Battery cell cover plate assembly, battery cell, and battery pack

Abstract

The present application relates to the technical field of battery, and discloses a battery cell cover plate assembly, a battery cell and a battery pack. The battery cell cover plate assembly comprises a cover plate body and a burst valve. The cover plate body is provided with a pressure relief hole, which is a stepped hole comprising a first hole section, a second hole section and a third hole section, the inner diameter of which decreases from the first surface to the second surface in sequence, the side wall of the third hole section protrudes from the second surface to form a boss, and the cover plate body and the boss form a bent reinforcing structure; the burst valve is arranged in the second hole section; along the X direction, the outer diameter of the outer circle side wall of the boss is greater than or equal to the inner diameter of the first hole section, and the difference is 2y; along the Z direction, the distance from the hole bottom surface of the first hole section to the second surface is greater than the depth of the second hole section, and the difference is x; x and y satisfy a preset condition. The present application can solve the problem of burst valve tearing caused by the weak anti-deformation ability of the thin-wall cover plate, reduce the risk of burst valve failure, avoid battery cell liquid leakage, and improve the safety of the battery cell.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of batteries, in particular to a battery cell cover plate assembly, a battery cell and a battery pack. BACKGROUND

[0002] With the continuous development of technology, users have higher and higher requirements for new energy batteries. In order to improve the safety performance of the battery monomer, an explosion-proof valve is usually arranged on the battery monomer. When gas is generated inside the battery monomer due to abnormal operation, the gas can be discharged through the explosion-proof valve to avoid causing a major safety accident.

[0003] At present, the explosion-proof valve of the battery cell is located on the battery cell cover plate, and the thickness of the cover plate is gradually thinned in order to meet the demand of weight reduction and cost reduction in the industry. With the thinning of the thickness, the anti-deformation ability of the cover plate also decreases. During the charging and discharging cycle of the battery cell, as gas is generated inside the battery cell, the cover plate and the explosion-proof valve are deformed due to the internal gas pressure. The anti-deformation ability of the thinner cover plate decreases, which can exacerbate the deformation of the explosion-proof valve, pull the explosion-proof valve, cause the explosion-proof valve to tear at the notch, and cause the battery cell to leak. SUMMARY

[0004] Therefore, the present application provides a battery cell cover plate assembly, a battery cell and a battery pack to solve the problem that the anti-deformation ability of the thinner cover plate is weak, the cover plate and the explosion-proof valve are easily deformed, the explosion-proof valve is torn, and the battery cell leaks.

[0005] In a first aspect, the present application provides a battery cell cover plate assembly, comprising a cover plate body and an explosion-proof valve. In the Z direction, the cover plate body has a first surface and a second surface arranged oppositely, the cover plate body is provided with a pressure relief hole, the pressure relief hole is a stepped hole, comprising a first hole section, a second hole section and a third hole section, the inner diameter of which decreases successively from the first surface to the second surface, in the Z direction, the side wall of the third hole section protrudes from the second surface to form a boss, and the cover plate body and the boss form a bent reinforcing structure; the explosion-proof valve is arranged in the second hole section; in the X direction, the outer diameter of the outer circle side wall of the boss is greater than or equal to the inner diameter of the first hole section, and the difference is 2y, unit: mm; in the Z direction, the distance from the hole bottom surface of the first hole section to the second surface is greater than the depth of the second hole section, and the difference is x, unit: mm; and the following conditions are met:

[0006] ,

[0007] 0.1mm≤x≤1.6mm.

[0008] Beneficial Effects: The battery cell cover assembly provided by this invention, by providing a boss on the cover body, forms a bent reinforcing structure with the cover body and the boss. This improves the structural strength of the cover body near the pressure relief hole and enhances its resistance to deformation. While reducing weight and cost by thinning the cover body, it ensures high structural strength near the explosion-proof valve, preventing deformation and tearing of the explosion-proof valve when gas is generated inside the battery cell. This ensures the explosion-proof valve opens and releases pressure under normal pressure, reducing the risk of valve failure and improving the safety of the explosion-proof valve with the thin-walled cover. Furthermore, this invention limits the dimensional range of the reinforcing structure to meet the following requirements: With a thickness of 0.1mm≤x≤1.6mm, it effectively avoids the problem of easy tearing of explosion-proof valve caused by the reduction of weight of battery cell structural components, thinning of the cover plate body, and weakening of deformation resistance in the industry. It reduces the risk of explosion-proof valve failure, avoids battery cell leakage, and improves battery cell safety.

