Battery

Abstract

The invention relates to the technical field of batteries, and particularly discloses a battery, a cover plate body or a shell of the battery is provided with a mounting hole and a supporting structure, an anti-explosion valve is arranged in the mounting hole, the supporting structure comprises a first supporting table and a supporting plate connected with the first supporting table, and an exhaust space is formed between the supporting plate and the cover plate body or the shell; and the exhaust space is communicated with a pressure relief channel of the anti-explosion valve. An exhaust gap is formed between the side, facing the cover plate body or the shell, of the first side face of the supporting plate and the end face, facing the supporting plate, of the cover plate body or the shell, a plurality of exhaust holes are formed in the supporting plate, and the exhaust gap and the exhaust holes communicate with the containing cavity and the exhaust space. Therefore, after the battery is subjected to thermal runaway and the plastic part is melted, the supporting structure can continuously support the pole group, so that the mounting hole is prevented from being shielded by the pole group, high-temperature and high-pressure gas can enter the exhaust space from the exhaust gap or the exhaust hole and then is quickly and directionally exhausted through the pressure relief channel of the anti-explosion valve, and the safety of the battery is high.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and particularly to a battery. Background Art

[0002] Lithium-ion batteries have become representatives of high-performance batteries due to their advantages such as high working voltage, high specific energy, large capacity, small self-discharge, good cycle performance, long service life, light weight, and small volume. The structure of a conventional lithium-ion battery includes a cover body, a housing, an electrode assembly, and an insulating member. After the cover body and the housing are welded, a sealed space for protecting the electrode assembly is formed. An explosion-proof valve is integrated on the cover body, and the explosion-proof valve can direct the discharge of high-temperature and high-pressure gas in the sealed space when the battery undergoes thermal runaway. The insulating member is arranged in the sealed space formed by the housing and the cover body, and the insulating member is located between the cover body and the electrode assembly. On the one hand, the electrode assembly can be supported by the insulating member to avoid the electrode assembly shaking in the housing, and the fixing effect is good; on the other hand, the insulating member can prevent the electrode assembly from short-circuiting with the cover body and ensure the electrical safety of the battery.

[0003] However, the insulating member is generally made of a plastic material (for example, PP material), and its strength and high-temperature resistance are limited, and it will generally melt at about 150°C. When the battery undergoes thermal runaway, the temperature in the sealed space is relatively high, and the insulating member will melt and fail. At this time, only the still-solid electrode assembly remains in the sealed space, the gap between the electrode assembly and the cover body increases, and due to the lack of the supporting effect of the insulating member on the electrode assembly, the degree of freedom of the electrode assembly in the housing is relatively high. When the high-temperature and high-pressure gas is discharged directionally through the explosion-proof valve, the electrode assembly will move with the high-temperature and high-pressure gas flow, there is a risk of blocking the exhaust passage of the explosion-proof valve, reducing the exhaust efficiency of the explosion-proof valve and having low safety performance. Summary of the Invention

[0004] The purpose of the present invention is to provide a battery, which can avoid the situation that the explosion-proof valve is blocked due to the movement of the electrode assembly when the battery undergoes thermal runaway, and the explosion-proof valve has a relatively high exhaust efficiency and good safety performance.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] On the one hand, the present invention provides a battery, including:

[0007] A cover body and a housing, the cover body is connected to the housing and encloses to form a receiving cavity, and at least one of the cover body and the housing is provided with a mounting hole and a supporting structure. The mounting hole is used for mounting an explosion-proof valve, and a pressure relief channel is formed after the explosion-proof valve is opened;

[0008] The support structure includes two first support platforms and a support plate, the two first support platforms are arranged on both sides of the mounting hole along the first direction, the two ends of the support plate along the first direction are respectively connected to one of the first support platforms, an exhaust space is formed between the support plate and the cover plate body or the shell, and the exhaust space is communicated with the pressure relief channel;

[0009] The support plate has two first side surfaces that are arranged opposite to each other along the second direction, and a gas exhaust gap is formed between a side of each of the first side surfaces that faces the cover plate body or the shell and an end surface of the cover plate body or the shell that faces the support plate, and the gas exhaust gap connects the accommodating cavity with the gas exhaust space; a plurality of gas exhaust holes are provided on the support plate, and the plurality of gas exhaust holes penetrate the support plate along the third direction, and the gas exhaust holes connect the accommodating cavity with the gas exhaust space;

[0010] The sum of the flow areas of all the exhaust gaps is S11, the sum of the flow areas of all the exhaust holes is S12, S1=S11+S12; the flow area of the pressure relief channel is S2;

[0011] S1 and S2 satisfy: 2.0≤S1 / S2≤4.0;

[0012] The value range of S2 is: 260mm 2 ≤S2≤1100mm 2 .

[0013] Optionally, the relationship between the sum of the flow areas of all the exhaust gaps S11 and the sum of the flow areas of all the exhaust holes S12 satisfies: 0.25≤S12 / S1≤0.50;

[0014] The value range of S12 is: 400mm 2 ≤S12≤1600mm 2 .

[0015] Optionally, the battery further comprises a plastic part, which is arranged on a side of the cover body or the shell close to the accommodating cavity, and the plastic part abuts against an end surface of the support plate facing away from the cover body or the shell.

[0016] Optionally, some of the multiple exhaust holes are first exhaust holes, and the projection of the first exhaust holes on the cover body or the shell along the third direction at least partially overlaps with the explosion-proof valve, and the remaining exhaust holes are second exhaust holes, and the second exhaust holes are arranged in an array on the support plate.

[0017] Optionally, the second exhaust hole is a square hole, a side length of the square hole is a1, and a value range of a1 is 3mm≤a1≤10mm.

[0018] Optionally, on the sides of the two first support platforms spaced along the first direction facing away from each other, they are respectively flush with one end of the support plate along the first direction, and on the sides of the support plate facing away from each other along the second direction, they are respectively flush with one end of the first support platform along the second direction;

[0019] Wherein, the length of the support plate along the first direction is B, the width of the first support platform along the first direction is W2; the height of the first support platform along the third direction is H;

[0020] The calculation formula of S11 is:

[0021] S11 = 2*(B - 2*W2)*H;

[0022] The value range of B is 100mm ≤ B ≤ 180mm;

[0023] The value range of W2 is 5mm ≤ W2 ≤ 10mm;

[0024] The value range of H is 1.5mm ≤ H ≤ 3.0mm.

