a battery case 10, a battery cell 20, a pole assembly 30, an explosion-proof valve 40 and an insulating member 50. The battery cell 20 is arranged in the battery case 10, the pole assembly 30 is arranged on the first end wall 11 of the battery case 10, the pole assembly 30 is electrically connected to the battery cell 20, and the explosion-proof valve 40 is arranged on the first end wall 11 around the pole assembly 30, so that after the internal pressure of the battery case 10 reaches a certain height, the explosion-proof valve 40 can explode, thereby forming an internal pressure release. At least part of the insulating member 50 is located between the first end wall 11 and the battery cell 20, thereby ensuring the insulation capacity between the first end wall 11 and the battery cell 20, and avoiding the risk of causing a short circuit. By providing a weak area 51 on the insulating member 50, the weak area 51 and the orthographic projection of the explosion-proof valve 40 on the plane where the first end wall 11 is located are respectively the first orthographic projection and the second orthographic projection, and at least part of the first orthographic projection and the second orthographic projection overlap, or, along the radial direction of the first end wall 11, the distance between the first orthographic projection and the second orthographic projection is k, 0<k≤5mm, so as to avoid obstruction by the insulating member 50, resulting in the inability of the gas to quickly reach the explosion-proof valve 40 area, affecting the separation of the explosion-proof valve 40 and the first end wall 11. Therefore, when the cylindrical battery explodes, the insulating member 50 can also be disconnected near the weak area 51, thereby reducing the obstruction to the separation of the intermediate explosion-proof valve 40 and the first end wall 11, ensuring normal pressure relief, and further ensuring the safe use performance of the cylindrical battery.

[0027] It should be noted that, combined with Figure 1As shown, the battery housing 10 includes a first end wall 11, a second end wall 12 and a side wall 13. The first end wall 11 and the second end wall 12 are respectively connected to the opposite ends of the side wall 13. The side wall 13 is arranged around the circumference of the battery cell 20, and the circumferential outer contours of the first end wall 11 and the second end wall 12 form a circle.

[0028] Combination Figure 2 As shown, the battery cell 20 is arranged in the battery housing 10, and the pole assembly 30 is arranged on the first end wall 11, and the pole lug of the battery cell 20 can be electrically connected to the pole assembly 30. The battery cell 20 may include a first pole lug and a second pole lug, one of the first pole lug and the second pole lug is a positive pole lug, and the other is a negative pole lug. The first pole lug and the second pole lug can be electrically connected to the pole assembly 30 and the battery housing 10 respectively, and the positive pole lug can be electrically connected to the pole assembly 30, and the negative pole lug can be electrically connected to the battery housing 10, or vice versa; or, the battery may further include another pole assembly, and the first pole lug and the second pole lug can be electrically connected to two pole assemblies respectively, and the two pole assemblies can be arranged on the first end wall 11 and the second end wall 12 respectively. The above electrical connection can be a direct connection between the structures, or it can also be connected through a collector plate, which is not limited here.

[0029] like Figure 1 As shown, the explosion-proof valve 40 is arranged on the first end wall 11, and the explosion-proof valve 40 is arranged around the pole assembly 30, so that after the explosion-proof valve 40 explodes, the gas inside the battery housing 10 can be released quickly and evenly, thereby improving the pressure relief efficiency and effectively reducing the safety risks caused.

[0030] The explosion-proof valve 40 is arranged around the pole assembly 30. The explosion-proof valve 40 can be a closed surrounding or a non-closed surrounding. For example, the explosion-proof valve 40 has some discontinuous areas. The discontinuous areas can prevent the explosion-proof valve 40 from flying out directly and overlapping with other structures.

[0031] like Figures 2 to 5 As shown, at least a portion of the insulating member 50 is located within the battery housing 10 and between the first end wall 11 and the battery cell 20, thereby forming insulation protection between the battery cell 20 and the first end wall 11. For example, the insulating member 50 may be a plastic member, or the insulating member 50 may be a rubber member.

[0032] The area enclosed by the outermost contour of the insulating member 50 is larger than the area enclosed by the outermost contour of the explosion-proof valve 40, that is, if the insulating member 50 and the explosion-proof valve 40 are both projected toward the first end wall 11, the orthographic projection formed by the outermost contour of the explosion-proof valve 40 is located within the orthographic projection formed by the outermost contour of the insulating member 50. Therefore, the insulating member 50 will form a barrier to the gas, which is not conducive to the gas reaching the explosion-proof valve 40. Therefore, the weak area 51 can ensure that the gas quickly reaches the explosion-proof valve 40 to form a pressure relief. When the explosion-proof valve 40 is a closed structure, the area enclosed by the outermost contour of the explosion-proof valve 40 can be clearly determined; or, when the explosion-proof valve 40 is a non-closed structure, the area enclosed by the outermost contour of the explosion-proof valve 40 is still calculated according to the circumferential area enclosed by the outer contour.