[0009] In one optional embodiment, along the Z direction, the thickness of the cover plate body is T (in mm), and the distance from the bottom surface of the first hole segment to the second surface is L (in mm); satisfying:

[0010] 0.5≤L / T≤0.95

[0011] 0.4mm≤L≤1.9mm,

[0012] 0.8mm≤T≤2mm.

[0013] In one optional implementation, the depth of the second hole segment along the Z direction is h2, in mm; satisfying:

[0014] h2+0.1mm<L.

[0015] In one optional implementation, along the Z direction, the depth of the first hole is h1 (mm), and the height of the boss protruding from the second surface is H (mm); satisfying:

[0016] 0.1mm≤H≤0.5mm

[0017] H≤h1.

[0018] In one alternative embodiment, a protective patch is further included, which is disposed within the first hole segment, or the protective patch is disposed on the first surface and projected along the Z direction, and the protective patch at least partially covers the explosion-proof valve.

[0019] In one optional implementation, the thickness of the protective patch along the Z direction is t1, in mm; and it also satisfies:

[0020] 0.1mm≤h1≤0.5mm,

[0021] t1≤0.3mm.

[0022] In one optional implementation, the thickness of the explosion-proof valve along the Z direction is t2, in mm; and it also satisfies:

[0023] 0mm≤h2-t2≤0.1mm,

[0024] 0.3mm≤t2≤0.6 mm,

[0025] 0.3mm≤h2≤0.7mm.

[0026] In one optional embodiment, the cover plate body is further provided with a first terminal assembly hole; the cell cover plate assembly also includes a riveting block, a terminal, a first insulating element, a second insulating element, and a sealing ring. The riveting block is provided with a second terminal assembly hole; the terminal includes a terminal body and a terminal base plate, the terminal body passes through the first terminal assembly hole and the second terminal assembly hole in sequence, and is riveted to the riveting block; the first insulating element is disposed between the riveting block and the first surface of the cover plate body, insulatingly connecting the riveting block and the cover plate body; the second insulating element is disposed between the terminal base plate and the second surface of the cover plate body, insulatingly connecting the terminal and the cover plate body; the sealing ring is sleeved on the terminal body, at least a portion of the sealing ring is located between the terminal body and the first terminal assembly hole, and at least another portion of the sealing ring is located between the terminal base plate and the cover plate body.

[0027] Secondly, the present invention also provides a battery cell, including a housing, an electrode assembly, and a battery cell cover assembly as described above. The housing has a receiving cavity and an opening communicating with the receiving cavity; the electrode assembly is disposed in the receiving cavity of the housing; the battery cell cover assembly is disposed in the opening of the housing, encapsulating the electrode assembly within the housing.

[0028] Beneficial Effects: The cell cover assembly is used in battery cells to seal the openings of the cell casing, sealing and protecting the internal components of the battery, preventing chemical leakage and the impact of the external environment on the battery. The terminals of the cell cover assembly provide the path for current inflow and outflow, ensuring current conduction during the charging and discharging process of the cell. For the battery cell, the cell cover assembly not only serves as an electrical connection but also enhances the overall structural stability of the cell, making it an important component that ensures the robustness and safety of the cell during use.

[0029] Since the battery cell includes the battery cell cover assembly, it has all the technical effects of the battery cell cover assembly, so it will not be elaborated here.

[0030] Thirdly, the present invention also provides a battery pack including multiple battery cells from more than one technical solution, wherein the riveting blocks of adjacent battery cells are welded together by a busbar.

[0031] Beneficial effects: Since the battery pack includes the cells, it has all the technical benefits of the cells, which will not be elaborated here. Attached Figure Description

[0032] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0033] Figure 1 This is a schematic diagram of the structure of a battery cell cover assembly according to an embodiment of the present invention;

[0034] Figure 2 for Figure 1 An exploded view of the battery cell cover assembly shown.

[0035] Figure 3 for Figure 1 A top view of the battery cell cover assembly shown;

[0036] Figure 4 For along Figure 3 Sectional view at point AA;

[0037] Figure 5 for Figure 4 A magnified view of a portion of the explosion-proof valve.

