Cover plate assembly, single battery and battery pack

Abstract

The application discloses a cover plate assembly, a single battery and a battery pack, and belongs to the technical field of batteries. The cover plate assembly comprises a cover plate and a pole. The cover plate comprises a first body and a second body connected with each other. The first body is provided with a pole hole. The second body is provided with an explosion-proof hole for mounting an explosion-proof valve. The second body comprises a first surface and a second surface oppositely arranged along the thickness direction of the cover plate. One of the first surface and the second surface is provided with a groove, and the other is provided with a boss. The groove and the boss are arranged around the explosion-proof hole. Along the width direction of the cover plate, the first body has a maximum size W0 mm, and the second body has a maximum size W1 mm, and the following condition is met: 1.04 <= W1 / W0 <= 1.07. The application increases the size of the second body where the explosion-proof hole is located in the width direction by reasonably designing the size of the cover plate in the width direction, and sets a groove and a boss on the second body to reduce the thermal influence of laser welding on the size of the cover plate in the width direction, so that the overall width of the cover plate meets the design tolerance requirement.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of batteries, and particularly relates to a cover plate assembly, a single battery and a battery pack. BACKGROUND

[0002] Lithium ion batteries are widely used in various fields such as transportation power supply, power storage power supply, new energy storage power supply, aerospace and military industry due to their advantages of large capacity, high working voltage, strong charge retention ability and long cycle life. A battery generally comprises a pole group, an electrolyte, a cover plate, a shell, an insulating protective sheet and the like. The cover plate and the shell are fixed by welding to form a sealed space for protecting the pole group. The cover plate is usually integrated with a pole, an explosion-proof valve and a liquid injection hole. The explosion-proof valve is used for directional release of high-temperature and high-pressure gas in the battery when thermal runaway occurs due to mechanical impact, internal abnormal short circuit and the like. The explosion-proof valve is welded with the cover plate and covers the explosion-proof hole. Because the welding track of the explosion-proof valve is long, the cover plate has a problem of thermal shrinkage reduction in the width direction, resulting in uneven overall width of the cover plate, and further causing problems of laser leakage and poor welding when the cover plate is welded with the shell. SUMMARY

[0003] The application provides a cover plate assembly, a single battery and a battery pack, and aims to solve the technical problem of poor welding of the cover plate with the shell caused by uneven width of the cover plate due to the long welding track of the explosion-proof valve.

[0004] Technical scheme: The application provides a cover plate assembly, comprising:

[0005] The cover plate comprises a first body and a second body connected with each other. The first body is provided with a pole hole, and the second body is provided with an explosion-proof hole for mounting an explosion-proof valve. The second body comprises a first surface and a second surface oppositely arranged along the thickness direction of the cover plate. One of the first surface and the second surface is provided with a groove, and the other of the first surface and the second surface is provided with a boss. The groove and the boss are arranged around the explosion-proof hole.

[0006] The pole is arranged in the pole hole and connected with the first body.

[0007] The first body has a maximum size W0 mm in the width direction of the cover plate, and the second body has a maximum size W1 mm in the width direction of the cover plate, and the following condition is met: 1.04≤W1 / W0≤1.07.

[0008] In some embodiments, the second body has a first side edge and a second side edge oppositely arranged along the width direction, and the groove is arranged between the explosion-proof hole and the first side edge and between the explosion-proof hole and the second side edge, respectively.

[0009] In some embodiments, the second body has a first side edge and a second side edge oppositely arranged along the width direction, and the boss is arranged between the explosion-proof hole and the first side edge and between the explosion-proof hole and the second side edge, respectively.

[0010] In some embodiments, along the width direction, the second body has a minimum dimension W2 mm, satisfying: 1.02≤W2 / W0≤1.05.

[0011] In some embodiments, along the length direction of the cover plate, the explosion-proof hole has a maximum dimension L0 mm, and the groove and / or the boss has a maximum dimension L1 mm, satisfying: 1.2≤L1 / L0≤1.35.

[0012] In some embodiments, along the thickness direction, the depth of the groove is H1 mm, satisfying: 0.8≤H1≤1.2.

[0013] In some embodiments, along the thickness direction, the boss has a maximum dimension H2 mm, satisfying: 0.5≤H2≤1.

[0014] In some embodiments, along the width direction, the distance between the groove and the explosion-proof hole is A mm, satisfying: 1.5≤A≤3.0.

[0015] In some embodiments, the groove and the boss are formed synchronously by stamping.

