Battery

Abstract

The invention relates to the technical field of batteries, and particularly discloses a battery which comprises an anti-explosion valve, a cover plate body, a shell and a plastic part, at least one of the cover plate body and the shell is provided with a mounting hole and a supporting structure, the anti-explosion valve is arranged in the mounting hole, and the supporting structure comprises a plurality of supporting tables arranged in the circumferential direction of the mounting hole; the supporting tables and the mounting holes are arranged at intervals, and an exhaust channel is formed between every two adjacent supporting tables. The plastic part is arranged on the side, close to the containing cavity, of the cover plate body or the shell, the end, away from the cover plate body or the shell, of the supporting table abuts against the plastic part, and the cover plate body or the shell is insulated from the pole set through the plastic part. After the battery is subjected to thermal runaway and a plastic part is melted, the plurality of supporting tables arranged on the cover plate body or the shell can continuously support the pole group, so that the pole group is prevented from shielding a mounting hole in the cover plate body or the shell, smooth exhaust of the explosion-proof valve is ensured, rapid pressure relief can be realized, and the safety of the battery is good.

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, ensuring 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 generally melts 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] The present invention provides a battery, including:

[0007] An explosion-proof valve;

[0008] A cover body and a housing, the cover body is connected to the housing and encloses to form a receiving cavity, at least one of the cover body and the housing is provided with an installation hole and a support structure, the installation hole is used for installing the explosion-proof valve, the support structure includes a plurality of support platforms, the plurality of support platforms are all arranged on the circumference of the installation hole, and each support platform is spaced from the installation hole, and an exhaust passage is formed between two adjacent support platforms;

[0009] A plastic part is arranged on a side of the cover body or the shell close to the accommodating cavity, and an end of the support platform away from the cover body or the shell abuts against the plastic part;

[0010] The perimeter of the mounting hole is S1, the sum of the lengths of all the support platforms is S2, and S1 and S2 satisfy: 0.65≤S2 / S1≤1.1.

[0011] Optionally, the mounting hole and the supporting structure are arranged on the cover body, the length of each supporting platform is S21, the number of the supporting platforms is n, and S2 and S21 satisfy: S2=S21·n;

[0012] Among them, the value range of S21 is: 10mm≤S21≤16mm.

[0013] Optionally, the width of the support platform is W, and the value range of W is: 5mm≤W≤8mm.

[0014] Optionally, along the width direction of the cover body, the distance between the side of the support platform away from the mounting hole and the adjacent side edge of the cover body is A, and the size of the cover body is F;

[0015] A and F satisfy: 0.12≤A / F≤0.2;

[0016] The value range of A is: 5mm≤A≤10mm;

[0017] The value range of F is: 25mm≤F≤75mm.

[0018] Optionally, a distance between a side of the support platform close to the mounting hole and an adjacent side of the mounting hole is D, and a value range of D is: 4mm≤D≤6mm.

[0019] Optionally, along a direction perpendicular to an end face of the cover body or the shell, a height of the support platform is H, and a value range of H is 3 mm ≤ H ≤ 5 mm.

[0020] Optionally, when the battery is a ternary lithium system, S1 and S2 satisfy: 0.85≤S2 / S1≤1.1;

[0021] When the battery is a lithium iron phosphate system, S1 and S2 satisfy the following relationship: 0.65≤S2 / S1≤0.8.

[0022] Optionally, the plastic part is provided with a plurality of ventilation holes, which are arranged at intervals on the plastic part, and along a direction perpendicular to the end face of the cover body or the shell, the projections of the plurality of ventilation holes on the cover body or the shell at least partially overlap with the projections of the mounting holes on the cover body or the shell.

[0023] Optionally, a side of the plastic part facing the cover body or the shell is provided with an avoidance groove, and the support platform is embedded in the avoidance groove.

[0024] The beneficial effects of the present invention are:

[0025] The present invention provides a battery, comprising an explosion-proof valve, a cover body, a shell and a plastic part, wherein the cover body is connected to the shell and forms a housing cavity for placing a pole group together with the shell. At least one of the cover body and the shell is provided with a mounting hole and a support structure, the explosion-proof valve is arranged in the mounting hole, the support structure comprises a plurality of support platforms, the plurality of support platforms are all arranged in the circumference of the mounting hole, each support platform is arranged at intervals from the mounting hole, and two adjacent support platforms are also arranged at intervals to form an exhaust channel between the two adjacent support platforms. The plastic part is arranged on one side of the cover body or the shell close to the housing cavity, the end of the support platform facing away from the cover body or the shell abuts against the plastic part, and the cover body is insulated from the pole group by the plastic part.