[0033] Combination Figures 2 to 5 As shown, a weak area 51 is provided on the insulating member 50. The provision of the weak area 51 makes the strength of the insulating member 50 relatively weak. For example, the weak area 51 may be formed by a through hole, or the weak area 51 may be a relatively thin structure, or the weak area 51 may be made of a material different from that of other areas. As an area that is prone to bursting when thermal runaway occurs in the battery, the released gas reaches the explosion-proof valve 40, so that when the battery explodes, the weak area 51 and the vicinity of the weak area 51 are also disconnected, thereby blocking the separation of the explosion-proof valve 40 from the first end wall 11 and ensuring normal pressure relief.

[0034] The orthographic projections of the weak area 51 and the explosion-proof valve 40 on the plane where the first end wall 11 is located are respectively the first orthographic projection and the second orthographic projection, and at least part of the first orthographic projection and the second orthographic projection overlap, or, along the radial direction of the first end wall 11, the distance between the first orthographic projection and the second orthographic projection is k, 0<k≤5mm, that is, the spatial distance between the weak area 51 and the explosion-proof valve 40 is minimized to the greatest extent, so that during the opening process of the explosion-proof valve 40, the insulating member 50 is easily broken, and the resistance to the opening of the explosion-proof valve 40 is reduced, thereby ensuring that the explosion-proof valve 40 is separated from the first end wall 11 in time.

[0035] Combination Figure 3A As shown, the radial direction of the first end wall 11 can be represented as X, the area surrounded by the dotted line in the figure can be represented as the explosion-proof valve 40, and the orthographic projections of the weak area 51 and the explosion-proof valve 40 toward the plane where the first end wall 11 is located are respectively the first orthographic projection and the second orthographic projection, and the first orthographic projection and the second orthographic projection overlap. At this time, along the radial direction of the first end wall 11, the distance between the first orthographic projection and the second orthographic projection can also be considered to be 0.

[0036] The first orthographic projection and the second orthographic projection form an overlapping area, that is, along the axial direction of the cylindrical battery, the weak area 51 is arranged opposite to the explosion-proof valve 40. At this time, when the explosion-proof valve 40 explodes, the stress on the weak area 51 of the insulating member 50 is the greatest, and the battery explosion channel is the smoothest, which can be beneficial to the separation of the explosion-proof valve 40 and the first end wall 11.

[0037] Combination Figure 3B As shown, the radial direction of the first end wall 11 can be represented as X, the area surrounded by the dotted line in the figure can be represented as the explosion-proof valve 40, the orthographic projections of the weak area 51 and the explosion-proof valve 40 toward the plane where the first end wall 11 is located are respectively the first orthographic projection and the second orthographic projection, along the radial direction of the first end wall 11, the distance between the first orthographic projection and the second orthographic projection can be represented as k, and the distance k between the first orthographic projection and the second orthographic projection can be obtained by the minimum distance between the first orthographic projection and the second orthographic projection.

[0038] In the radial direction of the first end wall 11, the distance k between the first orthographic projection and the second orthographic projection can be 0.1mm, 0.2mm, 0.5mm, 0.8mm, 1mm, 1.1mm, 1.2mm, 1.5mm, 1.8mm, 2mm, 2.1mm, 2.2mm, 2.5mm, 2.8mm, 3mm, 3.1mm, 3.2mm, 3.5mm, 3.8mm, 4mm, 4.1mm, 4.2mm, 4.5mm, 4.8mm or 5mm, etc.

[0039] A cylindrical battery includes a battery cell and an electrolyte, which is the smallest unit capable of performing electrochemical reactions such as charge / discharge. A battery cell refers to a unit formed by winding or laminating a stacked portion, which includes a first pole piece, a separator, and a second pole piece. When the first pole piece is a positive pole piece, the second pole piece is a negative pole piece. The polarities of the first pole piece and the second pole piece can be interchanged. The first pole piece and the second pole piece are coated with an active material. The first pole piece, the second pole piece with opposite electrical properties to the first pole piece, and the diaphragm sheet disposed between the first pole piece and the second pole piece are wound to obtain a wound battery cell.

[0040] One of the first and second pole pieces is a negative pole piece, and the other is a positive pole piece. The pole piece may include a current collector and an active material layer, the current collector may be a metal foil, the active material layer is coated on the current collector, and then a wound battery cell is formed by a winding process.

[0041] The current collector may be copper, aluminum or a composite material. For example, the current collector includes a polymer base film layer and a metal layer disposed on the polymer base film layer. The metal layer may be copper or aluminum, and the polymer base film layer may be made of polypropylene (OPP) or polyethylene terephthalate (PET). The active material layer may be a positive electrode material, such as lithium cobalt oxide, lithium manganese oxide, lithium iron phosphate, lithium titanate, etc. Alternatively, the active material layer may be a negative electrode material, such as graphite, hard carbon, soft carbon, mesophase carbon microspheres, silicon carbon, and lithium titanate, etc.

[0042] The electrode sheet can be a positive electrode sheet, that is, the current collector is a positive electrode current collector, and the active material layer is a positive electrode active material. The positive electrode current collector can be an aluminum foil.

[0043] The electrode sheet may be a negative electrode sheet, that is, the current collector is a negative electrode current collector, and the active material layer is a negative electrode active material. The negative electrode current collector may be a copper foil.