[0038] Figure 6 for Figure 4 A magnified view of the cover plate body at the pressure relief hole;

[0039] Figure 7 This is a cross-sectional view of another battery cell cover assembly at the explosion-proof valve according to an embodiment of the present invention;

[0040] Figure 8 This is a cross-sectional view of another battery cell cover assembly at the explosion-proof valve according to an embodiment of the present invention.

[0041] Explanation of reference numerals in the attached figures:

[0042] 1. Cover plate body; 101. Pressure relief hole; 1011. First hole section; 1012. Second hole section; 1013. Third hole section; 102. Boss; 103. First pole assembly hole; 11. First surface; 12. Second surface; 2. Explosion-proof valve; 3. Protective patch; 4. Riveting block; 401. Second pole assembly hole; 5. Pole; 501. Pole body; 502. Pole base plate; 6. First insulating component; 7. Second insulating component; 8. Sealing ring. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0044] Currently, to meet the industry's demand for weight reduction and cost reduction, the thickness of battery cell cover plates is gradually decreasing, from 3.0mm to 2.5mm, and even to 1.5mm, 1.2mm, and 1.0mm. With this reduction in thickness, the cover plate's resistance to deformation also decreases. Since explosion-proof valves are located on the battery cell cover plates, during the charge-discharge cycle, as gas is generated inside the cell, the cover plate and explosion-proof valve deform under the internal gas pressure. The reduced deformation resistance of the thinner cover plate exacerbates the deformation of the explosion-proof valve, pulling it and causing tearing at the valve's grooves, resulting in battery cell leakage.

[0045] To address the aforementioned technical problems of thin-walled cover plates, this invention provides a battery cell cover plate assembly. This assembly improves the structure of thin-walled cover plates equipped with explosion-proof valves, effectively mitigating the problem of battery cell leakage caused by deformation and tearing of the explosion-proof valve due to the weak structural strength and poor deformation resistance of thin-walled cover plates, thereby improving battery cell safety.

[0046] The following is combined with Figures 1 to 8 The following describes embodiments of the present invention.

[0047] According to an embodiment of the present invention, in a first aspect, a battery cell cover assembly is provided, comprising: a cover body 1 and an explosion-proof valve 2. Along the Z-direction, the cover plate body 1 has a first surface 11 and a second surface 12 disposed opposite to each other. The cover plate body 1 is provided with a pressure relief hole 101, which is a stepped hole including a first hole section 1011, a second hole section 1012, and a third hole section 1013 whose inner diameter decreases sequentially from the first surface 11 to the second surface 12. Along the Z-direction, the sidewall of the third hole section 1013 protrudes from the second surface 12 to form a boss 102. The cover plate body 1 and the boss 102 constitute a bent reinforcing structure. The explosion-proof valve 2 is disposed in the second hole section 1012. Along the X-direction, the outer diameter of the outer ring sidewall of the boss 102 is greater than or equal to the inner diameter of the first hole section 1011, and the difference is 2y (in mm). Along the Z-direction, the distance from the bottom surface of the first hole section 1011 to the second surface 12 is greater than the depth of the second hole section 1012, and the difference is x (in mm). The following conditions are met:

[0048] ,

[0049] 0.1mm≤x≤1.6mm.

[0050] The battery cell cover assembly provided by this invention has a pressure relief hole 101 in the cover body 1 configured as a stepped hole, with an explosion-proof valve 2 disposed within the second hole section 1012. The explosion-proof valve 2 can burst open to release pressure when internal gas is generated during battery cell operation and reaches the design pressure value. The first surface 11 of the cover body 1 is... Figures 4 to 8 The second surface 12 of the cover plate body 1 is represented by the upper surface of the cover plate body 1. Figures 4 to 8 This is represented by the lower surface of the cover plate body 1. For example... Figure 4 As shown, the Z direction is also the thickness direction of the cover plate body 1.

[0051] The cover plate body 1 and the boss 102 form a bent reinforcement structure; specifically, the cover plate body 1 and the boss 102 form a Z-shaped bent reinforcement structure. This can improve the structural strength of the cover plate body 1 near the pressure relief hole 101 and improve the deformation resistance of the cover plate body 1. This ensures that while the cover plate body 1 is thinned to reduce weight and cost, it also ensures that the cover plate body 1 has high structural strength near the explosion-proof valve 2. When gas is generated inside the battery cell, it is not easy to deform or pull the explosion-proof valve 2, thus avoiding tearing of the explosion-proof valve 2 and ensuring that the explosion-proof valve 2 opens and releases pressure under normal pressure value. This reduces the risk of failure of the explosion-proof valve 2 and improves the safety of the explosion-proof valve 2 of the thin-walled cover plate.

