Battery monomer, battery pack and electric equipment

Abstract

The invention relates to the technical field of batteries, in particular to a battery monomer, a battery pack and electric equipment. The embodiment of the invention provides a battery monomer which comprises a shell, a battery cell, an insulating part and an anti-explosion valve, and the shell is provided with a first wall; the battery cell is arranged in the shell; the insulating part is arranged between the first wall and the battery cell along the thickness direction of the first wall, the insulating part is provided with a plurality of through holes arranged at intervals, the through holes penetrate through the insulating part along the thickness direction of the first wall, the projection area of each through hole is S1 mm < 2 >, and the sum of the projection areas of the plurality of through holes is S2 mm < 2 >; the anti-explosion valve is arranged on the first wall, and in the thickness direction of the first wall, the projections of the through holes at least partially coincide with the projection of the anti-explosion valve; wherein in the thickness direction of the first wall, the projection area of the first wall is S3 mm < 2 >, the breaking strength of the insulating part is K, and K * S1 * S2 / S3 is larger than or equal to 4 and smaller than or equal to 17615. The anti-explosion structure can reduce the blockage of the anti-explosion valve, improve the exhaust performance of the battery cell, and reduce the risk of lap joint of the battery cell and the shell.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of batteries, in particular to a battery monomer, a battery pack and an electric device. BACKGROUND

[0002] An explosion-proof valve is arranged on the battery shell, and the explosion-proof valve is opened when the battery is in thermal runaway, and high-pressure gas in the battery cell is discharged from the explosion-proof valve to release pressure of the battery. In the related art, the battery cell is prone to swelling during use of the battery, and the swollen battery cell squeezes the lower plastic, causing the lower plastic to deform and block the explosion-proof valve, thereby affecting the pressure relief of the explosion-proof valve. SUMMARY

[0003] The present application provides a battery monomer, a battery pack and an electric device, which can reduce the blockage of the explosion-proof valve, improve the exhaust performance of the battery cell, and reduce the risk of the battery cell and the shell being overlapped.

[0004] To achieve the above purpose, the main technical scheme adopted by the present application includes: In a first aspect, the present application provides a battery monomer, comprising a shell, a battery cell, an insulating member and an explosion-proof valve, the shell having a first wall; the battery cell is arranged in the shell; along the thickness direction of the first wall, the insulating member is arranged between the first wall and the battery cell, the insulating member has a plurality of spaced-apart through holes, along the thickness direction of the first wall, the through holes penetrate the insulating member, the projection area of each through hole is S1mm 2 , the sum of the projection areas of the plurality of through holes is S2mm 2 ; the explosion-proof valve is arranged on the first wall, along the thickness direction of the first wall, the projection of the plurality of through holes at least partially overlaps with the projection of the explosion-proof valve; wherein, along the thickness direction of the first wall, the projection area of the first wall is S3mm 2 , the breaking strength of the insulating member is Kkv / mm, and satisfies: 4≤K×S1×S2 / S3≤17615.

[0005] The battery cell proposed in this application has an insulating component disposed between the first wall and the battery cell. This insulating component has good support properties, effectively separating the battery cell from the casing and reducing the risk of insulation failure due to the battery cell expanding and contacting the first wall. Simultaneously, along the thickness direction of the first wall, the projections of multiple through holes at least partially overlap with the projection of the explosion-proof valve. These through holes on the insulating component are at least partially opposite to the explosion-proof valve, allowing for rapid convergence of the gas emitted from the battery cell to the explosion-proof valve in the event of thermal runaway. This rapidly increases the gas pressure around the explosion-proof valve, facilitating its rapid opening and thus rapid depressurization of the battery cell, reducing the likelihood of more severe thermal runaway. In this application, limiting the value of K×S1×S2 / S3 ensures the insulating component has good deformation resistance and reduces the risk of blockage of the through holes, thereby minimizing the risk of battery cell bridging with the casing. If the value of K×S1×S2 / S3 is too small, it means that the size of the through hole in the insulation component is too small. Under high temperature conditions, the through hole in the insulation component is easily blocked, which prevents the gas in the cell from escaping and the explosion-proof valve from opening in time, thus causing more serious thermal runaway. If the value of K×S1×S2 / S3 is too large, it means that the size of the through hole is too large, and the cell can easily pass through the through hole and overlap with the shell, thereby increasing the risk of short circuit.

[0006] Secondly, embodiments of this application provide a battery pack comprising the battery cells described in any of the above embodiments.

[0007] The battery pack proposed in this application includes individual battery cells and has the same beneficial effects as individual battery cells.

[0008] Thirdly, embodiments of this application provide an electrical device, including a single battery cell as described in any of the above embodiments or a battery pack as described in the above embodiments.

[0009] The electrical equipment proposed in this application has the beneficial effects of the battery cells and battery packs described in any of the above embodiments. Attached Figure Description

[0010] To more clearly illustrate the technical solutions in the specific embodiments of this application or 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 this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0011] Figure 1 This is a cross-sectional view of a single battery cell in one embodiment of this application; Figure 2 This is an exploded view of a single battery cell in one embodiment of this application; Figure 3 This is a schematic diagram of the structure of the insulating element in one embodiment of this application; Figure 4 This is a cross-sectional view of a battery cell in another embodiment of this application; Figure 5 This is a cross-sectional view of a single battery cell in yet another embodiment of this application; Figure 6 for Figure 1 A magnified view of region B in the middle.

[0012] [Explanation of Labels in the Attached Image] 1. Shell; 11. First wall; 12. Injection hole; 13. Second wall; 14. Third wall; 2. Battery cell; 21. Battery cell body; 22. Electrode tab; 3. Insulating component; 31. Through hole; 32. First surface; 33. Body part; 34. Protrusion; 341. Peripheral wall; 342. Bottom wall; 35. First clearance hole; 36. Second clearance hole; 4. Explosion-proof valve; 5. Electrode terminals; X, the thickness direction of the first wall; Y, the first direction. Detailed Implementation

[0013] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0014] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the description of this application is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms "comprising" and "having," and any variations thereof, in the description, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the description, claims, or accompanying drawings of this application are used to distinguish different objects, not to describe a specific order or hierarchy.

[0015] In this application, the reference to "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described in this application can be combined with other embodiments.

[0016] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "attachment" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0017] In this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, in this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0018] In this application, "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0019] The battery described in this application is a secondary battery, also known as a rechargeable battery or accumulator, which refers to a battery that can be recharged after discharge to activate its active materials and continue to be used. Typically, a secondary battery includes an electrode assembly, an electrolyte, and a casing. The electrode assembly includes a positive electrode, a negative electrode, and a separator. The electrode assembly and electrolyte are assembled within the outer casing. During charging and discharging, active ions (such as lithium ions) move back and forth between the positive and negative electrodes, inserting and extracting. The separator is positioned between the positive and negative electrodes, primarily serving to prevent short circuits and allowing active ions to pass through. The electrolyte, located between the positive and negative electrodes, primarily functions to conduct active ions.

[0020] The housing is a component used to provide a space to house electrode assemblies and other parts, isolating them from the external environment. The housing typically includes a body with an opening at at least one end and a receiving cavity. The opening can be closed with a cover plate, sealing and isolating the internal environment of the battery cell from the external environment. The housing can be made of metals such as copper, iron, aluminum, stainless steel, or aluminum alloy.