[0044] In one embodiment, at least part of the first orthographic projection is located on the inner side of the area enclosed by the second orthographic projection, so that when the cylindrical battery explodes, the insulating member 50 is disconnected from the vicinity of the weak area 51, and the weak area 51 is set in the inner circle of the explosion-proof valve 40 corresponding to the position of the insulating member 50. The disconnection position of the insulating member 50 is in the inner circle, and the obstruction to the separation of the explosion-proof valve 40 from the first end wall 11 is relatively small, thereby improving the opening ability of the explosion-proof valve 40, which is beneficial to the pressure relief of the cylindrical battery.

[0045] At least part of the first orthographic projection is located inside the area enclosed by the second orthographic projection, that is, at least part of the first orthographic projection is located within the range of the area enclosed by the inner contour of the second orthographic projection, which actually means that at least part of the first orthographic projection is located on one side of the inner contour of the second orthographic projection close to the center.

[0046] The explosion-proof valve 40 is arranged around the pole assembly 30, for example, in combination with Figure 1 and Figure 3B As shown, the explosion-proof valve 40 can be arranged around the entire circumference of the pole assembly 30. In this case, the area enclosed by the second orthographic projection can be a circle, and at least part of the first orthographic projection is located within the circle, that is, Figure 3B Generally speaking, the weak area 51 is located in the area enclosed by the inner contour of the explosion-proof valve 40; or, the explosion-proof valve 40 can be arranged around half of the pole assembly 30. In this case, the area enclosed by the second orthographic projection can be a semicircle, and at least part of the first orthographic projection is located in the semicircle; or, the explosion-proof valve 40 can be arranged around more than half of the pole assembly 30, etc.

[0047] In one embodiment, along the radial direction of the first end wall 11, the distance between the outer contours on both sides of the first orthographic projection is greater than the distance between the outer contours on both sides of the second orthographic projection, that is, along the radial direction of the first end wall 11, the width dimension of the weak area 51 can be greater than the width dimension of the explosion-proof valve 40, which is conducive to breaking open the weak area 51 of the insulating member 50, ensuring that the gas reaches the explosion-proof valve 40, and then forming a reliable pressure relief of the cylindrical battery.

[0048] In one embodiment, the total area of ​​the first orthographic projection is greater than the total area of ​​the second orthographic projection, thereby ensuring that the weak area 51 can be reliably disconnected, minimizing the impact of pressure release during battery thermal runaway, thereby improving the safe use performance of the battery.

[0049] In one embodiment, Figure 3A As shown, the first orthographic projection overlaps with a portion of the second orthographic projection, and along the radial direction of the first end wall 11, the outer contours on the opposite sides of the first orthographic projection are spaced apart from the outer contours on the opposite sides of the second orthographic projection, so that the explosion-proof valve 40 and the weak area 51 can be spatially overlapped to the greatest extent, and then when the weak area 51 is disconnected, the gas can be released from the explosion-proof valve 40 in time, thereby improving the safety protection capability of the explosion-proof valve 40.

[0050] It should be noted that, combined with Figure 3A As shown, along the radial direction X of the first end wall 11 , the outer contours of the opposite sides of the first orthographic projection can be considered as the opposite sides of the weak area 51 , and correspondingly, the outer contours of the opposite sides of the second orthographic projection are the inner and outer circles of the explosion-proof valve 40 .

[0051] In one embodiment, the explosion-proof valve 40 is a notch, which is not only simple in structure but also helps to improve the molding efficiency of the cylindrical battery. The cylindrical battery can explode from the notch to achieve gas discharge.

[0052] The explosion-proof valve 40 is a notch, which reduces the local thickness of the first end wall 11, thereby facilitating the explosion of the notch.

[0053] The notches may be formed by removing material, or the notches may be formed by reducing the thickness by extrusion, etc., which is not limited here.

[0054] In one embodiment, the explosion-proof valve 40 may be a structure independent of the first end wall 11 . For example, the explosion-proof valve 40 may be welded to the first end wall 11 , or the explosion-proof valve 40 may be bonded to the first end wall 11 .

[0055] In one embodiment, the explosion-proof valve 40 is disposed around the entire circumference of the pole assembly 30, so that the explosion-proof valve 40 is a circumferentially closed structure, so that after the explosion-proof valve 40 explodes, it can have a relatively large explosion area, thereby improving the pressure relief capacity.

[0056] When the explosion-proof valve 40 is notched, after the explosion-proof valve 40 explodes, the portion of the first end wall 11 in the middle of the explosion-proof valve 40 will be detached. At this time, the insulating member 50 is disconnected from the weak area 51, which is more conducive to the separation of the portion of the first end wall 11 in the middle of the explosion-proof valve 40, thereby improving the pressure relief capacity.

[0057] It should be noted that, in some embodiments, it is not excluded that the explosion-proof valve 40 is disposed around the pole assembly 30 but not around the entire circumference.

