Battery cover plate assembly and single battery

Abstract

The utility model relates to the technical field of batteries, and discloses a battery cover plate assembly and a single battery, the battery cover plate assembly comprises: a metal cover plate, which is provided with a through hole; the insulating part is arranged on one side of the large surface of the metal cover plate, and an avoiding hole is formed in the position, corresponding to the through hole, of the insulating part; the insulating part extends towards one side deviating from the metal cover plate to form a plurality of convex parts, and the plurality of convex parts are arranged around the avoiding hole; the distance between two convex parts with the farthest distance in the plurality of convex parts is defined as p; and in the two convex parts with the farthest distance, the height of the convex part with the highest height raised by the insulating part is q, and p / q is more than or equal to 1 and less than or equal to 20. According to the battery cover plate assembly provided by the utility model, the convex part is arranged, so that the diaphragm close to one side of the insulating part can be supported, the diaphragm is prevented from being adsorbed to the avoiding hole or the through hole due to negative pressure, the avoiding hole or the through hole is prevented from being blocked, and the smooth operation of secondary liquid injection is ensured.

Description

Technical Field

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

[0002] The battery generally includes a cell, a shell and a cover plate, wherein the cover plate is sealed at the opening of the shell so that the shell and the cover plate enclose a receiving cavity, and the cell is arranged in the receiving cavity. The cover plate is usually provided with an injection hole to facilitate the injection of electrolyte. The preparation forms of the cell include winding type, stacking type, etc. Whether it is winding type or stacking type, a diaphragm needs to be arranged between the positive electrode sheet and the negative electrode sheet. After the cell is loaded into the receiving cavity, the edge of the diaphragm is arranged toward the cover plate.

[0003] However, during the negative pressure formation process, the negative pressure will cause the diaphragm to be adsorbed on the injection hole, blocking the injection hole and thus affecting the secondary injection of the battery. Utility Model Content

[0004] In view of this, the utility model provides a battery cover assembly and a battery to solve the problem that the diaphragm easily blocks the through hole and affects the secondary liquid injection of the battery.

[0005] In a first aspect, the utility model provides a battery cover assembly, comprising:

[0006] A metal cover plate having a through hole thereon;

[0007] An insulating member is arranged on one side of the large surface of the metal cover plate, and a avoidance hole is opened on the insulating member at a position corresponding to the through hole; the insulating member extends toward a side away from the metal cover plate to form a plurality of convex portions, and the plurality of convex portions are arranged around the avoidance hole;

[0008] The distance between the two farthest convex portions among the plurality of convex portions is defined as p; the height of the convex portion with the highest height raised by the insulating member among the two farthest convex portions is defined as q, satisfying: 1≤p / q≤20.

[0009] Beneficial effect: The battery cover plate assembly provided by the embodiment of the utility model has a plurality of protrusions extending from the side of the insulating part away from the metal cover plate, and the plurality of protrusions are arranged around the avoidance hole; by arranging the protrusions, the diaphragm close to the insulating part can be supported to prevent the diaphragm from being adsorbed on the avoidance hole or through hole due to negative pressure, and to prevent the avoidance hole or through hole from being blocked, thereby ensuring the smooth secondary injection. The relationship between p and q is further limited so that it is within a suitable range. When p becomes larger, q also needs to become higher accordingly to prevent the diaphragm in the middle of the two protrusions from partially blocking the through hole due to the large spacing between the protrusions when the diaphragm is in a negative pressure adsorption state; at the same time, in order to avoid the protrusions from interfering with the installation of the battery cell, the height of the protrusion should not be too high, and correspondingly, the distance p between the two protrusions farthest from each other among the multiple protrusions should not be too large.

[0010] In a second aspect, the utility model further provides a single cell battery, comprising:

[0011] case;

[0012] And the battery cover assembly as described above, the battery cover assembly is sealed and arranged at the opening of the shell, and the battery cover assembly and the shell are enclosed to form a receiving cavity;

[0013] A battery cell, wherein the battery cell is arranged in the accommodating cavity;

[0014] The insulating member is located between the battery cell and the battery cover assembly;

[0015] The battery cell includes a diaphragm, the porosity of the diaphragm is c, wherein the value range of c is 30%≤c≤50%, at this time, p / q satisfies: 2≤p / q≤18.