[0026] Through the above arrangement, after the battery has thermal runaway and the plastic parts are melted, the multiple support platforms arranged on the cover body or the shell can continue to support the electrode group, so as to prevent the electrode group from randomly flowing with the high-temperature and high-pressure gas, resulting in the mounting holes on the cover body being blocked by the electrode group. The high-temperature and high-pressure gas can pass through the exhaust channel between two adjacent support platforms on the cover body, and then flow to the mounting hole and be discharged directionally through the explosion-proof valve arranged in the mounting hole. The flow path of the high-temperature and high-pressure gas is smooth and the flow speed is fast. The exhaust effect of the explosion-proof valve is good, which can achieve rapid pressure relief and the safety of the battery is good. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the contents of the embodiments of the present invention and these drawings without paying any creative work.

[0028] Figure 1 This is a schematic structural diagram of the cover plate body provided in the first embodiment of the present invention;

[0029] Figure 2 for Figure 1 A partial enlarged view of the middle A;

[0030] Figure 3 This is the top view of the cover body provided in the first embodiment of the present invention;

[0031] Figure 4 This is the structural schematic diagram of the battery provided in the second embodiment of the present invention;

[0032] Figure 5 This is the partial enlarged view of the battery provided in the second embodiment of the present invention.

[0033] In the figure:

[0034] 100, cover body; 110, mounting hole; 111, limiting flange; 120, support platform; 120a, first boss; 120b, second boss; 121, exhaust passage; 200, housing; 210, first side wall; 220, second side wall. Detailed implementation manners

[0035] Next, the technical solutions of the present invention will be clearly and completely described in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. 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.

[0036] 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 accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be understood 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, and moreover, the first feature being "above", "above" and "on" the second feature includes the first feature being directly above and obliquely above the second feature, or simply indicating that the first feature has a higher horizontal height than the second feature. The first feature being "below", "below" and "under" the second feature includes the first feature being directly below and obliquely below the second feature, or simply indicating that the first feature has a lower horizontal height than the second feature.

[0037] In the description of the present invention, it should be noted that, unless otherwise clearly defined and limited, the terms "installation", "connection", and "coupling" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components. 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.

[0038] The embodiments of the present invention will be described in detail below. The examples of the embodiments are shown in the drawings, where the same or similar reference numerals represent the same or similar elements or elements with 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 to the present invention.

[0039] Embodiment 1

[0040] As Figures 1-3 shown, this embodiment provides a battery, which includes an explosion-proof valve, a cover body 100, a housing 200, and a plastic part. The cover body 100 is connected to the housing 200 and together with the housing 200 forms a receiving cavity for placing the electrode group. The cover body 100 is provided with an installation hole 110 and a support structure. The explosion-proof valve is arranged in the installation hole 110. The support structure includes a plurality of support platforms 120, and the plurality of support platforms 120 are all arranged on the circumference of the installation hole 110. The installation hole 110 in this embodiment is in a runway shape, and the plurality of support platforms 120 enclose a quasi-annular structure. The quasi-annular structure has the same shape as the installation hole 110 and is concentric with the installation hole 110. Each support platform 120 is arranged at an interval from the installation hole 110, and adjacent two support platforms 120 are also arranged at an interval to form an exhaust channel 121 between adjacent two support platforms 120. The plastic part is arranged on the side of the cover body 100 close to the receiving cavity. The end of the support platform 120 facing away from the cover body 100 abuts against the plastic part, and the cover body 100 is insulated from the electrode group through the plastic part.

[0041] Through the above settings, when the battery undergoes thermal runaway and the plastic part is melted, the plurality of support platforms 120 arranged on the cover body 100 can continue to support the electrode group, preventing the electrode group from randomly flowing with the high-temperature and high-pressure gas, resulting in the installation hole 110 on the cover body 100 being blocked by the electrode group. The high-temperature and high-pressure gas can pass through the exhaust channel 121 between adjacent two support platforms 120 on the cover body 100, and then flow to the installation hole 110 and be discharged directionally through the explosion-proof valve arranged in the installation hole 110. The flow path of the high-temperature and high-pressure gas is smooth, the flow speed is fast, the exhaust effect of the explosion-proof valve is good, rapid pressure relief can be achieved, and the safety of the battery is good. It should be noted that at this time, the explosion-proof valve is in an open valve state.