[0058] In one embodiment, the weak area 51 includes a through hole; wherein, there are multiple through holes, and the multiple through holes are spaced around the pole assembly 30, and a connection area 52 is formed between adjacent through holes, and the connection area 52 is the area between the opposite sides of the adjacent through holes, and the orthographic projection of the connection area 52 onto the plane where the first end wall 11 is located is the third orthographic projection, and the ratio of the total area of ​​the third orthographic projection to the sum of the total area of ​​the first orthographic projection and the total area of ​​the third orthographic projection is a, the capacity of the cylindrical battery is b, and a×b is 2Ah-25Ah, so that it can be ensured that when the explosion-proof valve 40 is opened, the connection area 52 can be disconnected, thereby ensuring the rapid separation between the explosion-proof valve 40 and the first end wall 11, thereby ensuring that the cylindrical battery is depressurized in time.

[0059] Combination Figure 3A and Figure 3B As shown, the weak area 51 may include a plurality of through holes, and the plurality of through holes are spaced around the pole assembly 30, so that a connection area 52 may be formed between adjacent through holes. Due to the presence of the through holes, the structural strength of the connection area 52 may be weakened, so that when the explosion-proof valve 40 is opened, the connection area 52 may be disconnected, thereby achieving rapid separation between the explosion-proof valve 40 and the first end wall 11.

[0060] A connection area 52 is formed between adjacent through holes. The connection area 52 is the area between the opposite sides of the adjacent through holes. The four side walls of the connection area 52 can be the opposite sides of the two adjacent through holes, and the line between the outer contours of the two adjacent through holes along the radial direction of the first end wall 11. Figure 3B As shown, the connection area 52 is the area enclosed by the two dotted lines and the opposite sides of two adjacent through holes, and the two dotted lines may be arcs. Figure 3A and 3B For example, the plurality of through holes and the plurality of connection areas 52 substantially form a circular ring structure.

[0061] Alternatively, if the shape of the through hole is substantially rectangular, the shape of the connection area 52 formed between two adjacent through holes is also substantially rectangular.

[0062] The sum of the total area of ​​the first orthographic projection and the total area of ​​the third orthographic projection is the total area of ​​the area where the weak area 51 and the connecting area 52 are located, and the ratio of the total area of ​​the third orthographic projection to the sum of the total area of ​​the first orthographic projection and the total area of ​​the third orthographic projection is a, which is the proportion of the total area of ​​the area where the connecting area 52 occupies the weak area 51 and the connecting area 52.

[0063] The capacity of the cylindrical battery is b. The larger the capacity b of the cylindrical battery, the greater the gas production during the battery charging and discharging process, and the smaller the area of ​​the connection area 52 is controlled, which is conducive to disconnecting the insulating member 50 when the heat inside the battery is too large, and the gas is released quickly; by making the product of the capacity b of the cylindrical battery and the ratio a of the total area of ​​the third orthographic projection to the total area of ​​the first orthographic projection and the total area of ​​the third orthographic projection to be 2Ah-25Ah, it can be avoided that the battery capacity is too small, or the area of ​​the connection area 52 is too small, resulting in too low strength of the insulating member 50, and the influence of the insulating member 50 on the explosion of the explosion-proof valve 40 can also be reduced. The product of the capacity b of the cylindrical battery and the ratio a of the total area of ​​the third orthographic projection to the total area of ​​the first orthographic projection and the total area of ​​the third orthographic projection should not be too small. If it is too small, the connection area 52 will be too small, which will easily cause the structural strength of the insulating member 50 to be too low. The product of the ratio a of the total area of ​​the third orthographic projection to the sum of the total area of ​​the first orthographic projection and the total area of ​​the third orthographic projection and the capacity b of the cylindrical battery can be 2Ah, 2.5Ah, 3Ah, 3.5Ah, 4Ah, 4.5Ah, 5Ah, 5.5Ah, 6Ah, 6.5Ah, 7Ah, 7.5Ah, 8Ah, 8.5Ah, 9Ah, 9.5Ah, 10Ah, 11Ah, 12Ah, 13Ah, 14Ah, 14.5Ah, 15Ah, 15.5Ah, 16Ah, 16.5Ah, 17Ah, 17.5Ah, 18Ah, 18.5Ah, 19Ah, 19.5Ah, 20Ah, 21Ah, 22Ah, 23Ah, 24Ah, 24.5Ah or 25Ah, etc.

[0064] The ratio a of the total area of ​​the third orthographic projection to the sum of the total area of ​​the first orthographic projection and the total area of ​​the third orthographic projection may be 0.1, 0.15, 2, 0.25, 0.3, 0.35, 4, 0.45, 0.5, 0.55 or 0.6, etc.

[0065] In one embodiment, the weak area 51 includes a through hole; wherein, there are multiple through holes, and the multiple through holes are spaced around the pole assembly 30, and a connection area 52 is formed between adjacent through holes, and the connection area 52 is the area between the opposite sides of the adjacent through holes, and the orthographic projection of the connection area 52 onto the plane where the first end wall 11 is located is the third orthographic projection, and the ratio of the total area of ​​the first orthographic projection to the sum of the total area of ​​the first orthographic projection and the total area of ​​the third orthographic projection is 0.1-2 / 3. On the basis of ensuring that the insulating member 50 can have reliable structural strength, it does not affect the normal explosion of the explosion-proof valve 40 when the battery has thermal runaway, thereby reliably improving the safety performance of the cylindrical battery.