[0016] Beneficial effect: In the battery provided by the embodiment of the utility model, when the porosity c of the diaphragm is larger, the corresponding electrolyte permeability is better, but at this time the diaphragm material is relatively soft and is easily adsorbed and blocked by the through hole, so the distance p between the two farthest convex parts among the corresponding multiple convex parts should not be too large. When the porosity c of the diaphragm is smaller, the corresponding electrolyte permeability is poor, but at this time the diaphragm material is relatively hard and is not easy to block the through hole due to negative pressure adsorption, so the distance p between the two farthest convex parts among the corresponding multiple convex parts can be appropriately increased. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the specific implementation methods of the utility model or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 Schematic diagram of the battery cover assembly of the present utility model;

[0019] Figure 2 Schematic diagram of the insulating part of the present utility model;

[0020] Figure 3 Bottom view of the insulating part of the present utility model;

[0021] Figure 4 is Figure 3 Partial enlarged view of the A-A cross-section in

[0022] Figure 5 is Figure 3 Partial enlarged view of

[0023] Figure 6 Schematic diagram of the single battery of the present utility model;

[0024] Figure 7 Exploded state schematic diagram of the single battery of the present utility model;

[0025] Figure 8 Exploded state schematic diagram of another single battery of the present utility model;

[0026] Explanation of reference numerals:

[0027] 1. Battery cover assembly; 11. Metal cover; 111. Through hole; 12. Insulating part; 121. Avoidance hole; 122. Convex part;

[0028] 2. Shell; 3. Electric core; 31. Diaphragm; 32. Tab; 4. Insulating fixing layer; 5. Terminal post. Detailed implementation manners

[0029] To make the objectives, technical solutions and advantages of the embodiments of the present utility model clearer, the technical solutions in the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present utility model. Apparently, the described embodiments are some but not all of the embodiments of the present utility model. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts shall fall within the protection scope of the present utility model.

[0030] In the description of the present utility model, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be construed as a limitation to the present utility model. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0031] In the description of the present utility model, it should be noted that unless otherwise clearly specified and defined, the terms "installation", "connection", "coupling" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0032] In addition, the technical features involved in different embodiments of the present utility model described below can be combined with each other as long as they do not conflict with each other.

[0033] A battery generally includes a battery cell, a housing and a cover plate. Among them, the cover plate is hermetically arranged at the opening of the housing so that the housing and the cover plate enclose to form a receiving cavity, and the battery cell is arranged in the receiving cavity. After the battery is assembled, it is necessary to inject liquid into the interior of the receiving cavity. Usually, a liquid injection hole is opened on the cover plate so that the electrolyte can be injected into the battery through the liquid injection hole. The preparation forms of the battery cell include winding type, stacking type, etc. Whether it is winding type or stacking type, a separator needs to be arranged between the positive electrode plate and the negative electrode plate. After the battery cell is installed in the receiving cavity, the edge of the separator faces the cover plate.

[0034] During a liquid injection process, the electrolyte is injected into the receiving cavity through the liquid injection hole under the action of positive pressure. At this time, the electrolyte is likely to wash away the separator and will not affect the normal liquid injection. After the electrolyte is injected into the battery cell, a negative pressure forming process needs to be carried out. During this process, the interior of the battery housing is in a negative pressure state, and the separator is likely to be adsorbed to the liquid injection hole due to the negative pressure, blocking the liquid injection hole and affecting the secondary liquid injection of the battery.

[0035] The following combines Figures 1 to 8 , to describe the embodiments of the present utility model.

[0036] According to an embodiment of the present utility model, on the one hand, a battery cover plate assembly 1 is provided, including:

[0037] A metal cover plate 11, on which a through hole 111 is opened;

[0038] The insulating member 12 is disposed on one side of the large surface of the metal cover plate 11. The insulating member 12 is provided with an avoidance hole 121 corresponding to the position of the through hole 111; the insulating member 12 extends toward the side away from the metal cover plate 11 to form a plurality of convex portions 122, and the plurality of convex portions 122 are arranged around the avoidance hole 121;

[0039] Define the distance between the two convex portions 122 with the farthest distance among the plurality of convex portions 122 as p; among the two convex portions 122 with the farthest distance, the height of the convex portion 122 with the highest height protruding from the insulating member 12 is q, and it satisfies: 1 ≤ p / q ≤ 20.