[0042] Furthermore, the perimeter of the mounting hole 110 is S1, and the sum of the lengths of all the supporting platforms 120 is S2. The relationship between S1 and S2 satisfies: 0.65 ≤ S2 / S1 ≤ 1.1. For example, the value of S2 / S1 can be 0.65, 0.75, 0.80, 0.85, 0.90, or 1.1. By controlling the value of S2 / S1 within the above range, it can be ensured that the exhaust passage 121 formed between two adjacent supporting platforms 120 is relatively large. When the battery undergoes thermal runaway and the plastic part melts and fails, it can meet the circulation requirements of high-temperature and high-pressure gases. At the same time, the contact area between the supporting platform 120 and the electrode group is relatively large, which can provide good support for the electrode group to maintain the formation of the exhaust passage 121, and prevent the electrode group from moving towards the cover body 100 under the impact of high-temperature and high-pressure gases, resulting in the occlusion of the mounting hole 110 on the cover body 100. The exhaust efficiency of the explosion-proof valve is high, greatly improving the safety performance of the battery.

[0043] Continue to refer to Figure 3 , in this embodiment, some of the supporting platforms 120 extend along the length direction of the cover body 100, and some of the supporting platforms 120 extend along the width direction of the cover body 100. For the convenience of description, the supporting platform 120 extending along the length direction of the cover body 100 is denoted as the first convex platform 120a, and the supporting platform 120 extending along the width direction of the cover body 100 is denoted as the second convex platform 120b. The length direction of the cover body 100 is Figure 3 the X-axis direction shown in Figure 3 , denoted as the first direction here, and the width direction of the cover body 100 is

[0044] In this embodiment, it is exemplified that there are two first bosses 120a and six second bosses 120b. The two first bosses 120a are symmetrically arranged on the opposite sides of the mounting hole 110 along the second direction. The six second bosses 120b are divided into two groups, and the two groups of second bosses 120b are symmetrically arranged on the opposite sides of the mounting hole 110 along the first direction. Each group of second bosses 120b has three, and the three second bosses 120b are arranged at intervals along the second direction. The first boss 120a and the second boss 120b are also arranged at intervals. Thus, an exhaust passage 121 for the high-temperature and high-pressure gas to flow through is formed between the first boss 120a and the second boss 120b, and between two adjacent second bosses 120b. Furthermore, when the high-temperature and high-pressure gas flows along the first direction, the resistance is small, and it can be discharged to the mounting hole 110, ensuring that the explosion-proof valve opens smoothly and the exhaust is relatively smooth. Here, between S2 and S21, it satisfies: S2 = S21·8.

[0045] Furthermore, the width of the support platform 120 is W, that is, the dimension of the first boss 120a along the second direction is W, and the dimension of the second boss 120b along the first direction is W. The dimension of the first boss 120a along the second direction is equal to the dimension of the second boss 120b along the first direction. The value range of W is: 5mm ≤ W ≤ 8mm. For example, the value of W can be 5mm, 6mm, 7mm, 8mm, etc. By restricting the value of W within the above range, the contact area between each support platform 120 (including the first boss 120a and the second boss 120b) and the electrode group is relatively large, ensuring a good support effect of the support platform 120 on the electrode group, and the support platform 120 is not too sharp and is easy to be stamped. Otherwise, when the value of W is too small, the support effect of the support platform 120 on the electrode group decreases, there is a risk that the electrode group blocks the mounting hole 110 on the cover body 100, the exhaust of the explosion-proof valve is not smooth, and the support platform 120 is not easy to be stamped on the cover body 100, resulting in a low processing yield.

[0046] Furthermore, the multiple support platforms 120 are formed on the cover body 100 by stamping. The distance between the side of the support platform 120 close to the mounting hole 110 and the adjacent side of the mounting hole 110 is D, and the value range of D is: 4mm ≤ D ≤ 6mm. Specifically, along the second direction, the distance between the side of the first boss 120a close to the mounting hole 110 and the mounting hole 110 is D. Along the first direction, the distance between the side of the second boss 120b close to the mounting hole 110 and the mounting hole 110 is also D. The distance between the first boss 120a and the mounting hole 110 is equal to the distance between the second boss 120b and the mounting hole 110.