[0052] Along the X direction, the outer diameter of the outer ring sidewall of the boss 102 is greater than or equal to the inner diameter of the first hole segment 1011. That is, when projected along the Z direction, the sidewall of the first hole segment 1011 does not exceed the projection range of the boss 102.

[0053] Along the X direction, the difference between the outer diameter of the outer ring sidewall of the boss 102 and the inner diameter of the first hole segment 1011 is 2y. Since the distances on both sides of the boss 102 and the first hole segment 1011 are equal, the difference on one side is y. For ease of description, the difference y between the outer diameter of the outer ring sidewall of the boss 102 and the inner diameter of the first hole segment 1011 along the X direction is defined as the width of the reinforcing rib, and the difference x between the distance from the bottom surface of the first hole segment 1011 to the second surface 12 and the depth of the second hole segment 1012 along the Z direction is defined as the thickness of the reinforcing rib. The width y and the thickness x of the reinforcing rib must satisfy the above formula.

[0054] The battery cell cover assembly provided in this embodiment of the invention has the aforementioned reinforcing structure provided around the pressure relief hole 101 on the cover body 1. Simultaneously, the thickness x of the reinforcing rib and the dimensional relationship between the width and thickness of the reinforcing rib are defined to satisfy: 0.1mm ≤ x ≤ 1.6mm. Otherwise, based on the thickness x of the stiffener, if If the distance is too small, that is, the sidewall of the first hole segment 1011 is too close to the outer ring sidewall of the boss 102, resulting in an overly weak reinforced structure, which may even weaken the structural strength at this point. If the distance is too large, the reinforced structure will be too wide, resulting in an insignificant reinforcing effect on the pressure relief hole 101, and thus failing to provide a buffering effect. Therefore, by satisfying the above relationship, the reinforced structure can significantly strengthen the cover plate body 1 structure near the pressure relief hole 101, effectively avoiding the problem of easy tearing of the explosion-proof valve 2 caused by the reduction in weight of the battery cell structural components, thinning of the cover plate body 1, and weakening of deformation resistance, thus reducing the risk of failure of the explosion-proof valve 2, preventing battery cell leakage, and improving the safety of the battery cell.

[0055] In such Figure 5 In the embodiment shown, the outer diameter of the outer ring sidewall of the boss 102 is equal to the inner diameter of the first hole segment 1011, i.e., y=0mm.

[0056] In such Figure 7 In the embodiment shown, the outer diameter of the outer ring sidewall of the boss 102 is greater than the inner diameter of the first hole segment 1011, i.e., y > 0 mm.

[0057] In addition, in the battery cell cover assembly provided by the present invention, the explosion-proof valve 2 is disposed in the second hole section 1012. The explosion-proof valve 2 is welded from the outside of the battery cell, which can prevent welding slag from falling into the battery cell and piercing the electrode group, and avoid damage to the electrode group by welding slag.

[0058] In some embodiments, along the Z direction, the thickness of the cover plate body 1 is T, in mm, and the distance from the bottom surface of the first hole segment 1011 to the second surface 12 is L, in mm; satisfying:

[0059] 0.5≤L / T≤0.95

[0060] 0.4mm≤L≤1.9mm,

[0061] 0.8mm≤T≤2mm.

[0062] Reference Figure 6 The structure of the cell cover plate assembly provided by the present invention is suitable for thinning the cover plate. The thickness T of the cover plate body 1 is between 0.8mm and 2mm, which can meet the industry's demand for weight reduction and cost reduction.

[0063] By controlling the ratio of the distance L from the bottom surface of the first hole segment 1011 to the second surface 12 to the thickness T of the cover plate body 1 within the range of 0.5 to 0.95, the thickness of the reinforcing rib structure can be kept within a reasonable range. This significantly strengthens the structure near the pressure relief hole 101 of the cover plate body 1, ensuring the buffering and deformation resistance of the cover plate body 1 near the pressure relief hole 101. Simultaneously, the first hole segment 1011 retains sufficient depth for installing the protective patch of the explosion-proof valve 2.