[0025] Optionally, the support structure further includes two second support platforms, each second support platform is clamped between one first support platform and the mounting hole, and the side of the second support platform facing away from the cover body or the housing is connected to the support plate.

[0026] Optionally, the contact area between each first support platform and the support plate is S31, the contact area between each second support platform and the support plate is S32, and the total contact area between the support plate and the first support platform and the second support platform is S3;

[0027] The calculation formula of S3 is:

[0028] S3 = 2*S31 + 2*S32;

[0029] The value range of S3 is 700mm 2 ≤ S3 ≤ 2500mm 2 .

[0030] Optionally, the explosion-proof valve includes a fixing part and a body part, the fixing part is disposed around the circumference of the body part, a scoring groove is provided on the body part, the part surrounded by the scoring groove forms an opening part, the circumferential side of the fixing part is in contact with and welded to the inner wall of the mounting hole, and the area of the opening part is equal to the area of the pressure relief channel;

[0031] The total area of the explosion-proof valve is S0, and S0 and S2 satisfy: 0.80 ≤ S2 / S0 ≤ 0.90.

[0032] Optionally, the outer circumference of the explosion-proof valve includes two arc segments and two straight segments. The two straight segments are arranged opposite to each other in the first direction, and the two arc segments are arranged opposite to each other in the second direction, and the two arc segments can form a complete circle;

[0033] The calculation formula of S0 is:

[0034]

[0035] Wherein, the distance between the two straight segments in the first direction is W1, and the distance between the mutually departing end points of the two arc segments in the second direction is L1;

[0036] The value range of W1 is: 15mm ≤ W1 ≤ 40mm;

[0037] The value range of L1 is: 25mm ≤ L1 ≤ 65mm.

[0038] The beneficial effects of the present invention are:

[0039] The present invention provides a battery, including an explosion-proof valve, a cover body and a housing. The cover body and the housing together form a receiving cavity for placing a pole group. An installation hole and a support structure are provided on the cover body or the housing, and the explosion-proof valve is arranged in the installation hole. The support structure includes two first support platforms and a support plate. The two ends of the support plate in the first direction are respectively connected to a first support platform. An exhaust space is formed between the support plate and the cover body or the housing, and the exhaust space is communicated with the pressure relief channel of the explosion-proof valve. An exhaust gap is formed between the first side of the support plate facing the cover body or the housing and the end face of the cover body or the housing facing the support plate, and the exhaust gap communicates the receiving cavity with the exhaust space. A plurality of exhaust holes penetrating through the support plate are provided on the support plate, and the exhaust holes are communicated with the receiving cavity and the exhaust space.

[0040] Wherein, the sum of the flow areas of all the exhaust gaps is S11, the sum of the flow areas of all the exhaust holes is S12, and S1 = S11 + S12; the flow area of the pressure relief channel is S2, and S1 and S2 satisfy: 2.0 ≤ S1 / S2 ≤ 4.0. Through the above settings, when the battery undergoes thermal runaway and the plastic part is melted, the support structure can continue to support the pole group, preventing the installation hole from being blocked by the pole group, and the total flow area S1 of all the exhaust gaps and all the exhaust holes matches the flow area S2 of the pressure relief channel of the explosion-proof valve, meeting the flow requirements of high-temperature and high-pressure gases. The high-temperature and high-pressure gases can enter the exhaust space from the exhaust gap or the exhaust hole, and then be quickly and directionally discharged through the pressure relief channel of the explosion-proof valve. The explosion-proof valve has a good exhaust effect and the battery has good safety. Description of the Drawings

[0041] To more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments of the present invention. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained according to the content of the embodiments of the present invention and these drawings.

[0042] Figure 1 An exploded view of the cover body and the plastic part provided in the first embodiment of the present invention;

[0043] Figure 2 An exploded view of the cover body provided in the first embodiment of the present invention;

[0044] Figure 3 A top view of the cover body provided in the first embodiment of the present invention;

[0045] Figure 4 A top view of the cover body (when the support plate is not shown) provided in the first embodiment of the present invention;

[0046] Figure 5 A side view of the cover body provided in the first embodiment of the present invention;

[0047] Figure 6 For Figure 5 The partial enlarged view at Ι in

[0048] Figure 7 A structural schematic diagram of the explosion-proof valve provided in the first embodiment of the present invention;

[0049] Figure 8 A structural schematic diagram of the battery provided in the second embodiment of the present invention.

[0050] In the figure:

[0051] 100, cover body; 110, mounting hole; 111, limiting flange; 120, first support platform; 130, second support platform; 140, support plate; 1401, first side; 1411, exhaust gap; 1402, second side; 141, first exhaust hole; 142, second exhaust hole; 200, housing; 201, opening; 210, first side wall; 220, second side wall; 300, plastic part; 301, through hole; 400, explosion-proof valve; 410, fixing part; 411, arc segment; 412, straight segment; 420, body part; 421, scoring groove; 430, opening part. Detailed implementation manners

[0052] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0053] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. Among them, the terms "first position" and "second position" are two different positions. Moreover, the first feature being "above", "over" and "on" the second feature includes the first feature being directly above and obliquely above the second feature, or merely indicating that the first feature has a higher horizontal height than the second feature. The first feature being "under", "below" and "beneath" the second feature includes the first feature being directly below and obliquely below the second feature, or merely indicating that the first feature has a lower horizontal height than the second feature.

[0054] In the description of the present invention, it should be noted that unless otherwise clearly defined and limited, the terms "installed", "connected" and "coupled" shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0055] The embodiments of the present invention will be described in detail below. The examples of the embodiments are shown in the accompanying drawings, in which the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary and are only used to explain the present invention and should not be construed as a limitation of the present invention.