[0047] Exemplarily, the value of D can be 4 mm, 5 mm, 6 mm, etc. By controlling the value of D within the above range, it can be ensured that after stamping and forming, the flatness of the positions around the mounting hole 110 on the cover plate body 100 is good, the assembly accuracy between the explosion-proof valve and the cover plate body 100 is high, the reliability of the explosion-proof valve is high, and it is not easy to fail. Otherwise, when the value of D is too small, the distance between the support platform 120 and the mounting hole 110 is too close, and the flatness of the positions around the mounting hole 110 on the cover plate body 100 is poor, affecting the welding quality between the explosion-proof valve and the cover plate body 100, and there is a risk of seal failure. Of course, the value of D should not be too large either, otherwise the distance between the support platform 120 and the mounting hole 110 is too far, the supporting effect on the electrode group decreases, and there is a risk of the electrode group blocking the mounting hole 110 on the cover plate body 100.

[0048] Optionally, a limiting flange 111 is provided on the inner wall of the mounting hole 110. The explosion-proof valve can be inserted into the mounting hole 110 from one side of the cover plate body 100 and abutted against the limiting flange 111 on the inner wall of the mounting hole 110. At this time, it indicates that the explosion-proof valve is installed in place, and the explosion-proof valve can be welded to the cover plate body 100. Through the setting of the limiting flange 111, the positioning between the explosion-proof valve 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, facilitating the welding operation between the explosion-proof valve and the cover plate body 100.

[0049] Continue to refer to Figure 3 , along the width direction of the cover plate body 100, in this embodiment, the distance between the side of the first boss 120a facing away from the mounting hole 110 and the adjacent side of the cover plate body 100 is A, and the size of the cover plate body 100 is F. The relationship between A and F satisfies: 0.12 ≤ A / F ≤ 0.2. For example, the value of A / F can be 0.12, 0.14, 0.16, 0.18, or 0.20, etc. Among them, the value range of A is: 5 mm ≤ A ≤ 10 mm, and the value range of F is: 25 mm ≤ F ≤ 75 mm. That is, when the value of A is 5 mm, the value of F can be 25 mm, 30 mm, 35 mm, 40 mm, or 42 mm, etc. When the value of A is 10 mm, the value of F can be 50 mm, 60 mm, 70 mm, or 80 mm, etc. Among them, the value range of A is: 5 mm ≤ A ≤ 10 mm, and the value range of F is: 25 mm ≤ F ≤ 75 mm. That is, when the value of A is 5 mm, the value of F can be 25 mm, 30 mm, 35 mm, 40 mm, or 42 mm, etc. When the value of A is 10 mm, the value of F can be 50 mm, 60 mm, 70 mm, or 75 mm, etc.

[0050] By restricting the value of A / F within the above range, a certain space is ensured between the first boss 120a and the side of the cover body 100 along the second direction, facilitating the assembly of the cover body 100 and the housing 200. At the same time, it also makes the resistance of the high-temperature and high-pressure gas flowing along the first direction relatively small, ensuring the smooth opening of the explosion-proof valve and relatively smooth exhaust. It should be noted that the value of A / F should not be too small, otherwise the high-temperature and high-pressure gas will be blocked when flowing along the first direction, and there is a situation where the explosion-proof valve fails to open in time, posing a safety risk; the value of A / F should not be too large either, otherwise the distance between the first boss 120a and the mounting hole 110 is relatively small, the supporting effect on the electrode group is not good, and there is a risk that the mounting hole 110 on the cover body 100 is blocked by the electrode group, resulting in poor exhaust of the explosion-proof valve.

[0051] Continue to refer to Figure 2 , in the direction perpendicular to the end face of the cover body 100 (i.e., Figure 1 the Z-axis direction shown in

[0052] , denoted as the third direction here), the height of the support platform 120 is H, and the value range of H is 3mm ≤ H ≤ 5mm. For example, the value of H can be 3mm, 4mm, 5mm, etc. By restricting the value of H within the above range, the flow area of the exhaust channel 121 formed between two adjacent support platforms 120 is relatively large. Furthermore, when the plastic part is melted and the support platform 120 abuts against the electrode group, the exhaust space between the cover body 100 and the electrode group is relatively large, which is beneficial to improving the exhaust efficiency of the explosion-proof valve and has high safety.