[0021] In related technologies, an explosion-proof valve needs to be installed on the battery casing. When the battery experiences thermal runaway, the high-temperature and high-pressure gas inside the cell breaks through the explosion-proof valve and is discharged outward. However, because the cell is prone to expansion during battery use, the expanded cell will squeeze the lower plastic, causing the lower plastic to deform. This makes it easy for the cell to block the venting channel of the lower plastic, thereby blocking the explosion-proof valve and affecting the opening of the explosion-proof valve to release pressure.

[0022] Firstly, reference Figures 1 to 5 This application provides a battery cell comprising a housing 1, a battery cell 2, an insulating component 3, and an explosion-proof valve 4. The housing 1 has a first wall 11. The battery cell 2 is disposed within the housing 1. Along the thickness direction X of the first wall 11, the insulating component 3 is disposed between the first wall 11 and the battery cell 2. The insulating component 3 has a plurality of spaced through holes 31 that penetrate the insulating component 3 along the thickness direction X of the first wall 11. The projected area of ​​each through hole 31 is S1 mm. 2 The sum of the projected areas of the multiple through holes 31 is S2mm. 2 The explosion-proof valve 4 is disposed on the first wall 11. Along the thickness direction X of the first wall 11, the projections of the plurality of through holes 31 at least partially coincide with the projection of the explosion-proof valve 4; wherein, along the thickness direction X of the first wall 11, the projected area of ​​the first wall 11 is S3mm. 2 The breaking strength of insulating component 3 is Kkv / mm, which satisfies: 4≤K×S1×S2 / S3≤17615.

[0023] The casing 1 forms the outer contour of the battery and protects the battery cell 2 and other components inside the casing 1. A receiving cavity is provided inside the casing 1, within which the battery cell 2 and the insulating component 3 are located. The battery cell 2 can be a stacked battery cell 2, having positive and negative electrode plates stacked on top of each other, and a separator disposed between the positive and negative electrode plates, thus allowing multiple pairs of positive and negative electrode plates to be stacked to form a stacked battery cell 2. Alternatively, the battery cell 2 can be a wound battery cell 2, in which the positive and negative electrode plates and the separator disposed between the positive and negative electrode plates are wound to obtain a wound battery cell 2.

[0024] An insulating component 3 is disposed between the battery cell 2 and the housing 1 to insulate the battery cell 2 from the housing 1 (bottom surface) and to reduce the risk of short circuits. The insulating component 3 can be made of plastic, rubber, or other insulating materials. The plastic can be polyethylene terephthalate (PET), polypropylene (PP), polycarbonate (PC), or polyvinyl chloride (PVC), and the rubber can be fluororubber, nitrile rubber, or isobutyl rubber, etc.

[0025] An insulating member 3 is disposed between the first wall 11 and the battery cell 2 to separate the battery cell 2 from the housing 1. The insulating member 3 has multiple through holes 31 for pressure relief, which connect the battery cell 2 to the explosion-proof valve 4 in the event of battery thermal runaway. By separating the battery cell 2 from the housing 1 through the insulating member 3, the problem of the diaphragm or electrode plates in the battery cell 2 blocking the explosion-proof valve 4 when the battery cell 2 and housing 1 come into contact is reduced, thus preventing the battery from depressurizing in a timely manner. The size of each through hole 31 can be the same or different; in other words, the projected areas of each through hole 31 can be equal or unequal, and this application is not limited to this.

[0026] An explosion-proof valve 4 refers to a component or part that can be actuated to release internal pressure or temperature when the internal pressure or temperature of a battery cell reaches a predetermined threshold. During battery use, the explosion-proof valve 4 is mainly used to allow gas to escape from the battery and reduce internal pressure in cases of thermal runaway, preventing excessive pressure buildup that could cause deformation or explosion. The material of the explosion-proof valve 4 is not limited, including but not limited to aluminum, steel, and alloys. The shape of the explosion-proof valve 4 is not limited, such as square, oblong, elliptical, racetrack-shaped, etc. The type of explosion-proof valve 4 is not limited, such as a notched explosion-proof valve 4, which can be formed by stamping or laser etching.

[0027] For example, the scribing can be a closed scribing such as a circle or an ellipse, or it can be a non-closed scribing, such as a cross-shaped scribing, a "C"-shaped scribing, etc. The embodiments of this application are not limited thereto. The explosion-proof valve 4 is disposed on the first wall 11 of the housing 1. The first wall 11 can be the top wall, bottom wall 342 or side wall of the housing 1.

[0028] In this application, the test method for insulation strength K is as follows: the battery is discharged at 0.33C to the lower limit voltage, disassembled, and the insulating component 3 is removed. After the insulating component 3 is placed at 120℃ for 10 minutes, a voltage is applied to both sides of the insulating component 3 in the thickness direction, with a voltage rise rate of 500V / s. When the current through the insulating component 3 is greater than 10mA, this voltage is maintained for 60 seconds. If the current does not increase, the voltage at this time is recorded as V. The thickness of the insulating component 3 is measured as H using a micrometer. The insulation strength K = V / H. Specifically, when the positive electrode active material of the battery is a nickel-cobalt-manganese ternary cathode, the upper limit voltage is 4.25V and the lower limit voltage is 2.5V; when the positive electrode active material of the battery is lithium iron phosphate, the upper limit voltage is 3.6V and the lower limit voltage is 2.5V.

[0029] The projected area S1 of the through hole 31 is the area of ​​the through hole 31. The testing method is as follows: Discharge the battery to the lower limit voltage at 0.33C, disassemble it, remove the insulating component 3, place the insulating component 3 at 120℃ for 10 minutes, measure the size of the through hole 31 with a micrometer, and calculate the area as S1. The unit is mm.2 .

[0030] The sum of the projected areas S2 of the multiple through holes 31 is the sum of the areas of the multiple through holes 31. The test method is as follows: add up the areas of the multiple through holes 31, and the resulting value is S2, with the unit being mm. 2 .

[0031] The projected area S3 of the first wall 11 is the area of ​​the first wall 11. The testing method is as follows: measure the length and width of the first wall 11 of the shell 1 with a micrometer, and calculate S3 using the formula S3 = length × width. The unit is mm. 2 .

[0032] In the battery cell proposed in this application embodiment, the insulating component 3 is disposed between the first wall 11 and the battery cell 2. The insulating component 3 has good support performance, which can separate the battery cell 2 and the housing 1, reducing the risk of insulation failure due to contact between the battery cell 2 and the first wall 11 after expansion. At the same time, along the thickness direction X of the first wall 11, the projections of multiple through holes 31 at least partially coincide with the projection of the explosion-proof valve 4. The multiple through holes 31 on the insulating component 3 are at least partially opposite to the explosion-proof valve 4, which can quickly gather the gas discharged from the battery cell 2 to the explosion-proof valve 4 when thermal runaway occurs, so as to rapidly increase the gas pressure around the explosion-proof valve 4, which facilitates the rapid opening of the explosion-proof valve 4, thereby realizing rapid pressure relief of the battery cell 2 and reducing the occurrence of more serious thermal runaway. In this application, by limiting the value of K×S1×S2 / S3, the insulating component 3 has better resistance to deformation and can reduce the blockage of the through holes 31 on the insulating component 3, thereby reducing the risk of battery cell 2 overlapping with housing 1. If the value of K×S1×S2 / S3 is too small, it means that the size of the through hole 31 of the insulating component 3 is small. Under high temperature conditions, the through hole 31 on the insulating component 3 is easily blocked, which prevents the gas in the cell 2 from being discharged and the explosion-proof valve 4 from opening in time, thus causing more serious thermal runaway. If the value of K×S1×S2 / S3 is too large, it means that the size of the through hole 31 is large, and the cell 2 can easily pass through the through hole 31 and overlap with the shell 1, thereby increasing the risk of short circuit.