[0056] Embodiment 1

[0057] As Figures 1-4As shown, this embodiment provides a battery, which includes an explosion-proof valve 400, a cover body 100, a shell 200 and a plastic part 300. At least one end of the shell 200 is provided with an opening 201. The cover body 100 is connected to the end of the shell 200 provided with the opening 201 and forms a containing cavity for placing the pole group with the shell 200. The cover body 100 is provided with a mounting hole 110 and a supporting structure. The explosion-proof valve 400 is arranged in the mounting hole 110. After the explosion-proof valve 400 is opened, a pressure relief channel is formed, and the exhaust and pressure relief function of the battery is realized through the pressure relief channel. The plastic part 300 is arranged on a side of the cover body 100 close to the containing cavity, and the plastic part 300 is abutted against a side of the support structure away from the cover body 100, and the cover body 100 is insulated from the pole group by the plastic part 300. The supporting structure includes two first support platforms 120 and a support plate 140. The two first support platforms 120 are arranged in the mounting hole 110 along the first direction ( Figure 1 The support plate 140 is connected to the first support platform 120 at both ends along the first direction, and an exhaust space is formed between the support plate 140 and the cover body 100, and the exhaust space is connected to the pressure relief channel of the explosion-proof valve 400. The end surface of the support plate 140 away from the cover body 100 can abut against the plastic part 300.

[0058] Furthermore, the support plate 140 has two first side surfaces 1401 arranged opposite to each other along the second direction, and a second side surface 1402 arranged opposite to each other along the first direction, the first side surface 1401 and the second side surface 1402 are adjacent to each other, and the first side surface 1401 and the second side surface 1402 together constitute the peripheral side wall of the support plate 140. The second direction is Figure 1 The Y-axis direction shown in is the width direction of the cover body 100. A gas exhaust gap 1411 is formed between the side of each first side surface 1401 facing the cover body 100 and the end surface of the cover body 100 facing the support plate 140. There are two gas exhaust gaps 1411, which are respectively located on the opposite sides of the support plate 140 along the second direction. The gas exhaust gaps 1411 connect the accommodating cavity with the gas exhaust space.

[0059] The support plate 140 is also provided with a plurality of exhaust holes, which penetrate the support plate 140 along the third direction, and the exhaust holes connect the accommodating cavity with the exhaust space. Figure 1The Z-axis direction shown in the figure is also the thickness direction of the cover plate body 100. Thus, when the battery undergoes thermal runaway and the plastic part 300 is melted, the support structure can continue to support the electrode group, preventing the electrode group from blocking the mounting holes 110 on the cover plate body 100. At this time, the battery can relieve pressure through two exhaust paths. One is that the high-temperature and high-pressure gas in the accommodation cavity can be discharged through the exhaust gap 1411, the exhaust space, and the pressure relief channel of the explosion-proof valve 400; the other is that the high-temperature and high-pressure gas in the accommodation cavity can be discharged through the exhaust hole, the exhaust space, and the pressure relief channel of the explosion-proof valve 400. Both the exhaust gap 1411 and the exhaust hole are exhaust channels for the explosion-proof valve 400 to achieve the exhaust function. The high-temperature and high-pressure gas can be quickly and directionally discharged from the exhaust space and the pressure relief channel. The flow path of the high-temperature and high-pressure gas is smooth, the flow velocity is fast, the exhaust effect of the explosion-proof valve 400 is good, and the safety of the battery is high.

[0060] Further, the sum of the flow areas of all the exhaust gaps 1411 is S11, the sum of the flow areas of all the exhaust holes is S12, and the total flow area of all the exhaust gaps 1411 and all the exhaust holes can be denoted as S1, and S1 = S11 + S12. That is to say, the total flow area of the exhaust channels for achieving the exhaust function is S1. The flow area of the pressure relief channel is S2. The relationship between S1 and S2 satisfies: 0.20 ≤ S1 / S2 ≤ 0.40. For example, in some embodiments, the value of S1 / S2 can be 0.20, 0.25, 0.30, 0.35, or 0.40, etc. Thus, it is ensured that the total flow area S1 of the exhaust channels matches the flow area S2 of the pressure relief channel of the explosion-proof valve 400, meeting the flow requirements of the high-temperature and high-pressure gas. The explosion-proof valve 400 can open the valve in time, preventing the pressure in the accommodation cavity from being too high and causing an explosion, with relatively high safety. At the same time, the mechanical strength of the support structure is relatively high, and it is not easy to have deformation problems. The value range of S2 is: 260mm 2 ≤ S2 ≤ 1100mm 2 For example, the value of S2 can be 260mm 2 、300mm 2 、500mm 2 、800mm 2 or 1100mm 2 etc. Correspondingly, the value of S1 can be calculated according to the above value range of S1 / S2.

[0061] Optionally, the relationship between the sum S11 of the flow areas of all the exhaust gaps 1411 and the sum S12 of the flow areas of all the exhaust holes also satisfies: 0.25 ≤ S12 / S1 ≤ 0.50. For example, in some embodiments, the value of S12 / S1 can be 0.25, 0.30, 0.35, 0.40, 0.45, 0.50, etc. Among them, along the third direction, at least part of the exhaust holes are directly opposite to the explosion-proof valve 400, so that the high-temperature and high-pressure gas before the plastic part 300 is melted can directly act on the explosion-proof valve 400, enabling the explosion-proof valve 400 to respond in a timely manner and open the valve quickly to ensure battery safety. After the plastic part 300 is melted, the high-temperature and high-pressure gas can directly pass through the exhaust holes on the support plate 140 and enter the pressure relief channel of the explosion-proof valve 400, which is conducive to achieving rapid pressure relief. It should be noted that the sum S12 of the flow areas of all the exhaust holes should not be too large, otherwise, after multiple exhaust holes are opened on the support plate 140, the mechanical strength will decrease too much, and it is easy to deform when abutting against the electrode group, affecting the exhaust efficiency.