[0053] Furthermore, a plurality of ventilation holes are provided on the plastic part, and the plurality of ventilation holes are arranged at intervals on the plastic part. In the direction perpendicular to the end face of the cover body 100 (i.e., the third direction), at least part of the projection of the plurality of ventilation holes on the cover body 100 coincides with the projection of the mounting hole 110 on the cover body 100. After the battery undergoes thermal runaway and the internal temperature of the battery has not risen to the melting point of the plastic part, the plastic part maintains its pre-melted form to support the electrode group. At this time, the high-temperature and high-pressure gas in the accommodation cavity can be discharged to the explosion-proof valve through the ventilation holes, so that the explosion-proof valve opens and relieves pressure. A relief groove is provided on the side of the plastic part facing the cover body 100, and the support platform 120 is embedded in the relief groove. Through the setting of the relief groove, the waste of space in the accommodation cavity can be avoided, the occupied space of the cover body 100 can be reduced, which is beneficial to increasing the volume of the electrode group and improving the energy density of the battery.

[0053] When the battery is a ternary lithium system, the relevant parameters S1 and S2 of the cover body 100 of the battery satisfy: 0.85 ≤ S2 / S1 ≤ 1.1.

[0054] Next, some samples with different design dimensions are used to verify the thermal runaway of the ternary lithium system battery with the above structure. The capacity of the battery is 350Ah and the voltage is 3.5V. The verification results are shown in Table 1.

[0055] Table 1

[0056]

[0057] From the above results, it can be concluded that in Sample 1 and Sample 2, the value of D is less than the minimum value of 4mm≤D≤6mm, the value of W satisfies its corresponding value range, and S1 and S2 satisfy: 0.85≤S2 / S1≤1.1. At this time, the distance between the support platform 120 and the mounting hole 110 is too close, and the support platform 120 has a poor supporting effect on the electrode group, and the designed gap cannot be maintained between the cover body 100 and the electrode group. The explosion-proof valve is not vented smoothly, the pass rate of the battery thermal runaway test is low, and the battery product is defective.

[0058] In samples 3 and 4, the value of W is less than the minimum value of 5mm≤W≤8mm, and the values ​​of D and S2 / S1 satisfy their corresponding value ranges. At this time, the width of the support platform 120 along the direction perpendicular to its extension is small, and the contact area with the electrode group is small. The supporting effect of the electrode group is not obvious, and the exhaust space between the cover body 100 and the electrode group is small, which cannot ensure smooth exhaust of the explosion-proof valve. The pass rate of the battery thermal runaway test is low, and there is a risk of explosion, which makes the battery product defective.

[0059] In samples 5 and 6, the values ​​of D, W, and S2 / S1 all satisfy their corresponding value ranges. At this time, the support platform 120 has an obvious supporting effect on the electrode group, the exhaust space formed between the cover body 100 and the electrode group is large, the explosion-proof valve exhausts smoothly, the exhaust efficiency is high, the battery thermal runaway test is passed, no explosion occurs, and the battery product is good.

[0060] In samples 7 and 8, the value of S2 / S1 is less than the minimum value of 0.85≤S2 / S1≤1.1, and the values ​​of D and W satisfy their corresponding value ranges. At this time, the exhaust channel 121 formed between the two adjacent support platforms 120 is small, and the exhaust space formed between the cover body 100 and the pole group is small. It is impossible to ensure that the explosion-proof valve is exhausted in time, and there is a certain risk of explosion. The pass rate of the battery thermal runaway test is low, and the battery product is defective.

[0061] When the battery is a lithium iron phosphate system, the relevant parameters S1 and S2 of the battery cover body 100 satisfy the following relationship: S1 and S2 satisfy the following relationship: 0.65≤S2 / S1≤0.8.

[0062] The thermal runaway of the lithium iron phosphate battery of the above structure is verified by using some samples of different design sizes. The capacity of the battery is 350Ah and the voltage is 3.5V. The verification results are shown in Table 2.

[0063] Table 2

[0064]

[0065] From the above results, it can be concluded that in Sample 1 and Sample 2, the value of D is less than the minimum value of 4 mm ≤ D ≤ 6 mm, the value of W satisfies its corresponding value range, and between S1 and S2: 0.65 ≤ S2 / S1 ≤ 0.8. At this time, the distance between the support platform 120 and the mounting hole 110 is too close, the support effect of the support platform 120 on the pole group is not good, the designed gap between the cover body 100 and the pole group cannot be maintained, the explosion-proof valve has poor exhaust, the passing rate of the battery thermal runaway test is low, and the battery product is defective.