[0040] In this embodiment, the material of the metal cover plate 11 can be aluminum, aluminum alloy, stainless steel, etc.

[0041] The metal cover plate 11 is provided with a through hole 111 so that the electrolyte can be injected into the battery interior through the through hole 111. The insulating member 12 is provided with an avoidance hole 121 corresponding to the position of the through hole 111, so as to avoid interference of the insulating member 12 with the smooth injection of the electrolyte during the liquid injection process.

[0042] The battery cover assembly 1 of this embodiment is applied to a battery. During the assembly process of the battery, first, the battery cell 3 is loaded into the housing 2, and then the battery cover assembly 1 is hermetically disposed at the opening of the housing 2. The insulating member 12 of the battery cover assembly 1 can abut against the battery cell 3 to prevent the battery cell 3 from moving in the loading direction, and at the same time, the insulating member 12 can insulate the battery cell 3 from the metal cover plate 11. Since the battery cell 3 includes a separator 31, under normal circumstances, the separator 31 will not block the through hole 111, and during a liquid injection process, the electrolyte is injected into the accommodation cavity from the through hole 111 under the action of positive pressure. At this time, the electrolyte can easily flush open the separator 31 and does not affect the normal liquid injection. After the electrolyte is injected into the battery, a negative pressure forming process needs to be carried out. During this process, the interior of the battery is in a negative pressure state, and the separator 31 on the side close to the insulating member 12 is easily adsorbed to the avoidance hole 121 or the through hole 111 due to the negative pressure, blocking the avoidance hole 121 or the through hole 111 and affecting the secondary liquid injection of the battery.

[0043] In the battery cover assembly provided by the embodiment of the present invention, a plurality of convex portions 122 are formed on the insulating member 12 extending toward the side away from the metal cover plate 11, and the plurality of convex portions 122 are arranged around the avoidance hole 121; by providing the convex portions 122, the separator 31 on the side close to the insulating member 12 can be supported, avoiding the separator 31 being adsorbed to the avoidance hole 121 or the through hole 111 due to the negative pressure, and preventing the avoidance hole 121 or the through hole 111 from being blocked, thereby ensuring the smooth progress of the secondary liquid injection.

[0044] The battery cover assembly provided by the embodiment of the present utility model further defines the relationship between p and q, making it within a suitable range. When p increases, q also needs to increase correspondingly, preventing the situation that when the diaphragm 31 is in a negative pressure adsorption state, due to the large distance between the convex portions 122, the diaphragm 31 in the middle of the two convex portions 122 still partially blocks the through hole 111; at the same time, in order to avoid interference of the convex portions 122 with the installation of the battery cell 3, the height of the convex portions 122 should not be too high. Correspondingly, the distance p between the two convex portions 122 with the farthest distance among the multiple convex portions 122 should not be too large either.

[0045] It should be noted that since the effects achieved by the diaphragm 31 blocking the avoidance hole 121 or the through hole 111 are the same, both will cause abnormalities in the injection of the electrolyte during the secondary liquid injection process. For the sake of simplicity in description, hereinafter, the diaphragm 31 blocking the avoidance hole 121 or the through hole 111 is simplified to the diaphragm 31 blocking the through hole 111, which will not mislead those skilled in the art that the diaphragm 31 cannot block the avoidance hole 121.

[0046] A pole post 5 is further provided on the metal cover plate 11.

[0047] In some embodiments, the value range of p is 6 mm ≤ p ≤ 20 mm, and the value range of q is 1 mm ≤ q ≤ 6 mm.

[0048] As an optional implementation form, the value of p can be 6 mm or 7 mm or 8 mm or 8.5 mm or 9 mm or 10 mm or 10.3 mm or 11 mm or 12 mm or 15 mm or 17 mm or 18 mm or 19 mm or 20 mm, etc.

[0049] As an optional implementation form, the value of q can be 1 mm or 1.5 mm or 2 mm or 2.8 mm or 3 mm or 4 mm or 4.5 mm or 5 mm or 5.6 mm or 6 mm, etc.

[0050] According to the embodiment of the present utility model, on the other hand, a single battery is further provided, including:

[0051] A housing 2;

[0052] And the battery cover assembly 1 as described above. The battery cover assembly 1 is sealingly disposed at the opening of the housing 2, and the battery cover assembly 1 and the housing 2 enclose a containing cavity;

[0053] A battery cell 3, the battery cell 3 is disposed in the containing cavity; the battery cell 3 includes a diaphragm 31, and the porosity of the diaphragm 31 is c, where the value range of c is 30% ≤ c ≤ 50%. At this time, p / q satisfies: 2 ≤ p / q ≤ 18.