[0033] The value of K×S1×S2 / S3 can be 4, 8, 10, 20, 50, 100, 500, 1000, 2000, 3000, 5000, 6000, 7000, 8000, 9000, 10000, 11000, 12000, 14000, 15000, 16000, or 17615, etc.

[0034] Optionally, along the thickness direction X of the first wall 11, the projected area of ​​the through hole 31 is S1 mm. 2 Satisfying: 3mm 2 ≤S1≤350mm 2; and / or the breaking strength K of the insulation component 3, satisfying: 5kv / mm≤K≤150kv / mm; and / or S2 / S3 satisfying: 0.01≤S2 / S3≤0.4.

[0035] Wherein, along the thickness direction X of the first wall 11, the projected area of ​​the through hole 31 is S1mm. 2 It can be 3mm 2 4mm 2 5mm 2 8mm 2 10mm 2 20mm 2 40mm 2 50mm 2 80mm 2 100mm 2 130mm 2 150mm 2 180mm 2 200mm 2 220mm 2 260mm 2 280mm 2 300mm 2 320mm 2 330mm 2 Or 350mm 2 wait.

[0036] The breaking strength K of the insulation component 3 can be 5kV / mm, 10kV / mm, 15kV / mm, 20kV / mm, 25kV / mm, 30kV / mm, 35kV / mm, 40kV / mm, 45kV / mm, 50kV / mm, 55kV / mm, 60kV / mm, 65kV / mm, 70kV / mm, 75kV / mm, 80kV / mm, 90kV / mm, 100kV / mm, 110kV / mm, 120kV / mm, 130kV / mm, 140kV / mm, or 150kV / mm, etc.

[0037] The values ​​of S2 / S3 can be 0.01, 0.02, 0.04, 0.05, 0.06, 0.08, 0.1, 0.12, 0.14, 0.16, 0.18, 0.2, 0.22, 0.23, 0.25, 0.26, 0.27, 0.28, 0.29, 0.3, 0.32, 0.33, 0.34, 0.35, 0.36, 0.37, 0.38, 0.39, or 0.4, etc.

[0038] Preferably, 10 ≤ K × S1 × S2 / S3 ≤ 7512. The value of K × S1 × S2 / S3 can be 10, 20, 50, 100, 500, 1000, 2000, 3000, 5000, 6000, 7000, or 7512, etc. Along the thickness direction X of the first wall 11, the projected area S1 mm of the through hole 31 is... 2 Satisfying: 5mm 2 ≤S1≤300mm 2 The breaking strength K of the insulating component 3 shall satisfy: 10 kV / mm ≤ K ≤ 100 kV / mm; and / or S2 / S3 shall satisfy: 0.05 ≤ S2 / S3 ≤ 0.3. Wherein, along the thickness direction X of the first wall 11, the projected area of ​​the through hole 31 is S1 mm². 2 It can be 5mm 2 8mm 2 10mm 2 20mm 2 40mm 2 50mm 2 80mm 2 100mm 2 130mm 2 150mm 2 180mm 2 200mm 2 220mm 2 260mm 2 280mm 2 290mm 2 Or 300mm 2 wait.

[0039] The breaking strength K of the insulating component 3 can be 10kv / mm, 15kv / mm, 20kv / mm, 25kv / mm, 30kv / mm, 35kv / mm, 40kv / mm, 45kv / mm, 50kv / mm, 55kv / mm, 60kv / mm, 65kv / mm, 70kv / mm, 75kv / mm, 80kv / mm, 90kv / mm, or 100kv / mm, etc.

[0040] The values ​​of S2 / S3 can be 0.05, 0.06, 0.08, 0.1, 0.12, 0.14, 0.16, 0.18, 0.2, 0.22, 0.23, 0.25, 0.26, 0.27, 0.28, 0.29, or 0.3, etc.

[0041] Optionally, the plurality of through holes 31 include circular through holes, satisfying: 10mm 2 ≤S1≤350mm 2The circular through-hole has better strength. When the insulating component 3 is squeezed by the battery cell 2, the force on the circular through-hole is more even, thereby reducing the deformation of the insulating component 3 and reducing the risk of the through-hole 31 being blocked, thus reducing the risk of the explosion-proof valve 4 being blocked. The area of ​​the through-hole 31 cannot be too large. If the area of ​​the through-hole 31 is too large, the battery cell 2 is likely to overlap with the shell 1, which may cause a short circuit risk. The area of ​​the through-hole 31 cannot be too small either. If the area of ​​the through-hole 31 is too small, the through-hole 31 is likely to be blocked. Therefore, the projected area of ​​the through-hole 31 is limited to 10mm. 2 ~350mm 2 .

[0042] Among the multiple through holes 31, some may be circular through holes, such as one or more through holes 31 being circular through holes, while the other through holes 31 can be any other possible shape; all of the multiple through holes 31 may also be circular through holes. It should be understood that even if all the through holes 31 are circular through holes, due to limitations such as the structure or shape of the insulating component 3, some of the through holes 31 may be square holes, quasi-circular holes, or holes of other shapes, and this application is not limited to this.

[0043] Along the thickness direction X of the first wall 11, the projected area of ​​the through hole 31 is S1mm. 2 It can be 10mm 2 20mm 2 40mm 2 50mm 2 80mm 2 100mm 2 130mm 2 150mm 2 180mm 2 200mm 2 220mm 2 260mm 2 280mm 2 300mm 2 320mm 2 330mm 2 Or 350mm 2 wait.

[0044] Optionally, the multiple through holes 31 include square through holes, satisfying: 0.01≤S2 / S3≤0.3. Square through holes have better gas conduction performance, and can quickly exhaust the gas inside the battery cell 2 when thermal runaway occurs. The value of S2 / S3 cannot be too large. If the value of S2 / S3 is too large, it means that the projected area of ​​the through hole 31 is large, and the battery cell 2 is prone to overlap with the shell 1, thus causing a short circuit risk. The value of S2 / S3 cannot be too small either. If the value of S2 / S3 is too small, it means that the projected area of ​​the through hole 31 is too small, and the through hole 31 is easily blocked. Therefore, the value of S2 / S3 is limited to 0.01 to 0.3. The values ​​of S2 / S3 can be 0.01, 0.02, 0.04, 0.05, 0.06, 0.08, 0.1, 0.12, 0.14, 0.16, 0.18, 0.2, 0.22, 0.23, 0.25, 0.26, 0.27, 0.28, 0.29, or 0.3, etc.

[0045] Among the multiple through holes 31, some may be square through holes, such as one through hole 31 being a square through hole or multiple through holes 31 being square through holes, while the other through holes 31 are any other possible shapes; multiple through holes 31 may also all be square through holes. It should be understood that even if all through holes 31 are square through holes, due to limitations such as the structure or shape of the insulating component 3, some through holes 31 may be round holes, oblong holes, square holes, or holes of other shapes, and this application is not limited to this.

[0046] Optionally, the multiple through holes 31 may include circular through holes and square through holes. Circular through holes have better strength; when the insulating component 3 is compressed by the battery cell 2, the force on the circular through holes is more uniform, thereby reducing the deformation of the insulating component 3 and reducing the risk of the through holes 31 becoming blocked, thus reducing the risk of the explosion-proof valve 4 becoming blocked. Square through holes have better gas conduction performance; when the battery cell 2 experiences thermal runaway, the gas inside the battery cell 2 can be quickly discharged. The inclusion of both circular and square through holes in the multiple through holes 31 gives the insulating component 3 both deformation resistance and rapid gas conduction capability. Of course, the multiple through holes 31 may also include other possible shapes. For example, due to limitations in the structure or shape of the insulating component 3, some through holes 31 may be quasi-circular or quasi-square holes, etc., and this application is not limited to this.