[0066] In Sample 3 and Sample 4, the value of W is less than the minimum value of 5 mm ≤ W ≤ 8 mm, and the values of D and S2 / S1 satisfy their corresponding value ranges. At this time, the width of the support platform 120 along the direction perpendicular to its extension is small, the contact area with the pole group is small, the support effect on the pole group is not obvious, the exhaust space between the cover body 100 and the pole group is small, the smooth exhaust of the explosion-proof valve cannot be guaranteed, the passing rate of the battery thermal runaway test is low, and there is an easy risk of explosion, and the battery product is defective.

[0067] In Sample 5 and Sample 6, the values of D, W, and S2 / S1 all satisfy their corresponding value ranges. At this time, the support effect of the support platform 120 on the pole group is obvious, the exhaust space formed between the cover body 100 and the pole group is large, the explosion-proof valve exhausts smoothly, the exhaust efficiency is high, all the battery thermal runaway tests pass, no explosion occurs, and the battery product is good.

[0068] In Sample 7 and Sample 8, the value of S2 / S1 is less than the minimum value of 0.65 ≤ S2 / S1 ≤ 0.8, and the values of D and W satisfy their corresponding value ranges. At this time, the exhaust channel 121 formed between two adjacent support platforms 120 is small, the exhaust space formed between the cover body 100 and the pole group is small, the timely exhaust of the explosion-proof valve cannot be guaranteed, there is a certain risk of explosion, the passing rate of the battery thermal runaway test is low, and the battery product is defective.

[0069] In summary, it can be seen that the size design and position arrangement of the support platform 120 have a great influence on the support effect of the pole group and the exhaust effect of the explosion-proof valve. When the size design defined in this embodiment is adopted, it can ensure that the support platform 120 has a good support effect on the pole group, and at the same time, the exhaust of the explosion-proof valve is not affected, significantly improving the problem that the explosion-proof valve is blocked by the pole group during battery thermal runaway and affecting exhaust, and the safety performance of the battery is high.

[0070] Embodiment 2

[0071] This embodiment also provides a battery, which is different from the battery in Embodiment 1 in that: the mounting hole 110 and the support structure in this embodiment are arranged on one side wall of the housing 200.

[0072] See Figure 4 and Figure 5The battery in this embodiment may be a blade battery, and the housing 200 is arranged along the first direction ( Figure 4 The two ends of the cover plate body 100 are formed with openings, and each cover plate body 100 is connected to an opening of the shell 200 and blocks the opening. The two cover plate bodies 100 and the shell 200 form a receiving cavity for placing the pole group. The shell 200 includes two first side walls 210 arranged opposite to each other along the third direction, and a first side wall 210 arranged along the second direction ( Figure 4 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. Figure 4 The X-axis direction and the Y-axis direction shown in the figure are both perpendicular. In this embodiment, the mounting hole 110 and the supporting structure are arranged on the first side wall 210 for illustration.

[0073] Specifically, the support structure includes a plurality of support platforms 120, which are arranged in the circumference of the mounting hole 110, and are spaced apart from the mounting hole 110. Two adjacent support platforms 120 are also spaced apart to form an exhaust channel 121 between the two adjacent support platforms 120. The plastic part is arranged on the side of the first side wall 210 close to the accommodating cavity, and the side of the support platform 120 away from the first side wall 210 along the third direction abuts against the plastic part, and the pole group is insulated from the housing 200 by the plastic part.

[0074] Further, the perimeter of the mounting hole 110 in this embodiment is S1, and the sum of the lengths of all the support platforms 120 is S2, and S1 and S2 satisfy: 0.65≤S2 / S1≤1.1. For example, the value of S2 / S1 can be 0.65, 0.75, 0.80, 0.85, 0.90 or 1.1. By controlling the value of S2 / S1 within the above range, the exhaust channel 121 formed between two adjacent support platforms 120 is larger, and when the battery has thermal runaway and the plastic part fails to melt, the circulation needs of high-temperature and high-pressure gas are met. At the same time, the contact area between the support platform 120 and the electrode group is large, which has a good supporting effect on the electrode group to maintain the existence of the exhaust channel 121, and prevent the electrode group from moving toward the first side wall 210 of the shell 200 under the impact of high-temperature and high-pressure gas, resulting in the mounting hole 110 on the first side wall 210 being blocked, the exhaust efficiency of the explosion-proof valve is high, and the safety performance of the battery is good.