[0062] Meanwhile, the sum S11 of the flow areas of the exhaust gaps 1411 formed on both sides of the support plate 140 along the second direction should not be too small either, otherwise, after the electrode group abuts against the support plate 140, the exhaust space formed between the support plate 140 and the cover body 100 is small, which is also not conducive to the rapid flow of high-temperature and high-pressure gas, and the exhaust efficiency is reduced. It should be noted that the flow area of the exhaust gap 1411 is positively correlated with the volume of the exhaust space formed between the support plate 140 and the cover body 100. When the length of the support plate 140 along the first direction remains unchanged and the width along the second direction also remains unchanged, the height of the first support platform 120 along the third direction determines the size of the flow area of the exhaust gap 1411 and the volume of the exhaust space, and the flow area of the exhaust gap 1411 and the volume of the exhaust space increase or decrease simultaneously.

[0063] Exemplarily, the value range of S12 is: 400mm 2 ≤ S12 ≤ 1600mm 2 For example, the value of S12 can be 400mm 2 、500mm 2 、800mm 2 、1000mm 2 or 1600mm 2 etc. The value of S1 can be calculated according to the above value range of S12 / S1. It should be noted that the value of S1 should also meet the dimensional limitation of S1 / S2.

[0064] Further, among the multiple exhaust holes on the support plate 140, some exhaust holes are first exhaust holes 141. Along the third direction, the projection of the first exhaust holes 141 on the cover body 100 at least partially coincides with the explosion-proof valve 400. The remaining exhaust holes are second exhaust holes 142, and the second exhaust holes 142 are arranged in an array on the support plate 140.

[0065] Optionally, the multiple first exhaust holes 141 are spaced apart on the support plate 140. For example, the first exhaust holes 141 are arranged in three rows along the second direction on the support plate 140, and two first exhaust holes 141 are arranged at intervals in each row. At the position corresponding to the mounting hole 110 on the plastic part 300, a plurality of through holes 301 are arranged at intervals. Along the third direction, the through holes 301 are directly opposite to the explosion-proof valve 400, so that the high-temperature and high-pressure gas can pass through the through holes 301 and the first exhaust holes 141 and directly act on the explosion-proof valve 400 before the plastic part 300 is melted, so that the explosion-proof valve 400 can respond in time and open the valve quickly to ensure the safety of the battery. After the plastic part 300 is melted, the high-temperature and high-pressure gas can pass through the first exhaust holes 141 on the support plate 140 and enter the pressure relief channel of the explosion-proof valve 400 to achieve rapid pressure relief and ensure the safety of the battery. There are also a plurality of second exhaust holes 142, and the plurality of second exhaust holes 142 are arranged in two rows along the second direction, and the plurality of second exhaust holes 142 in each row are spaced apart along the first direction. For example, six second exhaust holes 142 can be arranged in each row, and every three second exhaust holes 142 are a group, and the two groups of second exhaust holes 142 are respectively arranged on both sides of the mounting hole 110 along the first direction. Through the arrangement of the second exhaust holes 142, the flow area of the high-temperature and high-pressure gas flowing along the third direction is increased, which is beneficial to achieving rapid pressure relief.

[0066] As an optional solution, the second exhaust holes 142 in this embodiment are square holes, the side length of the second exhaust holes 142 is a1, and the value range of a1 is 3 mm ≤ a1 ≤ 10 mm. For example, the value of a1 can be 3 mm, 5 mm, 8 mm or 10 mm, etc. Of course, in other embodiments, the shape of the second exhaust holes 142 can also be set as circular holes, triangular holes, rectangular holes, pentagonal holes or hexagonal holes, etc., as long as the flow area of the second exhaust holes 142 is the same as that of the above-mentioned square holes.

[0067] In this embodiment, the shape of the first exhaust hole 141 located in the middle position along the second direction is a square hole, the side length of the square hole is a2, the shapes of the remaining first exhaust holes 141 are sectors, the centers of all the sectors face the center of the explosion-proof valve 400, and the radius of the sectors is a3, and a1 = a2 = a3.

[0068] Further, refer to Figures 3-6, on the mutually facing sides of two first support platforms 120 spaced apart in the first direction, they are respectively flush with one end of the support plate 140 in the first direction, and on the mutually facing sides of the support plate 140 in the second direction, they are respectively flush with one end of the first support platform 120 in the second direction. Among them, the length of the support plate 140 in the first direction is B, the width of the first support platform 120 in the first direction is W2; the height of the first support platform 120 in the third direction is H.

[0069] The calculation formula of S11 is:

[0070] S11 = 2 * (B - 2 * W2) * H.

[0071] The value range of S11 obtained according to the above calculation formula is 450mm 2 ≤ S11 ≤ 1700mm 2 .

[0072] Exemplarily, the value range of B is 100mm ≤ B ≤ 180mm. For example, the value of B can be 100mm, 120mm, 150mm, 160mm or 180mm, etc. And the length of the support plate 140 in the first direction needs to be less than the length of the cover body 100 in the first direction. The length of the cover body 100 in the first direction is A, that is, B < A. Optionally, the value range of A is 120mm ≤ A ≤ 200mm. For example, in some embodiments, the value of A can be 120mm, 150mm, 180mm or 200mm, etc. Thus, it is ensured that there is sufficient installation space on both sides of the cover body 100 in the first direction, and when the cover body 100 is assembled with the housing 200, interference between the support plate 140 and the housing 200 is avoided.

[0073] The value range of W2 is 5mm ≤ W2 ≤ 10mm. For example, the value of W2 can be 5mm, 8mm or 10mm, etc. By limiting the value of W2 within the above range, it can be ensured that the width of the first support platform 120 in the first direction is relatively large, the first support platform 120 is easy to be stamped and formed, and the contact area between the first support platform 120 and the support plate 140 is relatively large, and the support effect on the support plate 140 is better. Otherwise, when the value of W2 is too small, the production yield of the first support platform 120 is relatively low, the cover body 100 is easily broken during stamping, and the support effect of the first support platform 120 on the support plate 140 after production is not good, thus affecting the support effect of the support plate 140 on the electrode group. Of course, the value of W2 should not be too large either, otherwise the flow area of the exhaust gap 1411 is reduced, affecting the exhaust efficiency of high-temperature and high-pressure gases.