[0066] The ratio of the total area of ​​the first orthographic projection to the sum of the total area of ​​the first orthographic projection and the total area of ​​the third orthographic projection can be 0.1, 0.12, 0.14, 0.15, 0.18, 0.2, 0.22, 0.24, 0.25, 0.28, 0.3, 0.32, 0.34, 0.35, 0.38, 0.4, 0.42, 0.44, 0.45, 0.48, 0.5, 0.52, 0.54, 0.55, 0.58, 0.6, 0.61, 0.62, 0.63, 0.64, 0.65, 0.66 or 2 / 3, etc.

[0067] It should be noted that the total area of ​​the first orthographic projection is the total area of ​​the plurality of through holes, and correspondingly, the total area of ​​the third orthographic projection is the total area of ​​the plurality of connection regions 52 .

[0068] In one embodiment, the wall thickness of the connection area 52 is c, the capacity of the cylindrical battery is b, and c×b is 10 (mm×Ah)-60 (mm×Ah), so that the connection area 52 can be disconnected during the opening of the explosion-proof valve 40, thereby ensuring the pressure relief capacity of the cylindrical battery.

[0069] The wall thickness c of the connection area 52 between adjacent through holes determines the resistance of the insulating member 50 to explosion. If the thickness is thicker, the connection area 52 is difficult to disconnect. When the capacity of the cylindrical battery is relatively large, the wall thickness c of the connection area 52 can be made smaller to ensure normal explosion of the cylindrical battery.

[0070] Combination Figure 4 As shown, the wall thickness of the connecting area 52 can be expressed as c. The wall thickness c of the connecting area 52 can be 0.4mm-1.5mm. The wall thickness c of the connecting area 52 can be 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm or 1.5mm, etc.

[0071] The product of the wall thickness c of the connecting region 52 and the capacity b of the cylindrical battery can be 10 (mm×Ah), 11 (mm×Ah), 12 (mm×Ah), 13 (mm×Ah), 14 (mm×Ah), 15 (mm×Ah), 16 (mm×Ah), 17 (mm×Ah), 18 (mm×Ah), 19 (mm×Ah), 20 (mm×Ah), 21 (mm×Ah), 22 (mm×Ah), 23 (mm×Ah), 24 (mm×Ah), 25 (mm×Ah), 26 (mm×Ah), 27 (mm×Ah), 28 (mm×Ah), 29 (mm×Ah), 30 (mm×Ah), 31 (mm×Ah), 32 (mm×Ah), 33 (mm×Ah), 34 (mm×Ah), m×Ah), 35(mm×Ah), 36(mm×Ah), 37(mm×Ah), 38(mm×Ah), 39(mm×Ah), 40(mm×Ah), 41(mm×Ah), 42(mm×Ah), 43(mm×Ah), 44(mm×Ah), 45(mm×Ah), 46(mm×Ah), 47(mm×Ah), 48(mm×Ah), 49(mm×Ah), 50(mm×Ah), 51(mm×Ah), 52(mm×Ah), 53(mm×Ah), 54(mm×Ah), 55(mm×Ah), 56(mm×Ah), 57(mm×Ah), 58(mm×Ah), 59(mm×Ah) or 60(mm×Ah), etc.

[0072] In one embodiment, Figure 3A and Figure 3B As shown, the insulating member 50 includes a middle portion 53 and an edge portion 54, wherein the middle portion 53 is located on the inner side of the edge portion 54, and the connecting area 52 connects the middle portion 53 and the edge portion 54 to form a through hole between the middle portion 53 and the edge portion 54; wherein the outermost contour of the edge portion 54 is circular, and the pole assembly 30 is arranged to pass through the middle portion 53, thereby facilitating the pole assembly 30 to form an electrical connection with the pole ear of the battery cell, and the outermost contour of the edge portion 54 can be circular, and can also adapt to the internal space of the battery housing 10, which is not only convenient for molding, but also not easy to interfere with other structures, thereby facilitating the installation of the insulating member 50.

[0073] A portion of the middle portion 53 of the insulating member 50 may be inserted into the pole through hole on the first end wall 11, thereby forming insulation protection between the first end wall 11 and the pole assembly 30. The battery housing 10 is a metal housing, for example, the battery housing 10 is an aluminum housing, in which case the battery housing 10 may be electrically connected to the positive electrode tab, or the battery housing 10 is a steel housing, in which case the battery housing 10 may be electrically connected to the negative electrode tab.

[0074] The ratio of the total area of ​​the first orthographic projection to the area enclosed by the outermost contour of the orthographic projection of the middle part 53 on the plane where the first end wall 11 is located can be 0.03-0.5. The middle part 53 has a large area, a large flow rate, a large heat generation, and a larger through hole, which is convenient for timely breaking the insulating part, and the heat reaches the explosion-proof valve 40 and is released in time, thereby ensuring the safe use performance of the cylindrical battery.