[0054] In this embodiment, the porosity of the separator 31 is c. When the porosity c of the separator 31 is relatively large, the corresponding electrolyte has better permeability. However, at this time, the material of the separator 31 is relatively soft and is easily blocked by adsorption after blocking the through holes. Therefore, the distance p between the two farthest convex portions 122 among the corresponding plurality of convex portions 122 should not be too large. That is, in this embodiment, the upper limit of the value of p / q is 18, which is less than the maximum value of p / q, which is 20. When the porosity c of the separator 31 is relatively small, the corresponding electrolyte has poor permeability. However, at this time, the material of the separator 31 is relatively hard and is not easily blocked by negative pressure adsorption. Therefore, the distance p between the two farthest convex portions 122 among the corresponding plurality of convex portions 122 can be appropriately increased. That is, in this embodiment, the lower limit of the value of p / q is 2, which is greater than the minimum value of p / q, which is 1.

[0055] In some embodiments, the thickness of the separator 31 is d, where the value range of d is 4μm ≤ d ≤ 28μm. At this time, p / q satisfies: 2 ≤ p / q ≤ 12.5.

[0056] In this embodiment, the thickness of the separator 31 is d. The smaller the thickness d of the separator 31, the greater the deformation amount of the separator 31 under the same negative pressure condition. Then, after negative pressure formation, the separator 31 is more likely to block the through holes 111. Therefore, the distance p between the two farthest convex portions 122 among the corresponding plurality of convex portions 122 should not be too large. That is, in this embodiment, the upper limit of the value of p / q is 12.5, which is less than the maximum value of p / q, which is 20. When the thickness d of the separator 31 is larger, the deformation amount of the separator 31 under the same negative pressure condition is smaller. Then, after negative pressure formation, the separator 31 is not easily blocked by the through holes. Therefore, the distance p between the two farthest convex portions 122 among the corresponding plurality of convex portions 122 can be appropriately increased. That is, in this embodiment, the lower limit of the value of p / q is 2, which is greater than the minimum value of p / q, which is 1.

[0057] In some embodiments, in combination Figure 8 As shown, the battery cell 3 further includes: an insulating fixing layer 4, and the insulating fixing layer 4 is at least partially disposed on the side surface of the battery cell 3 close to the battery cover assembly 1;

[0058] Along the length direction of the metal cover 11, the length of the insulating fixing layer 4 is defined as L1, and the length of the battery cell 3 is defined as L2, satisfying: 0.05 ≤ L1 / L2 ≤ 0.4.

[0059] Among them, the length direction of the metal cover 11 is the direction of the longest side among the sides of the metal cover 11.

[0060] By disposing the insulating fixing layer 4 at least partially on the side of the battery cell 3 close to the battery cover assembly 1, the separator 31 can be constrained by the insulating fixing layer 4, reducing the occurrence of the separator 31 blocking the through hole 111 due to negative pressure adsorption. Since the longer the length L1 of the insulating fixing layer 4 along the length direction of the battery cell 3, the better its fixing ability, the separator 31 is less likely to block the through hole 111, while if the length L1 of the insulating fixing layer 4 along the length direction of the battery cell 3 is too short, a good fixing effect cannot be achieved. However, the length L1 of the insulating fixing layer 4 along the length direction of the battery cell 3 should not be too long to avoid the insulating fixing layer 4 having too large a covering area on the side of the battery cell 3 close to the battery cover assembly 1, which may affect the wetting effect of the electrolyte on the battery cell 3. At the same time, once the battery cell expands, the too long insulating fixing layer 4 will also damage the side of the battery cell, posing a certain safety hazard.

[0061] In some embodiments, along the length direction of the metal cover 11, the value range of the length L1 of the insulating fixing layer 4 is 20 mm ≤ L1 ≤ 40 mm. The value range of the length L2 of the battery cell 3 is 100 mm ≤ L2 ≤ 400 mm.

[0062] As an optional implementation form, the value of L1 can be 20 mm or 21 mm or 23 mm or 25 mm or 27 mm or 28 mm or 30 mm or 31 mm or 33 mm or 35 mm or 37 mm or 38 mm or 39 mm or 40 mm, etc.