[0074] The value range of H is 1.5mm≤H≤3.0mm. For example, the value of H can be 1.5mm, 1.7mm, 2.0mm, 2.5mm or 3.0mm, etc. By limiting the value of H within the above range, the flow area of the exhaust gap 1411 formed between the first side surface 1401 of the support plate 140 facing the cover body 100 and the end surface of the cover body 100 facing the support plate 140 is larger, and the exhaust space between the cover body 100 and the support plate 140 is larger, which is conducive to improving the exhaust efficiency of the explosion-proof valve 400 and has high safety.

[0075] The thickness of the support plate 140 along the third direction is t, and the value range of t is 0.8 mm ≤ t ≤ 2.0 mm. For example, the value of t can be 0.8 mm, 1.2 mm, 1.5 mm, 1.8 mm or 2.0 mm, etc. By limiting the value of t within the above range, the mechanical strength of the support plate 140 is ensured to be high, and the support plate 140 is not easily deformed when it abuts against the pole group, thereby maintaining sufficient exhaust space between the cover plate body 100 and the support plate 140, which facilitates the exhaust of high-temperature and high-pressure gas.

[0076] Furthermore, the support structure further includes two second support platforms 130, each of which is sandwiched between a first support platform 120 and the mounting hole 110, and the second support platform 130 is connected to the support plate 140 on the side away from the cover plate body 100. The second support platform 130 is provided to provide better support for the support plate 140, thereby ensuring that the structure of the support plate 140 is stable, and thus can resist the impact of the pole group on the support plate 140, thereby preventing the explosion-proof valve 400 and the mounting hole 110 from being blocked by the pole group.

[0077] Optionally, the contact area between each first support platform 120 and the support plate 140 is S31, the contact area between each second support platform 130 and the support plate 140 is S32, and the total contact area between the support plate 140 and the first support platform 120 and the second support platform 130 is S3;

[0078] The calculation formula of S3 is:

[0079] S3=2*S31+2*S32.

[0080] The value range of S3 obtained according to the above calculation formula is 700mm 2 ≤S3≤2500mm 2 For example, the value of S3 can be 700mm 2 , 1000mm 2 、1500mm 2 , 2000mm 2 or 2500mm 2By restricting the value of S3 within the above range, it can be ensured that the contact areas between the first supporting platform 120, the second supporting platform 130 and the support plate 140 are relatively large, providing sufficient support for the support plate 140, ensuring that the support plate 140 is not easily deformed, and enabling the smooth exhaust of high-temperature and high-pressure gases. Of course, the value of S3 should not be too large, otherwise the first supporting platform 120 and the second supporting platform 130 will occupy too much exhaust space between the cover plate body 100 and the support plate 140, causing resistance to the flow of high-temperature and high-pressure gases, affecting the exhaust efficiency, and having poor safety.

[0081] See Figure 4 and Figure 7 In this embodiment, an installation hole 110 is provided in the middle of the cover plate body 100 along the first direction. The installation hole 110 can be formed by stamping or cutting. A limiting flange 111 is provided on the inner wall of the installation hole 110. The explosion-proof valve 400 can be inserted into the installation hole 110 from the side of the cover plate body 100 facing the plastic part 300 and abuts against the limiting flange 111 on the inner wall of the installation hole 110. At this time, it indicates that the explosion-proof valve 400 is installed in place, and the explosion-proof valve 400 and the cover plate body 100 can be welded. Through the setting of the limiting flange 111, the positioning between the explosion-proof valve 400 and the cover plate body 100 is ensured to be accurate, and the assembly accuracy is relatively high. In addition, the limiting flange 111 can also play a role in temporarily fixing the explosion-proof valve 400, facilitating the welding of the explosion-proof valve 400 and the cover plate body 100.

[0082] Optionally, the explosion-proof valve 400 includes a fixing part 410 and a body part 420. The fixing part 410 is disposed around the circumference of the body part 420. A scoring groove 421 is provided on the body part 420. The scoring groove 421 is in a C shape or a ring shape. The part surrounded by the scoring groove 421 forms an opening part 430. When the explosion-proof valve 400 is inserted into the installation hole 110 from the side of the cover plate body 100 facing the plastic part 300, the end face of the fixing part 410 facing the cover plate body 100 abuts against the limiting flange 111, and the circumferential side of the fixing part 410 is attached to the inner wall of the installation hole 110 and is welded. When the pressure in the battery accommodation cavity is too high, the scoring groove 421 on the body part 420 will be broken through, and a pressure relief channel is formed at the opening part 430. High-temperature and high-pressure gases can be discharged from the pressure relief channel outside the battery accommodation cavity, avoiding safety risks such as explosion.

[0083] Further, the total area of the explosion-proof valve 400 is S0, and the area of the opening part 430 is equal to the area of the pressure relief channel, that is, the area of the opening part 430 is also S2. The relationship between S0 and S2 satisfies: 0.80 ≤ S2 / S0 ≤ 0.90. For example, the value of S2 / S0 can be 0.80, 0.85, 0.90, etc. Thus, it is ensured that the flow area of the pressure relief channel is sufficient, and the high-temperature and high-pressure gas is discharged smoothly. At the same time, the mechanical strength of the fixing part 410 is sufficient, and the connection strength between the fixing part 410 and the cover body 100 is relatively high. Otherwise, when the value of S2 / S0 is too large, the area of the fixing part 410 is small, resulting in a low welding strength between the fixing part 410 and the cover body 100, insufficient connection strength between the explosion-proof valve 400 and the cover body 100, and the fixing part 410 is prone to deformation. Of course, the value of S2 / S0 should not be too small, otherwise the flow area of the pressure relief channel is insufficient, which may lead to untimely pressure relief and pose a safety risk.

[0084] Continue to refer to Figure 4 and Figure 7 , the outer circumference of the explosion-proof valve 400 includes two arc segments 411 and two straight segments 412. The two straight segments 412 are arranged oppositely along the first direction, the two arc segments 411 are arranged oppositely along the second direction, and the two arc segments 411 can form a complete circle. Since the fixing part 410 is located at the outermost side of the explosion-proof valve 400, that is, the outer circumference of the fixing part 410 includes the above two arc segments 411 and two straight segments 412.

[0085] Thus, the calculation formula for S0 can be obtained as:

[0086]

[0087] The total area of the explosion-proof valve 400 can be obtained through the above formula.