[0047] Optionally, there are multiple circular through holes and multiple square through holes. Along the thickness direction X of the first wall 11, the ratio of the projected area of ​​the multiple square through holes to the projected area of ​​the multiple circular through holes is 'a', satisfying: 0.2 ≤ a ≤ 5. To ensure the gas conduction performance and deformation resistance of the insulating component 3, it is necessary to control the area ratio of the square through holes to the circular through holes. If the ratio 'a' is too large, it indicates that there are too many square through holes. Along the thickness direction X of the first wall 11, the projected area of ​​the square through holes is large. Although the gas conduction performance is good, the square through holes are easily deformed under force. Too many square through holes will reduce the deformation resistance of the insulating component 3. The through holes 31 of the insulating component 3 are easily deformed and shrunken, thereby affecting the gas discharge of the battery cell 2, and thus affecting the pressure relief of the explosion-proof valve 4. If the ratio 'a' is too small, it indicates that there are too many circular through holes. Along the thickness direction X of the first wall 11, the projected area of ​​the circular through holes is large. Although the circular through holes can distribute the force evenly and improve the deformation resistance of the insulating component 3, too many circular through holes will reduce the gas conduction performance of the insulating component 3, thus affecting the pressure relief of the explosion-proof valve 4. Therefore, the ratio 'a' of the projected area of ​​multiple square through holes to the projected area of ​​multiple circular through holes needs to be controlled within 0.2 ≤ a ≤ 5.

[0048] The ratio 'a' between the projected area of ​​the multiple square through holes and the projected area of ​​the multiple circular through holes can be 0.2, 0.4, 0.6, 0.8, 1, 1.2, 1.5, 1.8, 2, 2.3, 2.6, 2.9, 3, 3.2, 3.5, 3.7, 3.8, 4, 4.2, 4.4, 4.6, 4.8, or 5, etc.

[0049] Optionally, the insulating member 3 has a first surface 32 close to the battery cell 2, and the inner peripheral surface of the through hole 31 transitions to the first surface 32 with a rounded corner. On the side of the through hole 31 close to the battery cell 2, the rounded corner transition between the inner peripheral surface of the through hole 31 and the first surface 32 can reduce scratching of the battery cell 2 when the through hole 31 comes into contact with the battery cell 2, and when the gas inside the battery cell 2 is discharged, the rounded corner transition structure can guide the gas, thereby improving the gas conduction performance and reducing the probability of the through hole 31 being blocked by the battery cell 2.

[0050] Optionally, refer to Figure 6 The radius of the transition fillet between the inner circumferential surface of the through hole 31 and the first surface 32 is bmm, satisfying: 0.1mm ≤ bmm ≤ 2mm. Controlling the radius of the transition fillet between the inner circumferential surface of the through hole 31 and the first surface 32 within the range of 0.1mm to 2mm makes the transition fillet easier to form and provides better air conduction. If the radius of the transition fillet bmm is too large, the strength of the insulating component 3 will decrease, thereby reducing its resistance to deformation. The insulating component 3 will be more prone to deformation, causing the through hole 31 of the insulating component 3 to shrink, thus affecting the pressure relief of the explosion-proof valve 4. If the radius of the transition fillet bmm is too small, the transition fillet is difficult to process and form, and its air conduction performance is poor.

[0051] The transition fillet radius bmm can be 0.1mm, 0.2mm, 0.5mm, 0.8mm, 1mm, 1.2mm, 1.4mm, 1.6mm, 1.8mm, 1.9mm, or 2mm, etc.

[0052] Optionally, the plurality of through holes 31 include a plurality of first through holes and a plurality of second through holes. Along the thickness direction X of the first wall 11, the projections of the plurality of first through holes overlap with the explosion-proof valve 4, and the projections of the plurality of second through holes do not overlap with the explosion-proof valve 4. The projected area of ​​the first through holes is larger than the projected area of ​​the second through holes.

[0053] Along the thickness direction X of the first wall 11, multiple first through holes are arranged opposite to the explosion-proof valve 4, and multiple second through holes are not opposite to the explosion-proof valve 4. The projected area of ​​the first through holes is larger than the projected area of ​​the second through holes. That is to say, the projected area of ​​the multiple first through holes arranged opposite to the explosion-proof valve 4 is larger, which can improve the gas conduction performance, reduce the risk of the through hole 31 of the insulating component 3 being blocked when the battery cell 2 thermally runs away, and thus reduce the impact on the opening of the explosion-proof valve 4. At the same time, the second through holes with smaller projected areas are arranged at positions that are not opposite to the explosion-proof valve 4, which can ensure the gas conduction performance of the insulating component 3 while giving the insulating component 3 better support performance.

[0054] Optionally, refer to Figure 2 and Figure 3 The insulating component 3 includes a body portion 33 and a protrusion portion 34. Along the thickness direction X of the first wall 11, the protrusion portion 34 is located on the side of the body portion 33 near the battery cell 2, and the protrusion portion 34 is disposed opposite to the explosion-proof valve 4. At least a portion of the plurality of through holes 31 are located on the protrusion portion 34, satisfying: 4≤K×S1×S2 / S3≤8800.

[0055] A protrusion 34 is provided on the side of the main body 33 near the battery cell 2, and the protrusion 34 is positioned opposite to the explosion-proof valve 4. This is equivalent to increasing the distance between the battery cell 2 and the first wall 11 at the position opposite to the explosion-proof valve 4, thereby improving the venting performance of the through hole 31. This ensures that the venting channel between the explosion-proof valve 4 and the battery cell 2 meets the requirements. At the same time, it can also reduce the risk of short circuit caused by the battery cell 2 overlapping with the first wall 11. Therefore, the size of the through hole 31 can be reduced, and the upper limit of K×S1×S2 / S3 can be reduced to satisfy: 4≤K×S1×S2 / S3≤8800.

[0056] The value of K×S1×S2 / S3 can be 4, 8, 10, 20, 50, 100, 500, 1000, 2000, 3000, 5000, 6000, 7000, 8000 or 8800, etc.

[0057] Optionally, refer to Figure 2 and Figure 3The protrusion 34 includes a peripheral wall 341 and a bottom wall 342. The peripheral wall 341 is connected to the body 33 and extends toward the battery cell 2. The bottom wall 342 is located on the side of the peripheral wall 341 facing the battery cell 2.

[0058] The peripheral wall 341 is connected to the side of the main body 33 facing the cell 2, and the bottom wall 342 is connected to the side facing the cell 2. That is, the bottom wall 342 is connected to the side of the peripheral wall 341 away from the main body 33. The main body 33, the peripheral wall 341 and the bottom wall 342 form a recessed part, which reduces the weight of the insulating part 3 and increases the energy density of the battery cell. At the same time, the smaller protrusion 34 facilitates the melting of the insulating part 3 when the cell 2 experiences thermal runaway, and reduces the blockage of the explosion-proof valve 4 by the insulating part 3.

[0059] Optionally, the peripheral wall 341 is provided with a plurality of third through holes 31, which penetrate the peripheral wall 341 along its thickness direction. Providing a plurality of third through holes 31 on the peripheral wall 341 is equivalent to increasing the number of through holes 31 provided on the insulating component 3, which can further improve the air conduction performance of the insulating component 3.