[0064] When the thickness T of the cover plate body 1 is controlled within the range of 0.8mm to 2mm, the corresponding distance L from the bottom surface of the first hole section 1011 to the second surface 12 is within the range of 0.4mm to 1.9mm.

[0065] In some embodiments, along the Z direction, the depth of the second hole segment 1012 is h2, in mm; satisfying:

[0066] h2+0.1mm<L.

[0067] Specifically, the depth h2 of the second hole section 1012 is less than L - 0.1 mm, which ensures that the second hole section 1012 has a suitable forming depth, is easy to process, and meets the installation requirements of the explosion-proof valve 2.

[0068] In some embodiments, along the Z direction, the depth of the first hole segment 1011 is h1 (in mm), and the height of the boss 102 protruding from the second surface 12 is H (in mm); satisfying:

[0069] 0.1mm≤H≤0.5mm

[0070] H≤h1.

[0071] Reference Figure 3 The pressure relief hole 101 is a track-track shaped hole structure. The boss 102 is adapted to the shape of the pressure relief hole 101 and is an annular structure arranged around the pressure relief hole 101. The annular cavity defined by the inner sidewall of the boss 102 constitutes the third hole segment 1013, which is connected to the second hole segment 1012.

[0072] In this embodiment, the height H of the boss 102 protruding from the second surface 12 is controlled within the range of 0.1mm to 0.5mm, which can form a Z-shaped reinforcing structure with the cover plate body 1, thereby improving the deformation resistance of the cover plate body 1 around the pressure relief hole 101; at the same time, it avoids the boss 102 protruding too high, which would significantly increase the weight of the cover plate body 1.

[0073] In some embodiments, a protective patch 3 is also included, which is disposed within the first hole segment 1011, or the protective patch 3 is disposed on the first surface 11 and projected along the Z direction, and the protective patch 3 at least partially covers the explosion-proof valve 2.

[0074] Projecting along the Z-axis, the projection of the protective patch 3 partially overlaps with the projection of the explosion-proof valve 2. The protective patch 3 is used to protect the explosion-proof valve 2, prevent the explosion-proof valve 2 from being scratched or bumped, and ensure that the explosion-proof valve 2 can open normally to release pressure when the internal air pressure of the battery cell reaches the design pressure value.

[0075] The protective patch 3 can be disposed in the first hole section 1011. At this time, the protective patch 3 is attached to the bottom wall of the first hole section 1011, that is, the step surface between the first hole section 1011 and the second hole section 1012.

[0076] The protective patch 3 can also be disposed on the first surface 11 of the cover plate body 1, such as Figure 8 As shown.

[0077] In some embodiments, the thickness of the protective patch 3 along the Z direction is t1, in mm; and it also satisfies:

[0078] 0.1mm≤h1≤0.5mm,

[0079] t1≤0.3mm.

[0080] The thickness t1 of the protective patch 3 should not exceed 0.3mm; otherwise, a thicker protective patch 3 will increase the response speed of the explosion-proof valve 2, leading to a reduction in the safety of the battery cell. In addition, it will occupy more space, increase the difficulty of installation, and increase material costs.

[0081] The protective patch 3 can be installed within the first hole section 1011, and the depth h1 of the first hole section 1011 is controlled within the range of 0.1mm to 0.5mm. If the depth h1 of the first hole section 1011 is large, it will result in a smaller depth of the second hole section 1012, which will affect the installation of the explosion-proof valve 2 and will also prevent the internal pressure of the battery cell from being quickly transmitted to the protective patch 3, thus affecting the pressure relief response speed of the explosion-proof valve 2. If the depth h1 of the first hole section 1011 is small, it will affect the feasibility of hole depth processing.

[0082] In some embodiments, the thickness of the explosion-proof valve 2 along the Z direction is t2, in mm; and it also satisfies:

[0083] 0mm≤h2-t2≤0.1mm,

[0084] 0.3mm≤t2≤0.6 mm,

[0085] 0.3mm≤h2≤0.7mm.