[0088] Among them, the distance between the two straight segments 412 along the first direction is W1, and the distance between the mutually departing endpoints of the two arc segments 411 along the second direction is L1. Since the outer circumference of the fixing part 410 fits with the inner wall of the mounting hole 110, the dimension of the mounting hole 110 along the first direction is also W1, and the dimension of the mounting hole 110 along the second direction is L1. Exemplarily, the value range of W1 is: 15mm ≤ W1 ≤ 40mm. For example, the value of W1 can be 15mm, 20mm, 30mm, 40mm, etc. The value range of L1 is: 25mm ≤ L1 ≤ 65mm. For example, the value of L1 can be 25mm, 30mm, 40mm, 50mm, 60mm, etc.

[0089] The dimension of the cover plate body 100 in the second direction is C, and L1 < C. Thus, a partial installation space is reserved on the side of the cover plate body 100 in the width direction, facilitating the welding operation between the cover plate body 100 and the housing 200, and avoiding deformation or cracking of the explosion-proof valve 400 caused by the thermal influence during the welding of the cover plate body 100 and the housing 200, which affects the accuracy of the opening pressure of the explosion-proof valve 400.

[0090] Further, the length of the first support platform 120 in the second direction is L2, and the length of the second support platform 130 in the second direction is L3. The relationship among L1, L2, and L3 satisfies: L1 ≥ L2 > L3. Thus, it can be ensured that the high-temperature and high-pressure gas flowing along the length direction (the first direction) of the cover plate body 100 circulates smoothly, avoiding the first support platform 120 or the second support platform 130 from blocking the high-temperature and high-pressure gas flowing along the length direction of the cover plate body 100, resulting in a decrease in flow velocity and exhaust efficiency. The relationship between L2 and L3 also satisfies: 5 mm ≤ L2 - L3 ≤ 10 mm. For example, the value of L2 - L3 can be 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, or 10 mm, etc. The value range of L3 is: 20 mm ≤ L3 ≤ 60 mm.

[0091] In some embodiments, when the value of L1 is 25 mm, the value of L2 can be 25 mm, and the value of L3 can be 20 mm. In some embodiments, when the value of L1 is 30 mm, the value of L2 can be 30 mm, and the value of L3 can be 25 mm, 20 mm, etc. In some embodiments, when the value of L1 is 65 mm, the value of L2 can be 65 mm, and the value of L3 can be 60 mm, 55 mm, 50 mm, etc., which will not be listed one by one here.

[0092] It should be noted that the values of L2 and L3 should not be too large. Otherwise, the end of the first support platform 120 in the second direction is too close to the side of the cover plate body 100 in the second direction, and the end of the second support platform 130 in the second direction is too close to the side of the cover plate body 100 in the second direction. When the plastic part 300 is heat-melt fixed to the cover plate body 100, affected by the accuracy of the processing equipment, the risk of interference between the support plate 140 and the plastic part 300 is relatively large, and the assembly accuracy decreases. Of course, the values of L2 and L3 should not be too small either, otherwise the supporting effect of the first support platform 120 and the second support platform 130 on the support plate 140 is not good, and the risk of deformation of the support plate 140 after being stamped by the electrode group increases, which may affect exhaust and pose a safety risk.

[0093] Further, the width of the second support platform 130 in the first direction is W3, and the following relationship is satisfied among the width W2 of the first support platform 120 in the first direction, the width W3 of the second support platform 130 in the first direction, and the length B of the support plate 140 in the first direction: 2*W1 + 2*W2 < B, ensuring a relatively large flow area of the exhaust gap 1411. The value range of W3 is 5 mm ≤ W3 ≤ 10 mm. For example, the value of W3 can be 5 mm, 8 mm, 10 mm, etc.

[0094] By obtaining the specific values of the above S11, S12, S1, and S2. Then calculate whether the values of S1 / S2 and S12 / S1 satisfy the corresponding value ranges, and further determine whether the support structure can meet the exhaust requirements during battery thermal runaway.

[0095] Further, according to different reaction systems of the battery, the gas generation amount of the electrode group varies when the battery undergoes thermal runaway. For example, when the electrode group of the battery is a ternary lithium system, the reaction between the electrode group and the electrolyte is relatively intense, and the gas generation amount during battery thermal runaway is large. At this time, the value range of S1 / S2 is 3.0 ≤ S1 / S2 ≤ 4.0, and the value range of S12 / S1 is 0.35 ≤ S12 / S1 ≤ 0.50.

[0096] The following uses some samples with different design sizes to verify the thermal runaway of the above ternary lithium system battery, and determine whether the battery can successfully pass the safety test. Among them, the standard for passing the safety test is that the explosion-proof valve 400 of the battery can open smoothly, the opening pressure is accurate, and no explosion occurs. The results are shown in Table 1.

[0097] Table 1

[0098]

[0099] From the above results, it can be concluded that in Sample 1 and Sample 2, the values of S1 / S2 and S12 / S1 do not satisfy their corresponding value ranges, the total flow area of the exhaust passage is insufficient, and the sum of the flow areas of all exhaust holes is small. The flow of high-temperature and high-pressure gases is not smooth, there is a situation where the explosion-proof valve 400 cannot be opened in time, there is a safety risk, the passing rate of the battery safety test is low, and the battery is defective.

[0100] In Sample 3, the value of S1 / S2 does not satisfy its corresponding value range, the total flow area of the exhaust passage is insufficient, the flow of high-temperature and high-pressure gases is not smooth, there is a situation where the explosion-proof valve 400 cannot be opened in time, there is a safety risk, the passing rate of the battery safety test is low, and the battery is defective.

[0101] In Sample 4, the value of S12 / S1 does not meet its corresponding range of values. The total flow area of all exhaust holes is too small, and the electrode group blocks the mounting hole 110. The flow of high-temperature and high-pressure gas along the third direction is not smooth, and there is a situation where the explosion-proof valve 400 cannot be opened in time, presenting a safety risk. The passing rate of the battery's safety test is low, and the battery is defective.