[0075] The ratio of the total area of ​​the first orthographic projection to the area enclosed by the outermost contour of the orthographic projection of the middle portion 53 on the plane facing the first end wall 11 can be 0.03, 0.035, 0.04, 0.045, 0.05, 0.055, 0.06, 0.065, 0.07, 0.075, 0.08, 0.085, 0.09, 0.095, 0.11, 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45 or 0.5, etc.

[0076] The insulating member 50 includes a middle portion 53, an edge portion 54, and a connection region 52. The plurality of connection regions 52 form a connection between the middle portion 53 and the edge portion 54. The middle portion 53 is the portion inside the plurality of through holes and the plurality of connection regions 52, and the edge portion 54 is the portion outside the plurality of through holes and the plurality of connection regions 52. Figure 3B As shown, multiple through holes and multiple connecting areas 52 basically form a circular ring structure, and the middle part 53 is the area enclosed by the inner circle of the circular ring structure. The area enclosed by the outermost contour of the positive projection of the middle part 53 onto the plane where the first end wall 11 is located is the inner circle area of ​​the circular ring structure. During specific measurement, the diameter of the inner circle of the circular ring structure can be directly measured, that is, the area size can be calculated. Of course, visual equipment can also be used to measure the area, which is not limited here.

[0077] In one embodiment, the wall thickness of the weak area 51 is d, the capacity of the cylindrical battery is b, and d×b is 10 (mm×Ah)-40 (mm×Ah), thereby ensuring that the weak area 51 can form a quick disconnection when the explosion-proof valve 40 is opened, thereby reducing the obstruction to the explosion-proof valve 40 and improving the separation ability between the explosion-proof valve 40 and the first end wall 11.

[0078] Combination Figure 5 As shown, the wall thickness of the weak area 51 can be expressed as d. The wall thickness d of the weak area 51 can be 0.1mm-0.6mm. The wall thickness d of the weak area 51 can be 0.1mm, 0.15mm, 0.2mm, 0.25mm, 0.3mm, 0.35mm, 0.4mm, 0.45mm, 0.5mm, 0.55mm or 0.6mm, etc.

[0079] The product of the wall thickness d of the weak area 51 and the capacity b of the cylindrical battery can be 10 (mm×Ah), 11 (mm×Ah), 12 (mm×Ah), 13 (mm×Ah), 14 (mm×Ah), 15 (mm×Ah), 16 (mm×Ah), 17 (mm×Ah), 18 (mm×Ah), 19 (mm×Ah), 20 (mm×Ah), 21 (mm×Ah), 22 (mm×Ah), 23 (mm×Ah), 24 (mm×Ah), m×Ah), 25(mm×Ah), 26(mm×Ah), 27(mm×Ah), 28(mm×Ah), 29(mm×Ah), 30(mm×Ah), 31(mm×Ah), 32(mm×Ah), 33(mm×Ah), 34(mm×Ah), 35(mm×Ah), 36(mm×Ah), 37(mm×Ah), 38(mm×Ah), 39(mm×Ah) or 40(mm×Ah), etc.

[0080] It should be noted that the capacity test method of the cylindrical battery can be: charge the cylindrical battery at 0.33C to 100% SOC (State of Charge), then discharge it at 0.1C to 0% SOC, and the discharged capacity is the capacity of the battery.

[0081] Specifically, for different battery systems, the steps of charging to 100% SOC and discharging to 0% SOC may be different:

[0082] The lithium iron phosphate battery is charged at 0.33C to a cut-off voltage of 3.65V, with a cut-off current less than or equal to 0.05C; and discharged to a lower limit voltage of 2.5V.

[0083] The ternary lithium battery is charged at 0.33C to a cut-off voltage of 4.25V, the cut-off current is less than or equal to 0.05C, and discharged to a lower limit voltage of 2.75V.

[0084] In one embodiment, the weak area 51 is arranged around the pole assembly 30; wherein the weak area 51 is arranged around the entire circumference of the pole assembly 30, that is, the weak area 51 is a whole circle thinning structure, which is beneficial to reduce the valve opening pressure b of the explosion-proof valve 40 and facilitate the disconnection of the insulating member 50.

[0085] In one embodiment, the weak area 51 is arranged around the pole assembly 30; wherein the weak area 51 includes a plurality of segmented areas spaced apart around the pole assembly 30, that is, there are also connecting area segments between the weak areas 51, and the wall thickness of the connecting area segments can be greater than the wall thickness d of the weak area 51, thereby requiring a relatively large valve opening pressure b of the explosion-proof valve 40.

[0086] In one embodiment, at least a portion of the insulating member 50 is inclined relative to the large surface of the first end wall 11, and the angle r between the insulating member 50 and the large surface of the first end wall 11 is 2°-15°. On the basis of ensuring the internal space utilization of the battery housing 10, it is also beneficial for the insulating member 50 to be disconnected, thereby reducing the resistance to the separation of the explosion-proof valve 40.