[0086] Specifically, the explosion-proof valve 2 is located within the second orifice section 1012. The depth h2 of the second orifice section 1012 must be greater than or equal to the thickness t2 of the explosion-proof valve 2, but the difference must not exceed 0.1 mm. Otherwise, it would be detrimental to the installation of the explosion-proof valve 2 and the thinning design of the cover plate body 1. Since 0.3 mm ≤ t2 ≤ 0.6 mm, therefore, 0.3 mm ≤ h2 ≤ 0.7 mm.

[0087] In some embodiments, the cover plate body 1 is further provided with a first terminal post mounting hole 103; the cell cover plate assembly further includes a riveting block 4, a terminal post 5, a first insulating member 6, a second insulating member 7, and a sealing ring 8. The riveting block 4 is provided with a second terminal post mounting hole 401; the terminal post 5 includes a terminal post body 501 and a terminal post base plate 502, the terminal post body 501 passes through the first terminal post mounting hole 103 and the second terminal post mounting hole 401 in sequence, and is riveted to the riveting block 4; the first insulating member 6 is disposed between the riveting block 4 and the first surface 11 of the cover plate body 1, insulatingly connecting the riveting block 4 and the cover plate body 1; the second insulating member 7 is disposed between the terminal post base plate 502 and the second surface 12 of the cover plate body 1, insulatingly connecting the terminal post 5 and the cover plate body 1; the sealing ring 8 is sleeved on the terminal post body 501, at least a portion of the sealing ring 8 is located between the terminal post body 501 and the first terminal post mounting hole 103, and at least another portion of the sealing ring 8 is located between the terminal post base plate 502 and the cover plate body 1.

[0088] Specifically, the pole post 5 and the rivet block 4 are riveted and then welded together to achieve a fixed connection between the cover plate body 1, the pole post 5 and the rivet block 4.

[0089] In this embodiment, the riveting block 4 and the first surface 11 of the cover plate body 1 are insulated from each other by a first insulating member 6, and the pole base plate 502 and the second surface 12 of the cover plate body 1 are insulated from each other by a second insulating member 7. Further, in some embodiments, both the first insulating member 6 and the second insulating member 7 are made of plastic. The first insulating member 6 and the second insulating member 7 are used to ensure insulation between the cover plate body 1 and the riveting block 4, and between the cover plate body 1 and the pole 5, thereby preventing short circuits or leakage in the battery cell and improving the safety and reliability of the battery cell.

[0090] In this embodiment, the sealing ring 8 can form a double seal between the pole post 5 and the cover plate body 1 along the axial and radial directions of the pole post 5, thereby improving the sealing performance, reliability and safety of the battery cell.

[0091] To verify the technical effect of the present invention, specific experimental cases are provided below, including embodiments and comparative examples, and the number of breathing fatigue cycles of the explosion-proof valve 2 are tested in each case.

[0092] Specifically, when the cover plate body 1 has weak deformation resistance, gas is generated inside the battery cell during charge-discharge cycles, resulting in internal pressure and causing deformation of both the cover plate body 1 and the explosion-proof valve 2. Furthermore, the deformation of the cover plate body 1 also causes deformation of the explosion-proof valve 2, leading to fatigue deformation. While reinforcing structures can alleviate the deformation of the explosion-proof valve 2 caused by the cover plate body 1, if the reinforcing structure is too weak, it cannot effectively mitigate the deformation. Consequently, the number of fatigue cycles of the explosion-proof valve 2 decreases, making it prone to cracking. In other words, the number of fatigue cycles of the explosion-proof valve 2 cannot meet the cycle life requirements of the battery cell, posing a risk. Therefore, the number of fatigue cycles of the explosion-proof valve 2 is used here to reflect the strengthening effect of the reinforcing structure on the overall strength of the cover plate body 1.

[0093] The test method for the number of breathing fatigue cycles of the explosion-proof valve 2 adopts a method known to those skilled in the art, and the following is an example.

[0094] Test equipment and principles:

[0095] Exhaust fatigue testing of the explosion-proof valve 2 typically employs specialized testing equipment, such as a cover explosion-proof valve 2 breathing cycle tester. These devices assess the durability of the power battery's explosion-proof valve 2 by simulating the fatigue environment of the battery in actual use. The tester can apply periodic pressure changes to detect the performance and safety of the explosion-proof valve 2 during long-term use.