[0102] In Sample 5, the value of S12 / S1 is too large, that is, the total flow area of all exhaust holes is relatively large. Although the explosion-proof valve 400 can be opened normally, the structural strength of the support plate 140 is weak, and there is bending deformation. The exhaust space between the support plate 140 and the cover body 100 is insufficient, resulting in the inability of the explosion-proof valve 400 to exhaust smoothly, presenting a safety risk. The passing rate of the battery's safety test is not high, and the battery is defective.

[0103] In Samples 6, 7, and 8, the values of S1 / S2 and S12 / S1 both meet their corresponding ranges of values. At this time, the support structure has an obvious supporting effect on the electrode group, and the total flow area of the exhaust passage is sufficient. The explosion-proof valve 400 can be opened smoothly and the explosion-proof valve 400 exhausts smoothly, with a relatively high exhaust efficiency. The safety tests of the batteries all pass, and no explosion occurs. The battery products are good.

[0104] When the electrode group of the battery is a lithium iron phosphate system, the reaction between the electrode group and the electrolyte is relatively slow, and the gas generation amount during battery thermal runaway is smaller than that of a ternary lithium system battery. At this time, the range of values of S1 / S2 is 2.0 ≤ S1 / S2 ≤ 3.0, and the range of values of S12 / S1 is 0.20 ≤ S4 / S3 ≤ 0.50.

[0105] The following uses some samples with different design dimensions to verify the thermal runaway of the above lithium iron phosphate system battery and determine whether the battery can pass the safety test smoothly. Among them, the standard for passing the safety test is that the explosion-proof valve 400 of the battery can be opened smoothly, the opening pressure is accurate, and no explosion occurs. The results are shown in Table 2.

[0106] Table 2

[0107]

[0108] From the above results, it can be concluded that in Sample 1, the values of S1 / S2 and S12 / S1 do not meet their corresponding ranges of values. The total flow area of the exhaust passage is insufficient, and the total flow area of all exhaust holes is too small. The flow of high-temperature and high-pressure gas is not smooth, and there is a situation where the explosion-proof valve 400 cannot be opened in time, presenting a safety risk. The passing rate of the battery's safety test is low, and the battery is defective.

[0109] In sample 2, the value of S12 / S1 does not satisfy its corresponding value range, the sum of the flow areas of all exhaust holes is too small, the pole group blocks the mounting hole 110, the flow of high-temperature and high-pressure gas is not smooth, and the explosion-proof valve 400 cannot be opened in time, posing a safety risk, the battery safety test pass rate is low, and the battery is defective.

[0110] In sample 3, the value of S12 / S1 is too large, that is, the sum of the flow areas of all exhaust holes is large. Although the explosion-proof valve 400 can be opened normally, the structural strength of the support plate 140 is weak and there is bending deformation. The exhaust space between the support plate 140 and the cover body 100 is insufficient, resulting in the explosion-proof valve 400 being unable to exhaust smoothly, posing a safety risk. The battery safety test pass rate is not high, and the battery is defective.

[0111] In samples 4, 5, 6 and 7, the values of S1 / S2 and S12 / S1 all satisfy their corresponding value ranges. At this time, the supporting effect of the supporting structure on the electrode group is obvious, and the total flow area of the exhaust channel is sufficient. The explosion-proof valve 400 can open the valve smoothly and the explosion-proof valve 400 exhausts smoothly, the exhaust efficiency is high, the battery safety tests are passed, no explosion occurs, and the battery product is good.

[0112] In summary, it can be seen that the size design and position arrangement of the support structure have a great influence on the supporting effect of the electrode group and the exhaust effect of the explosion-proof valve 400. After the type of battery is selected, the size design of the support structure specified by the corresponding battery type can ensure that the supporting structure has a good supporting effect on the electrode group, and at the same time, the exhaust of the explosion-proof valve 400 is not affected, which significantly improves the problem of the explosion-proof valve 400 being blocked by the electrode group and affecting the exhaust when the battery is thermally runaway, and the battery has high safety performance.

[0113] Embodiment 2

[0114] This embodiment further provides a battery, which is different from the battery in the first embodiment in that the mounting hole 110 and the supporting structure in this embodiment are arranged on one of the side walls of the housing 200 .

[0115] See also Figure 8 The battery in this embodiment may be a blade battery, and the housing 200 is arranged along the first direction ( Figure 8 Openings 201 are formed at both ends of the cover body 100 (in the X-axis direction shown in the figure), and two cover bodies 100 are provided. Each cover body 100 is connected to an opening 201 of the shell 200 and blocks the opening 201. The two cover bodies 100 and the shell 200 form a receiving cavity for placing the pole group.

[0116] The housing 200 includes a Figure 8 The X-axis direction and the Y-axis direction shown in the figure are both perpendicular) are oppositely arranged two first side walls 210, and the second side walls 210 are arranged along the second direction (Figure 8 The first side wall 210 is connected to the second side wall 220, and the area of the first side wall 210 is smaller than the area of the second side wall 220. In this embodiment, the mounting hole 110 and the support structure are arranged on the first side wall 210 as an example for description, and the plastic part 300 is arranged on a side of the first side wall 210 close to the accommodating cavity, and the plastic part 300 abuts against a side of the support structure away from the first side wall 210.

[0117] Specifically, the support structure is arranged on the side of the first side wall 210 of the shell 200 close to the plastic part 300, and an exhaust space is formed between the support plate 140 and the first side wall 210 of the shell 200. An exhaust gap 1411 is formed between the first side surface 1401 of the support plate 140 facing the cover body 100 and the end surface of the first side wall 210 facing the support plate 140. The exhaust gap 1411 and the exhaust hole on the support plate 140 connect the accommodating cavity with the exhaust space. Through the above arrangement, after the battery has thermal runaway and the plastic part 300 is melted, the support structure arranged on the shell 200 can continue to support the pole group, and the high-temperature and high-pressure gas can enter the exhaust space from the exhaust gap 1411 or the exhaust hole, and then flow to the pressure relief channel of the explosion-proof valve 400 for directional discharge, so as to achieve rapid pressure relief, and the safety of the battery is good.