[0060] Optionally, refer to Figures 1 to 3 The battery cell also includes an electrode terminal 5, which is disposed on the first wall 11. The insulating member 3 has a first clearance hole 35. Along the thickness direction X of the first wall 11, the first clearance hole 35 penetrates the insulating member 3. A portion of the electrode terminal 5 is located in the first clearance hole 35. Along the first direction Y, the minimum distance between the first clearance hole 35 and the through hole 31 is cmm, satisfying: 30mm≤cmm≤80mm. The first direction Y is perpendicular to the thickness direction X of the first wall 11. The first direction can be the length direction of the first wall 11, the width direction of the first wall 11, or other directions perpendicular to the thickness of the first wall 11.

[0061] Electrode terminal 5 is used for electrical connection between the electrode assembly located inside the housing 1 and external devices (adjacent batteries or other electrical equipment) located outside the housing 1. The battery can discharge to external devices through the output terminal (tab 22) of the cell 2 and the output terminal (electrode terminal 5 assembly). An external power source can charge the battery through electrode terminal 5 and tab 22. Electrode terminal 5 can be directly electrically connected to tab 22 of cell 2, or it can be electrically connected to tab 22 through a metal adapter. Electrode terminal 5 is made of metal materials including but not limited to copper, argon, aluminum alloy, and copper-aluminum alloy.

[0062] The connection between the electrode terminal 5 and the insulating member 3 can be that one end of the electrode terminal 5 is accommodated in the first clearance hole 35 and connected to the insulating member 3, or one end of the electrode terminal 5 passes through the first clearance hole 35 and is connected to the adapter piece, and the insulating member 3 is connected to the adapter piece.

[0063] Both the electrode terminal 5 and the explosion-proof valve 4 are located on the first wall 11, which can improve the battery packing efficiency. However, during battery use, the electrode terminal 5 generates heat, and as a heat source, it will affect the insulating component 3, making the insulating component 3 prone to deformation. Therefore, it is necessary to control the distance between the first clearance hole 35 and the through hole 31. If the distance between the first clearance hole 35 and the through hole 31 is too small, the electrode terminal 5, as a heat source, will cause the insulating component 3 to deform, resulting in a reduction in the size of the through hole 31 and a decrease in the gas conduction performance of the through hole 31, thereby affecting the explosion-proof valve 4 from opening. If the distance between the first clearance hole 35 and the through hole 31 is too large, the electrode terminal 5 will be biased, the current path of the electrode plate of the cell 2 will increase, resulting in an increase in the internal resistance of the battery cell and affecting fast charging.

[0064] Optionally, refer to Figures 1 to 3 The battery cell also includes an injection hole 12, which is located on the first wall 11 and extends through the first wall 11 along the thickness direction X. The insulating member 3 has a second clearance hole 36, which extends through the insulating member 3 along the thickness direction X of the first wall 11 and is positioned opposite to the injection hole 12. The ratio of the projected area of ​​the second clearance hole 36 to the projected area of ​​the injection hole 12 along the thickness direction X of the first wall 11 is e, which satisfies: 0.2≤e≤2.

[0065] If the projected area of ​​the second clearance hole 36 is too small, it will affect the injection of electrolyte, thereby reducing the injection efficiency; if the projected area of ​​the second clearance hole 36 is too large, it will reduce the strength of the insulating component 3, thereby reducing the resistance to deformation of the insulating component 3. Along the thickness direction X of the first wall 11, the ratio e of the projected area of ​​the second clearance hole 36 to the projected area of ​​the injection hole 12 can be 0.2, 0.4, 0.6, 0.8, 1, 1.2, 1.3, 1.5, 1.8, 1.9 or 2.

[0066] Optionally, refer to Figure 1 The battery cell 2 includes a battery cell body 21 and a tab 22. The tab 22 is disposed on the battery cell body 21 and is led out from one side of the battery cell body 21 facing the first wall 11. Along the thickness direction X of the first wall 11, the projection of the tab 22 does not overlap with the projection of the through hole 31.

[0067] The tab 22 is disposed on one side of the positive / negative current collector and is separately / integrated with the current collector, and is electrically connected to the current collector to conduct the current on the corresponding current collector. The tab 22 is made of a metal material with good conductivity (such as copper, aluminum, or nickel).

[0068] The lead-out end of the tab 22 and the explosion-proof valve 4 are located on the same side of the housing 1, which facilitates the assembly of the cells 2 and improves the assembly efficiency of the battery cells. At the same time, the tab 22 and the through hole 31 are staggered along the thickness direction X of the first wall 11, which can prevent the tab 22 from passing through the through hole 31, thereby reducing the contact between the tab 22 and the housing 1 and causing a short circuit between the cell 2 and the housing 1, thus reducing the probability of thermal runaway.

[0069] Optionally, refer to Figure 4 The housing 1 also includes a second wall 13, which is connected to the first wall 11. The battery cell 2 includes a battery cell body 21 and a tab 22. The tab 22 is located on the battery cell body 21 and extends from the side of the battery cell body 21 facing the second wall 13. Along the thickness direction X of the first wall 11, the distance between the battery cell body 21 and the first wall 11 is h mm, satisfying: 2 mm ≤ h mm ≤ 4 mm. By limiting the distance between the battery cell body 21 and the first wall 11 to 2 mm to 4 mm along the thickness direction X of the first wall 11, the distance between the battery cell body 21 and the first wall 11 can ensure smooth exhaust of high-pressure gas in the event of thermal runaway, thereby allowing the explosion-proof valve 4 to open in time.

[0070] Wherein, along the thickness direction X of the first wall 11, the distance hmm between the battery cell 2 body 21 and the first wall 11 can be 2mm, 2.2mm, 2.4mm, 2.6mm, 2.8mm, 3mm, 3.1mm, 3.2mm, 3.3mm, 3.5mm, 3.6mm, 3.8mm or 4mm, etc.

[0071] For example, the first wall 11 is the bottom wall 342, and the second wall 13 is the side wall connected to the first wall 11. After the battery cell 2 is manufactured, the surface of the battery cell 2 will be covered with an insulating layer. That is, an insulating layer is also provided between the battery cell 2 and the housing 1. The insulating layer can improve the insulation between the battery cell 2 and the housing 1. At this time, the projected area of ​​each through hole 31 or the sum of the projected areas of multiple through holes 31 can be increased, or the projected area of ​​each through hole 31 and the sum of the projected areas of multiple through holes 31 can be increased at the same time, thereby further improving the air conduction performance of the through hole 31.

[0072] The battery cell can be a cuboid or approximately cuboid battery, and the casing 1 can also be a cuboid or approximately cuboid structure. For example, the first wall 11 is the bottom wall 342, and the second wall 13 is any one of the four side walls. Both the first wall 11 and the second wall 13 can be cuboids or approximately cuboids. Of course, the battery cell can also be a cylindrical battery or a hexagonal prism battery, etc. When the battery cell is a cylindrical battery, the top and bottom walls 342 are discs, and the sides are cylindrical side walls. For example, the first wall 11 is the top wall, and the second wall 13 is a cylindrical side wall. When the battery cell is a hexagonal prism battery, the top and bottom walls 342 are hexagonal, and six sequentially connected side walls are provided between the top and bottom walls 342. For example, the first wall 11 is either the top wall or the bottom wall 342, and the second wall 13 can be any one of the six side walls.