[0096] Test steps:

[0097] Pressure Cycle Test: A single cell cover assembly is used, which is constrained vertically and tightly sealed using tooling. A sealed gas chamber is formed at explosion-proof valve 2. Gas enters the sealed gas chamber through the channel, applying pressure to explosion-proof valve 2. The pressure is increased from near zero pressure to the maximum gas generation pressure during the simulated cell charge-discharge cycle (e.g., 0.5 MPa), then the pressure drops to zero, and then increases back to 0.5 MPa. This pressure cycle is repeated, typically for no less than 2000 cycles, with a frequency controlled below 10 cycles / minute. The pressure is maintained for at least 1.2 seconds during the period of 90%-100% of the maximum pressure.

[0098] Result evaluation: The requirement is met if the cell life cycle is ≥2000 cycles. That is, the number of breathing fatigue cycles of explosion-proof valve 2 is denoted as N, and N≥2000 is required, which meets the requirement.

[0099] The test results are detailed in Table 1.

[0100] Table 1

[0101]

[0102] As shown in Table 1, in Examples 1 to 10, the values ​​of y and x and their relationship satisfy the following... 0.1mm≤x≤1.6mm. The reinforced structure can buffer deformation, reduce the pulling effect of the cover plate body 1 on the explosion-proof valve 2 when the battery cell generates gas, improve the fatigue deformation resistance of the explosion-proof valve 2, increase the number of breathing fatigue cycles, and meet the requirements of the entire life cycle of the battery cell.

[0103] In Comparative Examples 5 and 6, x is too small, that is, the thickness of the reinforcing rib is too small, and the reinforcing structure is too weak. During the test, the explosion-proof valve 2 deforms, which reduces the number of breathing fatigue cycles of the explosion-proof valve 2, resulting in the explosion-proof valve 2 failing the breathing fatigue cycle test and not meeting the requirements of the entire life cycle of the battery cell.

[0104] In Comparative Examples 7 and 8, the width y of the reinforcing rib was too small due to the thickness x of the reinforcing rib, resulting in an excessively weak reinforced structure. During the test, the explosion-proof valve 2 deformed, reducing the number of breathing fatigue cycles of the explosion-proof valve 2. Consequently, the breathing fatigue cycle test of the explosion-proof valve 2 failed, failing to meet the requirements of the entire life cycle of the battery cell.

[0105] In Comparative Examples 9 and 10, the width y of the reinforcing rib is too large due to the thickness x of the reinforcing rib. This results in the reinforced structure not having a significant reinforcing effect on the pressure relief hole 101 and failing to provide a buffering effect. This reduces the number of breathing fatigue cycles of the explosion-proof valve 2, causing the explosion-proof valve 2 to fail the breathing fatigue cycle test and not meet the requirements of the entire life cycle of the battery cell.

[0106] In Comparative Examples 3 and 4, the ratio of the distance L from the bottom surface of the first hole segment 1011 to the second surface 12 to the thickness T of the cover plate body 1 is too small, the reinforcing structure is too weak, the explosion-proof valve 2 deforms during the test, the number of breathing fatigue cycles of the explosion-proof valve 2 is reduced, resulting in the explosion-proof valve 2 failing the breathing fatigue cycle test and not meeting the requirements of the entire life cycle of the battery cell.

[0107] In Comparative Examples 1 and 2, the depth h1 of the first hole segment 1011 is too small, and the ratio of the distance L from the bottom surface of the first hole segment 1011 to the thickness T of the cover plate body 1 is too large. The resulting reinforcing structure does not significantly strengthen the pressure relief hole 101 and cannot play a buffering role, resulting in the explosion-proof valve 2 failing the breathing fatigue test and not meeting the requirements of the entire life cycle of the battery cell.

[0108] According to an embodiment of the present invention, in a second aspect, a battery cell is also provided, including a housing, an electrode assembly, and a battery cell cover assembly as described in the above embodiments. The housing has a receiving cavity and an opening communicating with the receiving cavity; the electrode assembly is disposed in the receiving cavity of the housing; the battery cell cover assembly is disposed in the opening of the housing, encapsulating the electrode assembly within the housing.

[0109] The cell cover assembly is used in battery cells to seal the openings in the cell casing, serving to seal and protect the internal components of the battery, preventing chemical leakage and the impact of the external environment on the battery. The terminal post 5 of the cell cover assembly provides a path for current inflow and outflow, ensuring current conduction during the cell's charging and discharging processes. For the battery cell, the cell cover assembly not only provides electrical connections but also enhances the overall structural stability of the cell, making it a crucial component that ensures the cell's robustness and safety during use.