[0087] The large surface of the first end wall 11 is the surface with the largest area of ​​the first end wall 11. The large surface of the first end wall 11 is perpendicular to the axial direction of the cylindrical battery. The angle between the insulating member 50 and the large surface of the first end wall 11 can be considered as the angle between the insulating member 50 and the reference plane parallel to the large surface of the first end wall 11. Figure 4 As shown, the angle between the insulating member 50 and the large surface of the first end wall 11 can be expressed as r, and the angle r between the insulating member 50 and the large surface of the first end wall 11 can be 2°, 2.5°, 3°, 3.5°, 4°, 4.5°, 5°, 5.5°, 6°, 6.5°, 7°, 7.5°, 8°, 8.5°, 9°, 9.5°, 10°, 10.5°, 11°, 11.5°, 12°, 12.5°, 13°, 13.5°, 14°, 14.5° or 15°, etc.

[0088] At least a portion of the insulating member 50 is tilted relative to the large surface of the first end wall 11. When the cylindrical battery explodes, the insulating member 50 is more likely to break off near the weak area 51. This ensures that when the battery explodes, the insulating member 50 is easy to break off, thereby not blocking the separation of the middle area surrounded by the explosion-proof valve 40 from the first end wall 11. However, the angle between the insulating member 50 and the large surface of the first end wall 11 should not be too large, so as to save the height space of the cylindrical battery.

[0089] In one embodiment, at least a portion of the insulating member 50 is arranged with a large surface from its edge to its center gradually away from the first end wall 11, that is, the edge of the insulating member 50 can be closer to the first end wall 11, and the insulating member 50 is easier to disconnect when the explosion-proof valve 40 opens.

[0090] Combination Figure 4 and Figure 5 As shown, a portion of the insulating member 50 can be arranged from its edge to its middle portion gradually away from the large surface of the first end wall 11, that is, the edge of the insulating member 50 is closer to the first end wall 11, and the middle portion of the edge away from the insulating member 50 can be arranged slightly away from the large surface of the first end wall 11, thereby making a portion of the insulating member 50 inclined relative to the large surface of the first end wall 11.

[0091] In one embodiment, the first end wall 11 is a cover plate, and the second end wall 12 and the side wall 13 are an integrally formed structure, which not only facilitates the arrangement of the pole assembly 30 on the first end wall 11, but also facilitates the forming of the explosion-proof valve 40, thereby improving the manufacturing efficiency of the cylindrical battery.

[0092] The first end wall 11 may be connected to the side wall 13 by welding.

[0093] It should be noted that, in some embodiments, it is not excluded that the first end wall 11 and the second end wall 12 are both independent components relative to the side wall 13; or, the first end wall 11 and the side wall 13 are an integrally formed structure, and the second end wall 12 is a cover plate, that is, the second end wall 12 is an independent component.

[0094] An embodiment of the utility model further provides a battery pack, comprising the above-mentioned cylindrical battery.

[0095] The cylindrical battery of the battery pack of one embodiment of the utility model comprises a battery case 10, a battery cell 20, a pole assembly 30, an explosion-proof valve 40 and an insulating member 50. The battery cell 20 is arranged in the battery case 10, the pole assembly 30 is arranged on the first end wall 11 of the battery case 10, the pole assembly 30 is electrically connected to the battery cell 20, and the explosion-proof valve 40 is arranged on the first end wall 11 around the pole assembly 30, so that after the internal pressure of the battery case 10 reaches a certain height, the explosion-proof valve 40 can explode, thereby forming an internal pressure release. At least part of the insulating member 50 is located between the first end wall 11 and the battery cell 20, thereby ensuring the insulation capacity between the first end wall 11 and the battery cell 20, and avoiding the risk of causing a short circuit. By providing a weak area 51 on the insulating member 50, the weak area 51 and the orthographic projection of the explosion-proof valve 40 on the plane where the first end wall 11 is located are respectively the first orthographic projection and the second orthographic projection, and at least part of the first orthographic projection and the second orthographic projection overlap, or, along the radial direction of the first end wall 11, the distance between the first orthographic projection and the second orthographic projection is k, 0<k≤5mm, so as to avoid obstruction by the insulating member 50, resulting in the inability of the gas to quickly reach the explosion-proof valve 40 area, affecting the separation of the explosion-proof valve 40 and the first end wall 11. Therefore, when the cylindrical battery explodes, the insulating member 50 can also be disconnected near the weak area 51, thereby reducing the obstruction to the separation of the intermediate explosion-proof valve 40 and the first end wall 11, ensuring normal pressure relief, and further ensuring the safe use performance of the cylindrical battery.

[0096] In one embodiment, the battery pack is a battery module or a battery pack. The battery pack may include a plurality of cylindrical batteries.

[0097] Those skilled in the art will readily come up with other embodiments of the present disclosure after considering the specification and practicing the utility model disclosed herein. The present disclosure is intended to cover any variation, use or adaptation of the present utility model, which follows the general principles of the present disclosure and includes common knowledge or customary technical means in the art that are not disclosed in the present disclosure. The specification and example embodiments are to be regarded as exemplary only, and the true scope and spirit of the present disclosure are indicated by the appended claims.