[0073] Optionally, refer to Figure 5 The housing 1 also includes a third wall 14, which is arranged opposite to the first wall 11 along the thickness direction X of the first wall 11; the battery cell 2 includes a battery cell 2 body 21 and a tab 22, the tab 22 is provided on the battery cell 2 body 21 and led out from one side of the battery cell 2 body 21 facing the third wall 14, satisfying: 0.05≤S2 / S3≤0.4.

[0074] The leads of the explosion-proof valve 4 and the tab 22 are located on opposite sides of the battery cell 2, facilitating the assembly of the battery cells 2 and improving assembly efficiency. Simultaneously, the insulating component 3 can support the battery cell 2. Since the distance between the battery cell 2 and the explosion-proof valve 4 is small, to ensure the explosion-proof valve 4 can open promptly in the event of thermal runaway, the area of ​​the through-hole 31 needs to be increased, i.e., the projected area of ​​the through-hole 31 needs to be increased. Therefore, the value of S2 / S3 is limited to between 0.05 and 0.4. If the value of S2 / S3 is too small, the area of ​​the through-hole 31 is too small, and the gas from thermal runaway cannot be discharged in time, affecting the opening of the explosion-proof valve 4. If the value of S2 / S3 is too large, the area of ​​the through-hole 31 is too large, resulting in low strength of the insulating component 3, making it prone to deformation.

[0075] Optionally, the insulating member 3 includes a body portion 33 and a protrusion portion 34. Along the thickness direction X of the first wall 11, the protrusion portion 34 is disposed on the side of the body portion 33 near the battery cell 2. At least a portion of the plurality of through holes 31 is disposed on the protrusion portion 34. Along the thickness direction X of the first wall 11, at least a portion of the projection of the explosion-proof valve 4 falls within the projection of the protrusion portion 34. The ratio of the area of ​​the overlapping region of the projection of the explosion-proof valve 4 and the projection of the protrusion portion 34 to the projected area of ​​the protrusion portion 34 is f, which satisfies: 0.1≤f≤1.

[0076] The protrusion 34 is disposed opposite to the explosion-proof valve 4. The protrusion 34 can increase the strength of the insulating component 3 and better support the battery cell 2. Along the thickness direction X of the first wall 11, at least a portion of the projection of the explosion-proof valve 4 falls within the projection of the protrusion 34, and the protrusion 34 is provided with a plurality of through holes 31. That is to say, at least a portion of the explosion-proof valve 4 is disposed opposite to the through holes 31 of the protrusion 34. When the battery cell 2 experiences thermal runaway, the protrusion 34 can quickly gather the thermal runaway gas to the explosion-proof valve 4, thereby relieving pressure.

[0077] The ratio f of the overlapping area of ​​the projection of the explosion-proof valve 4 and the projection of the protrusion 34 to the projected area of ​​the protrusion 34 should not be too small. If the value of f is too small, the area directly opposite the protrusion 34 and the explosion-proof valve 4 will be too small, and the protrusion 34 will not be able to quickly gather the thermal runaway gas to the explosion-proof valve 4 for depressurization.

[0078] The value of f can be 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, or 1, etc.

[0079] The preparation of the battery cell in this application embodiment includes: (1) Preparation of positive electrode sheet. The prepared positive electrode active material, conductive agent acetylene black, and binder PVDF are mixed, and a solvent (such as N-methylpyrrolidone, NMP) is added. The mixture is stirred under vacuum until the system is homogeneous to obtain a positive electrode slurry. The positive electrode slurry is uniformly coated on both surfaces of the positive electrode current collector aluminum foil, dried at room temperature, and then transferred to an oven for further drying. After cold pressing and slitting, the positive electrode sheet is obtained. Specifically, the mass ratio of positive electrode active material: conductive agent: binder satisfies (92-98):(4-1):(4-1).

[0080] (2) Preparation of negative electrode sheet. The negative electrode active material, conductive agent acetylene black, thickener CMC, and binder SBR are mixed, and deionized water is added as solvent. The mixture is stirred under vacuum until the system is homogeneous to obtain a negative electrode slurry. The negative electrode slurry is uniformly coated on both surfaces of the negative electrode current collector copper foil, dried at room temperature, and then transferred to an oven for further drying. After cold pressing and slitting, the negative electrode sheet is obtained. Specifically, the ratio of negative electrode active material: conductive agent: thickener: binder satisfies (90~96): (4~2): (2~1): (4~1).

[0081] (3) Preparation of electrolyte. Ethyl carbonate (EC), ethyl methyl carbonate (EMC) and diethyl carbonate (DEC) were mixed in a volume ratio of 1:1:1 to obtain an organic solvent. Then, fully dried lithium salt LiPF6 was dissolved in the mixed organic solvent to prepare an electrolyte with a concentration of 1 mol / L.

[0082] (4) For the preparation of the diaphragm, polyethylene film can be selected as the diaphragm.

[0083] (5) Preparation of lithium-ion batteries: The above-mentioned positive electrode, separator, and negative electrode are stacked in sequence to form a bare battery cell; the bare cell is placed in the casing, and an insulating component is set between the cell and the first wall. The battery casing is a square shell. The battery is dried, electrolyte is injected, and after encapsulation, standing, formation, and volume adjustment, a lithium-ion battery is obtained.

[0084] The positive electrode active material can be selected from one or more lithium-containing positive electrode active materials, including lithium iron phosphate, ternary materials containing nickel, cobalt, and manganese, and lithium manganese iron phosphate; the negative electrode active material can be selected from one or more negative electrode active main materials, such as artificial graphite, natural graphite, silicon carbide, silicon oxide, and lithium titanate.

[0085] Battery insulation and burst pressure deviation were tested on the battery cells obtained according to the battery preparation method described above.

[0086] The battery insulation test method is as follows: For each embodiment and comparative example, 200 corresponding lithium-ion batteries were prepared. The ratios of the through-hole area 31 of the insulating component 3 (S1), the breaking strength (K), the sum of the through-hole areas 31 of the insulating component 3 (S2), and the area S3 of the first wall 11 of the casing 1 in the lithium-ion batteries obtained in each embodiment and comparative example are shown in Table 1 below. The lithium-ion batteries obtained in each embodiment and comparative example were discharged at a rate of 0.33C to the lower limit voltage, and then charged at a rate of 0.33C to the upper limit voltage. Among them, the battery cells of each embodiment and comparative example are the same except for the differences in the through-hole area 31 of the insulating component 3 (S1), the breaking strength (K), the sum of the through-hole areas 31 of the insulating component 3 (S2), and the area S3 of the first wall 11 of the casing 1. When the positive electrode active material is a nickel-cobalt-manganese ternary cathode, the upper limit voltage is 4.25V and the lower limit voltage is 2.5V. When the positive electrode active material is lithium iron phosphate, the upper limit voltage is 3.6V and the lower limit voltage is 2.5V.

[0087] A Fluke 17B+ digital multimeter was used to measure the voltage U between electrode terminal 5 and casing 1. For lithium iron phosphate batteries, if 2V ≤ U ≤ 3V, it is determined that cell 2 and casing 1 are not connected, and the battery insulation test is qualified; if U < 2V or U > 3V, it is determined that cell 2 and casing 1 are connected, and the insulation between cell 2 and casing 2 has failed. Similarly, for ternary lithium batteries, if 2.2V ≤ U ≤ 3.2V, it is determined that cell 2 and casing 1 are not connected, and the battery insulation test is qualified; if U < 2.2V or U > 3.2V, it is determined that cell 2 and casing 1 are connected, and the insulation between cell 2 and casing 2 has failed. The number of batteries with insulation failure was recorded as n. The percentage of batteries with insulation failure was calculated using the formula (n / 200) × 100%. If the percentage is less than or equal to 5%, the battery insulation test is qualified; otherwise, the battery insulation test is unqualified.