[0063] As an optional implementation form, the value of L2 can be 100 mm or 115 mm or 120 mm or 180 mm or 200 mm or 230 mm or 270 mm or 300 mm or 350 mm or 400 mm, etc.

[0064] In some embodiments, as shown in Figure 7 the battery cell 3 is a wound battery cell. The battery cell 3 includes a positive electrode sheet, a negative electrode sheet, and a separator 31 separated between the positive electrode sheet and the negative electrode sheet. The battery cell 3 further includes a tab 32;

[0065] The leading end of the tab 32 is on the same side of the battery as the battery cover assembly 1. The shortest distance between the separator 31 on the side of the battery cell 3 close to the battery cover assembly 1 and the convex portion 122 is h, where the value range of h is 0 mm ≤ h ≤ 5 mm. At this time, p / q satisfies: 2 ≤ p / q ≤ 13.

[0066] When the leading end of the tab 32 is on the same side of the single battery as the battery cover assembly 1, by limiting the shortest distance h between the separator 31 on the side of the battery cell 3 close to the battery cover assembly 1 and the convex portion 122, it can be ensured that there is an initial distance between the separator 31 and the convex portion 122, avoiding the separator 31 being easily adsorbed to the through hole 111 due to negative pressure during the subsequent formation process and blocking the through hole 111.

[0067] Additionally, the shortest distance h between the separator 31 on the side of the battery cell 3 close to the battery cover assembly 1 and the convex portion 122 can be adjusted by controlling the amount of extension of the separator 31.

[0068] In some embodiments, the battery cell 3 is a stacked battery cell, and the battery cell 3 includes a battery cell body, an insulating film, and a tab 32. The insulating film is disposed between the battery cell body and the housing 2;

[0069] The lead-out end of the tab 32 and the battery cover assembly 1 are on different sides of the single battery cell. The shortest distance between the insulating film and the convex portion 122 is m, where the value range of m is 0 mm ≤ m ≤ 4 mm. At this time, p / q satisfies: 2.2 ≤ p / q ≤ 18.

[0070] In this embodiment, the insulating film can be a mylar film coated on the outer peripheral side of the battery cell body, or the separator 31 separated between the positive electrode sheet and the negative electrode sheet, or other insulating films provided on the battery cell 3.

[0071] When the lead-out end of the tab 32 and the battery cover assembly 1 are on different sides of the single battery cell, by defining the shortest distance m between the insulating film and the convex portion 122, it can ensure that there is an initial distance between the separator 31 and the convex portion 122, and avoid that during the subsequent formation process, the separator 31 is easily adsorbed on the through hole 111 due to negative pressure, causing blockage to the through hole 111.

[0072] In some embodiments, the heights of the multiple convex portions 122 protruding from the insulating member 12 are the same.

[0073] By setting the heights of the multiple convex portions 122 protruding from the insulating member 12 to be the same, it is convenient for the molding of the insulating member 12, and on the premise of satisfying the above various relational expressions, it can ensure that each convex portion 122 has a balanced supporting effect, and can make the convex portion 122 better play the anti-blocking effect.

[0074] In some embodiments, along the extending direction of the convex portion 122, the cross-sectional area of the convex portion 122 in a plane parallel to the plane where the insulating member 12 is located gradually becomes smaller.

[0075] To facilitate the injection molding of the insulating member 12 and reduce the process difficulty.

[0076] In some embodiments, the number of the convex portions 122 is N, where 2 ≤ N ≤ 8.

[0077] By defining the lower limit of the number of the convex portions 122, it can avoid the situation that the supporting effect on the separator 31 is insufficient due to too few convex portions, and avoid the separator 31 blocking the through hole 111 and affecting the secondary liquid injection of the battery. By defining the upper limit of the number of the convex portions 122, it can avoid material waste on the basis of satisfying the supporting effect on the separator 31, and at the same time avoid that too many convex portions 122 affect the liquid injection efficiency.

[0078] In some embodiments, the avoidance hole 121 is a round hole; a plurality of convex portions 122 surround the avoidance hole 121 in a circle and are evenly distributed.

[0079] By surrounding the avoidance hole 121 with a plurality of convex portions 122 in a circle and evenly distributing them, each convex portion 122 can have an equal supporting effect on the diaphragm 31, better playing a role in preventing blockage, avoiding the diaphragm 31 from blocking the through hole 111, and affecting the secondary liquid injection of the battery.