[0075] Optionally, a plurality of vent holes are provided on the plastic part, and the plurality of vent holes are arranged at intervals on the plastic part. Along the third direction, the projection of the plurality of vent holes on the first side wall 210 of the housing 200 coincides at least partially with the projection of the mounting hole 110 on the first side wall 210 of the housing 200. After the battery undergoes thermal runaway and the internal temperature of the battery has not risen to the melting point of the plastic part, the plastic part maintains its pre-molten form to support the electrode group. At this time, the high-temperature and high-pressure gas in the accommodating cavity can be discharged to the explosion-proof valve through the vent holes, so that the explosion-proof valve opens and relieves pressure.

[0076] Furthermore, a relief groove is provided on the side of the plastic part facing the first side wall 210 of the housing 200, and the support platform 120 is embedded in the relief groove. Through the setting of the relief groove, the waste of space in the accommodating cavity can be avoided, the occupied space can be reduced, the volume of the electrode group can be increased, and it is beneficial to improve the energy density of the battery.

[0077] The remaining structures of the battery in this embodiment are the same as those in Embodiment 1, and will not be described in detail here.

[0078] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit 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 replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the claims of the present invention.

Claims

1. A battery, characterized in that: include: Explosion-proof valve; A cover plate body and a shell, wherein the cover plate body is connected to the shell and is surrounded to form a containing cavity, wherein at least one of the cover plate body and the shell is provided with a mounting hole and a supporting structure, wherein the mounting hole is used to mount the explosion-proof valve, and the supporting structure comprises a plurality of supporting platforms, wherein the plurality of supporting platforms are all arranged in the circumference of the mounting hole, and each of the supporting platforms is spaced apart from the mounting hole, and an exhaust passage is formed between two adjacent supporting platforms; A plastic part is arranged on a side of the cover body or the shell close to the accommodating cavity, and an end of the support platform away from the cover body or the shell abuts against the plastic part; The perimeter of the mounting hole is S1, the sum of the lengths of all the support platforms is S2, and S1 and S2 satisfy: 0.65≤S2 / S1≤1.

1.

2. The battery according to claim 1, characterized in that The mounting hole and the supporting structure are arranged on the cover body, the length of each supporting platform is S21, and the number of the supporting platforms is n; S2 and S21 satisfy: S2 = S21·n; Among them, the value range of S21 is: 10mm≤S21≤16mm.

3. The battery according to claim 2, characterized in that The width of the support platform is W, and the value range of W is: 5mm≤W≤8mm.

4. The battery according to claim 2, characterized in that Along the width direction of the cover body, the distance between the side of the support platform away from the mounting hole and the adjacent side edge of the cover body is A, and the size of the cover body is F; A and F satisfy: 0.12≤A / F≤0.2; The value range of A is: 5mm≤A≤10mm; The value range of F is: 25mm≤F≤75mm.

5. The battery according to claim 1, characterized in that The distance between the side of the support platform close to the mounting hole and the adjacent side of the mounting hole is D; The value range of D is: 4mm≤D≤6mm.

6. The battery according to claim 1, characterized in that The height of the support platform is H along a direction perpendicular to the end surface of the cover body or the shell; The value range of H is 3mm≤H≤5mm.

7. The battery according to claim 1, characterized in that When the battery is a ternary lithium system, S1 and S2 satisfy the following relationship: 0.85≤S2 / S1≤1.

1.

8. The battery according to claim 1, characterized in that When the battery is a lithium iron phosphate system, S1 and S2 satisfy the following relationship: 0.65≤S2 / S1≤0.

8.

9. The battery according to claim 1, characterized in that The plastic part is provided with a plurality of ventilation holes, which are arranged at intervals on the plastic part. Along a direction perpendicular to the end face of the cover body or the shell, the projections of the plurality of ventilation holes on the cover body or the shell at least partially overlap with the projections of the mounting holes on the cover body or the shell.

10. The battery according to claim 1, characterized in that A side of the plastic part facing the cover body or the shell is provided with an avoidance groove, and the support platform is embedded in the avoidance groove.

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