[0088] In this test, the active material for the positive electrode of the battery was selected from LiNi, a nickel-cobalt-manganese ternary cathode material. 0.6 Co 0.2 Mn 0.2 Taking O2 as an example, the mass ratio of positive electrode active material: conductive agent: binder meets 96:2:2; the negative electrode active material is selected from artificial graphite, and the ratio of negative electrode active material: conductive agent: thickener: binder meets 95:2:1:2.

[0089] The method for measuring the explosion pressure deviation is as follows: For each embodiment and comparative example, 10 corresponding lithium-ion batteries were prepared. The ratio of the area S1 of the through hole 31 of the insulating component 3, the breaking strength K, the sum of the areas of the through holes 31 of the insulating component 3 S2 and the area S3 of the first wall 11 of the shell 1 in the lithium-ion batteries obtained in each embodiment and comparative example is shown in Table 1 below. All other parameters are the same. The lithium-ion batteries obtained in each embodiment and comparative example were charged to the upper limit voltage at 0.33C. Then, according to the GB / T31485-2015 standard, the needle penetration test requires the use of a high-temperature resistant steel needle with a diameter of 8mm to penetrate the battery at a speed of 25±5mm per second from the direction parallel to the stacking of the positive electrode, negative electrode and separator; to cause thermal runaway of the battery, the pressure of the explosion-proof valve 4 of each lithium-ion battery was measured and recorded as K1, K2, K3, ... K10 respectively. According to the formula K=(K The average burst pressure is calculated by (1+K2+K3+···+K10) / 10. The maximum burst pressure among the 10 lithium-ion batteries is denoted as Kmax and the minimum burst pressure is denoted as Kmin. The burst pressure deviation is calculated according to formulas (1) and (2), and the maximum value in formulas (1) and (2) is taken as the maximum burst pressure deviation. If the maximum burst pressure deviation is less than or equal to 40%, the burst pressure deviation is qualified; otherwise, the burst pressure deviation is unqualified.

[0090] Burst pressure deviation = ((Kmax-K) / K)×100% Formula (1) Burst pressure deviation = ((K-Kmin) / K)×100% Formula (2) When the positive electrode active material of the battery is a nickel-cobalt-manganese ternary cathode, the upper limit voltage is 4.25V and the lower limit voltage is 2.5V. When the positive electrode active material of the battery is lithium iron phosphate, the upper limit voltage is 3.6V and the lower limit voltage is 2.5V.

[0091] In this test, the positive electrode active material of the battery was selected from LiNi, a nickel-cobalt-manganese ternary cathode material. 0.6 Co 0.2 Mn 0.2 Taking O2 as an example, the mass ratio of positive electrode active material: conductive agent: binder satisfies 96:2:2; the negative electrode active material is selected from artificial graphite, and the ratio of negative electrode active material: conductive agent: thickener: binder satisfies 95:2:1:2.

[0092] The test results are shown in Table 1 below: In this application, the projected area of ​​the through hole 31 is S1 mm along the thickness direction X of the first wall 11. 2 The maximum range is 3mm 2 ≤S1≤350mm 2 The preferred range is 5mm. 2 ≤S1≤300mm 2 The maximum range of the breaking strength K of the insulating component 3 is 5kv / mm≤K≤150kv / mm, and the preferred range is 10kv / mm≤K≤100kv / mm; the maximum range of S2 / S3 is 0.01≤S2 / S3≤0.4, and the preferred range is 0.05≤S2 / S3≤0.3; the maximum range of K×S1×S2 / S3 is 4≤K×S1×S2 / S3≤17615, and the preferred range of K×S1×S2 / S3 is 10≤K×S1×S2 / S3≤7512.

[0093] As shown in Table 1, the ratios of the through-hole area S1 of the insulating component 3 in the battery cell, the breaking strength K, and the sum of the through-hole areas S2 and S3 of the insulating component 3 to the area S3 of the first wall 11 of the casing 1 are all within the maximum range of this application. Furthermore, when the value of K×S1×S2 / S3 is within the maximum range, both the battery insulation test and the burst pressure deviation are qualified. In Example 8, even if the through-hole area S1 of the insulating component 3 is not within the maximum range of this application, the ratios of the breaking strength K, the sum of the through-hole areas S2 and S3 of the insulating component 3 to the area S3 of the first wall 11 of the casing 1, and the value of K×S1×S2 / S3 are within the maximum range, both the battery insulation test and the burst pressure deviation are still qualified. In Example 9, even if the area S1 of the through hole 31 of the insulating component 3 and the breaking strength K are not within the maximum range of the application, the values ​​of S2 / S3 and K×S1×S2 / S3 are within the maximum range, and the battery insulation test and the burst pressure deviation are also qualified.

[0094] In Comparative Example 1, even though the values ​​of S2 / S3 and K are within the maximum range of this application, the value of S1 is lower than the lower limit of the maximum range of this application, and the value of K×S1×S2 / S3 is lower than the lower limit of the maximum range of this application. Therefore, the battery insulation test is qualified, but the burst pressure deviation is unqualified. In Comparative Example 3, even though the values ​​of S2 / S3 are within the maximum range of this application, the values ​​of S1, K, and K×S1×S2 / S3 are all lower than the lower limit exceeding the maximum range of this application. Therefore, the battery insulation test is qualified, but the burst pressure deviation is unqualified. In Comparative Example 2, the value of S1 is within the maximum range of this application, and the values ​​of K, S2 / S3, and K×S1×S2 / S3 are all higher than the upper limit exceeding the maximum range of this application. Therefore, the battery insulation test is unqualified, but the burst pressure deviation is qualified. In Comparative Example 4, the values ​​of S2 / S3, S1, K, and K×S1×S2 / S3 are all higher than the upper limit of the maximum range of this application, and its battery insulation test is unqualified, but the burst pressure deviation is qualified.

[0095] Therefore, as long as the ratio of the area S1 of the through hole 31 of the insulating component 3 of the battery cell, the breaking strength K, and the sum of the areas S2 of the through hole 31 of the insulating component 3 to the area S3 of the first wall 11 of the shell 1 satisfies 4≤K×S1×S2 / S3≤17615, the gas conduction performance and insulation performance of the battery cell can be satisfied, and the battery insulation test and the explosion pressure deviation are qualified.

[0096] Secondly, embodiments of this application provide a battery pack comprising the battery cells described in any of the above embodiments.

[0097] The battery pack proposed in this application includes individual battery cells and has the same beneficial effects as individual battery cells. In the individual battery cells of this application, an insulating member 3 is disposed between the first wall 11 and the battery cell 2. The insulating member 3 has good support performance and can separate the battery cell 2 and the housing 1, reducing the risk of insulation failure due to contact between the battery cell 2 and the first wall 11 after expansion. At the same time, along the thickness direction X of the first wall 11, multiple through holes 31 on the insulating member 3 are at least partially opposite to the explosion-proof valve 4. This allows the gas discharged from the battery cell 2 to be quickly gathered to the explosion-proof valve 4 when thermal runaway occurs, so that the gas pressure around the explosion-proof valve 4 increases rapidly, facilitating the rapid opening of the explosion-proof valve 4, thereby achieving rapid pressure relief of the battery cell 2 and reducing the occurrence of more serious thermal runaway. In this application, by limiting the value of K×S1×S2 / S3, the insulating member 3 has better resistance to deformation and can reduce the blockage of the through holes 31 on the insulating member 3, thereby reducing the risk of contact between the battery cell 2 and the housing 1. If the value of K×S1×S2 / S3 is too small, it means that the size of the through hole 31 of the insulating component 3 is small. Under high temperature conditions, the through hole 31 on the insulating component 3 is easily blocked, which prevents the gas in the cell 2 from being discharged and the explosion-proof valve 4 from opening in time, thus causing more serious thermal runaway. If the value of K×S1×S2 / S3 is too large, it means that the size of the through hole 31 is large, and the cell 2 can easily pass through the through hole 31 and overlap with the shell 1, thereby increasing the risk of short circuit.