[0080] Obviously, the above embodiments are only examples for clear illustration and are not limitations on the implementation manners. Although the embodiments of the present invention are 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 present invention, and such modifications and variations all fall within the scope defined by the present invention.

Claims

1. A battery cover assembly, characterized in that: include: A metal cover plate (11) having a through hole (111) formed thereon; An insulating member (12) is arranged on one side of the large surface of the metal cover plate (11), and a avoidance hole (121) is opened on the insulating member (12) at a position corresponding to the through hole (111); the insulating member (12) extends toward a side away from the metal cover plate (11) to form a plurality of convex portions (122), and the plurality of convex portions (122) are arranged around the avoidance hole (121); The distance between two of the convex portions (122) that are farthest apart among the plurality of convex portions (122) is defined as p; the height of the convex portion (122) that is the highest protruding from the insulating member (12) among the two convex portions (122) that are farthest apart is defined as q, satisfying: 1≤p / q≤20.

2. The battery cover assembly according to claim 1, characterized in that: The value range of p is 6mm≤p≤20mm, and the value range of q is 1mm≤q≤6mm.

3. A single cell battery, characterized in that: include: Housing (2); And the battery cover assembly (1) as described in claim 1, the battery cover assembly (1) is sealed and arranged at the opening of the shell (2), and the battery cover assembly (1) and the shell (2) are enclosed to form a receiving cavity; A battery core (3), wherein the battery core (3) is arranged in the accommodating cavity; The insulating member (12) is located between the battery cell (3) and the battery cover assembly (1); The battery cell (3) comprises a diaphragm (31), the porosity of the diaphragm (31) is c, wherein the value range of c is 30%≤c≤50%, and at this time, p / q satisfies: 2≤p / q≤18.

4. The single cell according to claim 3, characterized in that: The thickness of the diaphragm (31) is d, wherein the value range of d is 4 μm≤d≤28 μm, and at this time, p / q satisfies: 2≤p / q≤12.

5.

5. The single cell according to claim 3, characterized in that: The battery cell (3) further comprises: an insulating fixing layer (4), wherein the insulating fixing layer (4) is at least partially arranged on a side surface of the battery cell (3) close to the battery cover assembly (1); Along the length direction of the metal cover plate (11), the length of the insulating fixed layer (4) is defined as L1, and the length of the battery core (3) is defined as L2, satisfying the following: 0.05≤L1 / L2≤0.

4.

6. The single cell according to claim 3, characterized in that: The battery cell (3) is a wound battery cell, the battery cell (3) comprises a positive electrode sheet, a negative electrode sheet and the separator (31) separated between the positive electrode sheet and the negative electrode sheet, and the battery cell (3) further comprises a pole ear (32); The lead end of the pole ear (32) and the battery cover assembly (1) are located on the same side of the battery, and the shortest distance between the diaphragm (31) and the protrusion (122) on the side of the battery cell (3) close to the battery cover assembly (1) is h, where the value range of h is 0mm≤h≤5mm. At this time, p / q satisfies: 2≤p / q≤13.

7. The single cell according to claim 3, characterized in that: The battery core (3) is a laminated battery core, and the battery core (3) comprises a battery core body, an insulating film and a tab (32), wherein the insulating film is arranged between the battery core body and the shell (2); The lead-out end of the pole lug (32) and the battery cover assembly (1) are located on different sides of the battery, and the shortest distance between the insulating film and the protrusion (122) is m, where the value range of m is 0mm≤m≤4mm. At this time, p / q satisfies: 2.2≤p / q≤18.

8. The single cell according to claim 3, characterized in that: The heights at which the plurality of protrusions (122) protrude from the insulating member (12) are the same.

9. The single cell according to claim 3, characterized in that: Along the extension direction of the convex portion (122), the cross-sectional area of ​​the convex portion (122) parallel to the plane where the insulating member (12) is located gradually decreases.

10. The single cell according to claim 3, characterized in that: The number of the protrusions (122) is N, where 2≤N≤8.

11. The single cell according to any one of claims 3 to 7, characterized in that: The avoidance hole (121) is a circular hole; a plurality of protrusions (122) surround the avoidance hole (121) and are evenly distributed.

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