[0110] Since the battery cell includes the battery cell cover assembly, it has all the technical effects of the battery cell cover assembly, so it will not be elaborated here.

[0111] In some embodiments, the battery cell includes a blade cell.

[0112] According to an embodiment of the present invention, in a third aspect, a battery pack is also provided, comprising a plurality of battery cells as described in the above embodiments, wherein the riveting blocks 4 of adjacent battery cells are welded together via a busbar.

[0113] Since the battery pack includes the battery cells and has all the technical benefits of the battery cells, it will not be elaborated here.

[0114] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A cell cover assembly, characterized in that, include: The cover plate body has a first surface and a second surface arranged opposite to each other along the Z direction. The cover plate body is provided with a pressure relief hole, which is a stepped hole, including a first hole segment, a second hole segment and a third hole segment whose inner diameter decreases sequentially from the first surface to the second surface. Along the Z direction, the sidewall of the third hole segment protrudes from the second surface to form a boss. The cover plate body and the boss constitute a bent reinforcing structure. An explosion-proof valve is disposed within the second orifice section; Along the X direction, the outer diameter of the outer ring sidewall of the boss is greater than or equal to the inner diameter of the first hole segment, and the difference is 2y, in mm; Along the Z direction, the distance from the bottom surface of the first hole segment to the second surface is greater than the depth of the second hole segment, and the difference is x, in mm; satisfy: ， 0.1mm≤x≤1.6mm.

2. The cell cover assembly according to claim 1, characterized in that, Along the Z direction, the thickness of the cover plate body is T, in mm, and the distance from the bottom surface of the first hole section to the second surface is L, in mm. satisfy: 0.5≤L / T≤0.95 0.4mm≤L≤1.9mm, 0.8mm≤T≤2mm.

3. The cell cover assembly according to claim 2, characterized in that, Along the Z direction, the depth of the second hole segment is h2, in mm; satisfy: h2+0.1mm<L.

4. The cell cover assembly according to claim 1, characterized in that, Along the Z direction, the depth of the first hole is h1, in mm, and the height of the boss protruding from the second surface is H, in mm. satisfy: 0.1mm≤H≤0.5mm, H≤h1.

5. The cell cover assembly according to claim 4, characterized in that, It also includes a protective patch, which is disposed within the first hole segment, or the protective patch is disposed on the first surface and projected along the Z direction, and the protective patch at least partially covers the explosion-proof valve.

6. The cell cover assembly according to claim 5, characterized in that, Along the Z direction, the thickness of the protective patch is t1, in mm; Also satisfies: 0.1mm≤h1≤0.5mm, t1≤0.3mm.

7. The cell cover assembly according to claim 3, characterized in that, Along the Z direction, the thickness of the explosion-proof valve is t2, in mm; Also satisfies: 0mm≤h2-t2≤0.1mm, 0.3mm≤t2≤0.6 mm, 0.3mm≤h2≤0.7mm.

8. The cell cover assembly according to claim 1, characterized in that, The cover plate body is also provided with a first pole post assembly hole; The cell cover assembly also includes: A riveting block, wherein the riveting block is provided with a second pole assembly hole; The pole includes a pole body and a pole base plate. The pole body passes through the first pole assembly hole and the second pole assembly hole in sequence and is then riveted to the riveting block. A first insulating element is disposed between the riveting block and the first surface of the cover plate body, thereby insulatingly connecting the riveting block and the cover plate body. The second insulating element is disposed between the base plate of the pole post and the second surface of the cover plate body, thereby insulatingly connecting the pole post and the cover plate body. A sealing ring is fitted onto the pole body, at least a portion of which is located between the pole body and the first pole mounting hole, and at least another portion of which is located between the pole base plate and the cover plate body.

9. A battery cell, characterized in that, include: A housing having a receiving cavity and an opening communicating with the receiving cavity; A pole assembly, wherein the pole assembly is disposed in the receiving cavity of the housing; The cell cover assembly according to any one of claims 1 to 8, wherein the cell cover assembly is disposed at the opening of the housing and encapsulates the electrode assembly within the housing.

10. A battery pack, characterized in that, The battery includes multiple battery cells as described in claim 9, wherein the riveting blocks of adjacent battery cells are welded together via a busbar.

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