[0098] It should be understood that the present disclosure is not limited to the precise structures that have been described above and shown in the drawings, and that various modifications and changes may be made without departing from its scope. The scope of protection of the present disclosure is limited only by the appended claims.

Claims

1. A cylindrical battery, characterized in that: include: A battery housing (10), the battery housing (10) comprising a first end wall (11), a second end wall (12) and a side wall (13), wherein the first end wall (11) and the second end wall (12) are respectively connected to opposite ends of the side wall (13); A battery cell (20), wherein the battery cell (20) is arranged in the battery casing (10); A pole assembly (30), the pole assembly (30) being arranged on the first end wall (11) and electrically connected to the battery core (20); an explosion-proof valve (40), the explosion-proof valve (40) being arranged on the first end wall (11) and surrounding the pole assembly (30); an insulating member (50), wherein at least a portion of the insulating member (50) is located inside the battery housing (10) and between the first end wall (11) and the battery core (20), and an area enclosed by an outermost contour of the insulating member (50) is larger than an area enclosed by an outermost contour of the explosion-proof valve (40); The insulating member (50) is provided with a weak area (51), and the weak area (51) and the orthographic projection of the explosion-proof valve (40) on the plane where the first end wall (11) is located are respectively a first orthographic projection and a second orthographic projection, and the first orthographic projection at least partially overlaps with the second orthographic projection, or, along the radial direction of the first end wall (11), the distance between the first orthographic projection and the second orthographic projection is k, 0<k≤5mm.

2. The cylindrical battery according to claim 1, characterized in that: At least a portion of the first orthographic projection is located inside an area enclosed by the second orthographic projection.

3. The cylindrical battery according to claim 1, characterized in that: Along the radial direction of the first end wall (11), the distance between the outer contours on two opposite sides of the first orthographic projection is greater than the distance between the outer contours on two opposite sides of the second orthographic projection.

4. The cylindrical battery according to claim 1, characterized in that: The first orthographic projection overlaps with a portion of the second orthographic projection, and along the radial direction of the first end wall (11), the outer contours on opposite sides of the first orthographic projection are spaced apart from the outer contours on opposite sides of the second orthographic projection.

5. The cylindrical battery according to claim 1, characterized in that: The weak area (51) comprises a through hole; There are a plurality of through holes, and the plurality of through holes are spaced apart around the pole assembly (30), and a connection area (52) is formed between adjacent through holes, and the connection area (52) is an area between opposite sides of adjacent through holes, and the orthographic projection of the connection area (52) onto the plane where the first end wall (11) is located is a third orthographic projection, and the ratio of the total area of ​​the first orthographic projection to the sum of the total area of ​​the first orthographic projection and the total area of ​​the third orthographic projection is 0.1-2 / 3.

6. The cylindrical battery according to claim 1, characterized in that: The weak area (51) comprises a through hole; There are a plurality of through holes, and the plurality of through holes are spaced around the pole assembly (30), and a connection area (52) is formed between adjacent through holes, and the connection area (52) is an area between opposite sides of adjacent through holes, and the orthographic projection of the connection area (52) onto the plane where the first end wall (11) is located is a third orthographic projection, and the ratio of the total area of ​​the third orthographic projection to the sum of the total area of ​​the first orthographic projection and the total area of ​​the third orthographic projection is a, and the capacity of the cylindrical battery is b, and a×b is 2Ah-25Ah.

7. The cylindrical battery according to claim 5 or 6, characterized in that: The wall thickness of the connection area (52) is c, the capacity of the cylindrical battery is b, and c×b is 10 (mm×Ah)-60 (mm×Ah).

8. The cylindrical battery according to claim 5 or 6, characterized in that: The insulating member (50) comprises a middle portion (53) and an edge portion (54), the middle portion (53) is located inside the edge portion (54), and the connecting region (52) connects the middle portion (53) and the edge portion (54) to form the through hole between the middle portion (53) and the edge portion (54); The pole assembly (30) is arranged to pass through the middle part (53), and the ratio of the total area of ​​the first orthographic projection to the area enclosed by the outermost contour of the orthographic projection of the middle part (53) on the plane where the first end wall (11) is located is 0.03-0.

5.

9. The cylindrical battery according to claim 1, characterized in that: The wall thickness of the weak area (51) is d, the capacity of the cylindrical battery is b, and d×b is 10 (mm×Ah)-40 (mm×Ah).

10. The cylindrical battery according to claim 9, characterized in that: The weak area (51) is arranged around the pole assembly (30); The weak area (51) is arranged around the entire circumference of the pole assembly (30), or the weak area (51) includes a plurality of segmented areas arranged at intervals around the pole assembly (30).

11. The cylindrical battery according to claim 1, characterized in that: At least part of the insulating member (50) is arranged obliquely relative to the large surface of the first end wall (11), and an angle r between the insulating member (50) and the large surface of the first end wall (11) is 2°-15°; Wherein, at least a portion of the insulating member (50) is arranged with a large surface that gradually moves away from the first end wall (11) from its edge to its middle.

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