[0098] Thirdly, embodiments of this application provide an electrical device, including a single battery cell as described in any of the above embodiments or a battery pack as described in the above embodiments.

[0099] The electrical equipment proposed in this application has the beneficial effects of the battery cells and battery packs described in any of the above embodiments.

[0100] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0101] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to interchangeably. Each embodiment focuses on describing the differences from other embodiments. In particular, the system embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments.

[0102] The above description is merely an embodiment of this application and is not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

[0103] Although embodiments of this application 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 this application, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A battery cell, characterized in that, include: The shell has a first wall; The battery cell is located inside the housing; An insulating component is disposed between the first wall and the battery cell along the thickness direction of the first wall. The insulating component has a plurality of spaced-apart through holes that penetrate the insulating component along the thickness direction of the first wall. The projected area of ​​each through hole is S1 mm. 2 The sum of the projected areas of the plurality of through holes is S2mm. 2 ; An explosion-proof valve is disposed on the first wall, and along the thickness direction of the first wall, the projections of the plurality of through holes at least partially coincide with the projection of the explosion-proof valve. Wherein, along the thickness direction of the first wall, the projected area of ​​the first wall is S3mm. 2 The breaking strength of the insulating component is Kkv / mm, which satisfies: 4≤K×S1×S2 / S3≤17615.

2. The battery cell according to claim 1, characterized in that, The plurality of through holes include circular through holes, satisfying: 10mm 2 ≤S1mm 2 ≤350mm 2 .

3. The battery cell according to claim 1, characterized in that, The plurality of through holes include square through holes, satisfying: 0.01≤S2 / S3≤0.

3.

4. The battery cell according to claim 1, characterized in that, The plurality of through holes include circular through holes and square through holes.

5. The battery cell according to claim 4, characterized in that, There are multiple circular through holes and multiple square through holes. Along the thickness direction of the first wall, the ratio of the projected area of ​​the multiple square through holes to the projected area of ​​the multiple circular through holes is a, which satisfies: 0.2≤a≤5.

6. The battery cell according to claim 1, characterized in that, The insulating component has a first surface close to the battery cell, and the inner circumferential surface of the through hole transitions to the first surface with a rounded corner.

7. The battery cell according to claim 6, characterized in that, The radius of the transition fillet between the inner circumferential surface of the through hole and the first surface is bmm, satisfying: 0.1mm≤bmm≤2mm.

8. The battery cell according to claim 1, characterized in that, The plurality of through holes includes a plurality of first through holes and a plurality of second through holes. Along the thickness direction of the first wall, the projections of the plurality of first through holes overlap with the explosion-proof valve, and the projections of the plurality of second through holes do not overlap with the explosion-proof valve. The projected area of ​​the first through holes is larger than the projected area of ​​the second through holes.

9. The battery cell according to claim 1, characterized in that, The insulating component includes a body portion and a protrusion portion. Along the thickness direction of the first wall, the protrusion portion is located on the side of the body portion close to the battery cell, and the protrusion portion is disposed opposite to the explosion-proof valve. At least a portion of the plurality of through holes is located on the protrusion portion, satisfying: 4≤K×S1×S2 / S3≤8800.

10. The battery cell according to claim 9, characterized in that, The protrusion includes a peripheral wall and a bottom wall. The peripheral wall is connected to the body and extends toward the battery cell, and the bottom wall is located on the side of the peripheral wall facing the battery cell.

11. The battery cell according to claim 10, characterized in that, The peripheral wall is provided with a plurality of third through holes, which penetrate the peripheral wall along the thickness direction.

12. The battery cell according to claim 1, characterized in that, It also includes electrode terminals, which are disposed on the first wall; The insulating component has a first clearance hole. Along the thickness direction of the first wall, the first clearance hole penetrates the insulating component. A portion of the electrode terminal is located in the first clearance hole. Along a first direction, the minimum distance between the first clearance hole and the through hole is cmm, satisfying: 30mm≤cmm≤80mm. The first direction is perpendicular to the thickness direction of the first wall.

13. The battery cell according to claim 1, characterized in that, It also includes an injection hole, which is located on the first wall and extends through the first wall along its thickness direction; The insulating component has a second clearance hole. Along the thickness direction of the first wall, the second clearance hole penetrates the insulating component and is disposed opposite to the injection hole. Along the thickness direction of the first wall, the ratio of the projected area of ​​the second clearance hole to the projected area of ​​the injection hole is e, which satisfies: 0.2≤e≤2.

14. The battery cell according to claim 1, characterized in that, The battery cell includes a battery cell body and a tab. The tab is disposed on the battery cell body and extends from one side of the battery cell body toward the first wall. Along the thickness direction of the first wall, the projection of the tab does not overlap with the projection of the through hole.

15. The battery cell according to claim 1, characterized in that, The housing also includes a second wall, which is connected to the first wall; The battery cell includes a battery cell body and a tab. The tab is disposed on the battery cell body and extends from one side of the battery cell body toward the second wall. Along the thickness direction of the first wall, the distance between the battery cell body and the first wall is h mm, which satisfies: 2 mm ≤ h mm ≤ 4 mm.

16. The battery cell according to claim 1, characterized in that, The housing further includes a third wall, which is disposed opposite to the first wall along the thickness direction of the first wall; The battery cell includes a battery cell body and a tab. The tab is disposed on the battery cell body and extends from one side of the battery cell body toward the third wall, satisfying: 0.05≤S2 / S3≤0.

4.

17. The battery cell according to claim 16, characterized in that, The insulating component includes a body portion and a protrusion portion. Along the thickness direction of the first wall, the protrusion portion is located on the side of the body portion near the battery cell. At least a portion of the plurality of through holes is located on the protrusion portion. Along the thickness direction of the first wall, at least a portion of the projection of the explosion-proof valve falls within the projection of the protrusion portion. The ratio of the area of ​​the overlapping region between the projection of the explosion-proof valve and the projection of the protrusion portion to the projection area of ​​the protrusion portion is f, which satisfies: 0.1≤f≤1.

18. The battery cell according to claim 1, characterized in that, Along the thickness direction of the first wall, the projected area of ​​the through hole is S1mm. 2 Satisfying: 3mm 2 ≤S1≤350mm 2 ; and / or the breaking strength K of the insulation component satisfies: 5kv / mm≤K≤150kv / mm; and / or S2 / S3 satisfies: 0.01≤S2 / S3≤0.

4.

19. The battery cell according to claim 1, characterized in that, 10≤K×S1×S2 / S3≤7512.

20. A battery pack, characterized in that, Includes the battery cell according to any one of claims 1-19.

21. An electrical appliance, characterized in that, Includes the battery cell of any one of claims 1-19 or the battery pack of claim 20.

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