[0118] Furthermore, the sum of the flow areas of all exhaust gaps 1411 is S11, and the sum of the flow areas of all exhaust holes is S12. The total flow area of all exhaust gaps 1411 and all exhaust holes can be recorded as S1, which is also the total flow area of the exhaust channel. S1, the flow area of the pressure relief channel is S2, and S1 and S2 satisfy: 2.0≤S1 / S2≤4.0. For example, in some embodiments, the value of S1 / S2 can be 2.0, 2.5, 3.0, 3.5 or 4.0, etc. In this way, the total flow area of the exhaust channel is guaranteed to match the flow area of the pressure relief channel of the explosion-proof valve 400, meet the circulation needs of high-temperature and high-pressure gas, avoid explosion caused by excessive pressure in the accommodating chamber, and have higher safety. At the same time, the mechanical strength of the supporting structure is higher and deformation problems are not easy to occur. The value range of S2 is: 260mm 2 ≤S2≤1100mm 2 For example, the value of S2 can be 260mm 2 、300mm 2 , 500mm 2 , 800mm 2 or 1100mm 2 Etc. Accordingly, the value of S1 can be calculated according to the above value range of S1 / S2.

[0119] The rest of the structure of the battery in this embodiment is the same as that in the first embodiment and will not be described again here.

[0120] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, rather than limitations on the implementation manners of the present invention. For those of ordinary skill 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 enumerate all the implementation manners here. Any modifications, equivalent substitutions, and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the claims of the present invention.

Claims

1. A battery, characterized in that, include: A cover body and a shell, wherein the cover body is connected to the shell and encloses a receiving cavity, and at least one of the cover body and the shell is provided with a mounting hole and a supporting structure, wherein the mounting hole is used to mount an explosion-proof valve, and a pressure relief channel is formed when the explosion-proof valve is opened; The support structure includes two first support platforms and a support plate, the two first support platforms are arranged on both sides of the mounting hole along the first direction, the two ends of the support plate along the first direction are respectively connected to one of the first support platforms, an exhaust space is formed between the support plate and the cover plate body or the shell, and the exhaust space is communicated with the pressure relief channel; The support plate has two first side surfaces that are arranged opposite to each other along the second direction, and a gas exhaust gap is formed between a side of each of the first side surfaces that faces the cover plate body or the shell and an end surface of the cover plate body or the shell that faces the support plate, and the gas exhaust gap connects the accommodating cavity with the gas exhaust space; a plurality of gas exhaust holes are provided on the support plate, and the plurality of gas exhaust holes penetrate the support plate along the third direction, and the gas exhaust holes connect the accommodating cavity with the gas exhaust space; The sum of the flow areas of all the exhaust gaps is S11, the sum of the flow areas of all the exhaust holes is S12, S1=S11+S12; the flow area of the pressure relief channel is S2; S1 and S2 satisfy: 2.0≤S1 / S2≤4.0; The value range of S2 is: 260 mm 2 ≤ S2 ≤ 1100 mm 2 .

2. The battery according to claim 1, wherein The relationship between the sum of the flow areas of all the exhaust gaps S11 and the sum of the flow areas of all the exhaust holes S12 satisfies: 0.25≤S12 / S1≤0.50; The value range of S12 is: 400mm 2 ≤ S12 ≤ 1600mm 2 .

3. The battery according to claim 1, characterized in that, The battery further comprises a plastic part, which is arranged on a side of the cover body or the shell close to the accommodating cavity, and the plastic part abuts against an end surface of the support plate facing away from the cover body or the shell.

4. The battery according to claim 1, wherein Some of the multiple exhaust holes are first exhaust holes, and the projection of the first exhaust holes on the cover body or the shell along the third direction at least partially overlaps with the explosion-proof valve, and the remaining exhaust holes are second exhaust holes, which are arranged in an array on the support plate.

5. The battery according to claim 4, wherein, The second exhaust hole is a square hole, the side length of the square hole is a1, and the value range of a1 is 3mm≤a1≤10mm.

6. The battery according to claim 1, wherein The two first support platforms spaced apart in the first direction have their sides facing away from each other flush with one end of the support plate in the first direction, and the two sides of the support plate facing away from each other in the second direction flush with one end of the first support platform in the second direction; The length of the support plate along the first direction is B, the width of the first support platform along the first direction is W2; the height of the first support platform along the third direction is H; The calculation formula of S11 is: S11 = 2*(B-2*W2)*H; The value range of B is 100mm≤B≤180mm; The value range of W2 is 5mm≤W2≤10mm; The value range of H is 1.5mm≤H≤3.0mm.

7. The battery according to claim 1, wherein The support structure further includes two second support platforms, each of the second support platforms being clamped between one of the first support platforms and the mounting hole, and one side of the second support platform facing away from the cover body or the housing is connected to the support plate.

8. The battery according to claim 7, characterized in that, The contact area between each of the first support platforms and the support plate is S31, the contact area between each of the second support platforms and the support plate is S32, and the total contact area between the support plate and the first support platforms and the second support platforms is S3; The calculation formula for S3 is: S3 = 2 * S31 + 2 * S32; The value range of S3 is 700 mm 2 ≤S3≤2500 mm 2 .

9. The battery according to claim 1, characterized in that, The explosion-proof valve includes a fixing portion and a body portion. The fixing portion is disposed around the circumference of the body portion. A scoring groove is provided on the body portion, and the portion surrounded by the scoring groove forms an opening portion. The circumferential side of the fixing portion is in close contact with the inner wall of the mounting hole and is connected by welding. The area of the opening portion is equal to the area of the pressure relief passage; The total area of the explosion-proof valve is S0, and S0 and S2 satisfy: 0.80 ≤ S2 / S0 ≤ 0.

90.

10. The battery according to claim 9, characterized in that, The outer circumference of the explosion-proof valve includes two arc segments and two straight segments. The two straight segments are disposed opposite to each other in the first direction, and the two arc segments are disposed opposite to each other in the second direction, and the two arc segments can form a complete circle; The calculation formula for S0 is: wherein, the distance between the two straight segments in the first direction is W1, and the distance between the mutually departing end points of the two arc segments in the second direction is L1; The value range of W1 is: 15 mm ≤ W1 ≤ 40 mm; The value range of L1 is: 25 mm ≤ L1 ≤ 65 mm.

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