[0016] Correspondingly, an embodiment of the present application provides a single battery, comprising:

[0017] A shell having a receiving cavity;

[0018] An electrode assembly located in the receiving cavity;

[0019] and the cover plate assembly described above, the cover plate assembly being connected with the shell and sealing the receiving cavity;

[0020] An explosion-proof valve penetrating the explosion-proof hole and being welded with the second body.

[0021] Correspondingly, an embodiment of the present application provides a battery pack, comprising the cover plate assembly described above, or the single battery described above.

[0022] Beneficial effects: the cover plate assembly of the embodiment of the present application includes a cover plate and a pole; the cover plate includes a first body and a second body connected together, the first body is provided with a pole hole, and the second body is provided with an explosion-proof hole for mounting an explosion-proof valve; the pole is arranged in the pole hole and connected with the first body; the second body includes a first surface and a second surface oppositely arranged along the thickness direction of the cover plate, one of the first surface and the second surface is provided with a groove, and the other of the first surface and the second surface is provided with a boss; the groove and the boss are arranged around the explosion-proof hole; wherein, along the width direction of the cover plate, the first body has a maximum size W0 mm, and the second body has a maximum size W1 mm, and the following condition is met: 1.04≤W1 / W0≤1.07. The present application increases the size of the second body where the explosion-proof hole is located in the width direction by reasonably designing the size of the cover plate in the width direction, and reduces the heat influence of laser welding on the size of the cover plate in the width direction by arranging the groove and the boss around the explosion-proof hole to achieve the heat insulation effect, so as to ensure that the overall width of the cover plate meets the design tolerance requirement.

[0023] The monomer battery of the embodiment of the present application includes a shell, an electrode assembly, a cover plate assembly and an explosion-proof valve, the shell has a containing cavity; the electrode assembly is located in the containing cavity; and the above-mentioned cover plate assembly is connected with the shell and covers and seals the containing cavity; the explosion-proof valve is arranged in the explosion-proof hole and welded with the second body. The present application increases the size of the second body where the explosion-proof hole is located in the width direction by reasonably designing the size of the cover plate in the width direction, and reduces the heat influence of laser welding on the size of the cover plate in the width direction by arranging the groove and the boss around the explosion-proof hole to achieve the heat insulation effect, so as to ensure that the overall width of the cover plate meets the design tolerance requirement, thereby avoiding the problems of laser leakage and poor welding when the cover plate is welded with the shell.

[0024] The battery pack of the embodiment of the present application includes the above-mentioned cover plate assembly or the above-mentioned monomer battery, so the battery pack can have all the technical features and beneficial effects of the above-mentioned cover plate assembly or the above-mentioned monomer battery, which will not be described here. BRIEF DESCRIPTION OF DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0026] Figure 1 is a structural schematic diagram of a monomer battery of the embodiment of the present application;

[0027] Figure 2 is an exploded view of a monomer battery of the embodiment of the present application;

[0028] Figure 3 is a structural schematic diagram of a single battery according to another embodiment of the present application;

[0029] Figure 4 is a top view of a cover plate according to an embodiment of the present application;

[0030] Figure 5 is a partial schematic diagram of a cover plate according to an embodiment of the present application;

[0031] Figure 6 is a structural schematic diagram of a cover plate according to an embodiment of the present application.

[0032] Brief Description of the Drawings: 1, cover plate; 2, pole; 3, shell; 4, explosion-proof valve; 10, first body; 11, second body; 12, first surface; 13, second surface; 14, groove; 15, boss; 30, accommodating cavity; 100, pole hole; 110, explosion-proof hole; 111, first side edge; 112, second side edge; X, thickness direction; Y, width direction; Z, length direction. DETAILED DESCRIPTION

[0033] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0034] In the description of the present application, it should be understood that the terms "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined as "first", "second" can explicitly or implicitly include one or more features. In the description of the present application, the meaning of "multiple" is two or more, at least one of which can be one, two or more, unless otherwise specifically limited. In the description of the present application, "perpendicular" means completely perpendicular to 90° or almost completely perpendicular, for example, within an angle range of 80°-100°, it is considered as perpendicular, similarly, "parallel" means completely parallel or almost completely parallel, for example, within a range of 10° of complete parallel, it is considered as parallel.

[0035] Applicants note that lithium-ion batteries are widely used in various fields such as transportation power supply, power storage power supply, new energy storage power supply, aerospace and military due to their large capacity, high operating voltage, strong charge retention ability, long cycle life and other advantages. The battery generally includes: a pole group, an electrolyte, a cover plate, a shell, an insulating protective sheet and other parts. The cover plate and the shell are fixed by welding to form a sealed space for protecting the pole group. The pole group is wrapped with a bare cell insulating sheet to protect the pole group and prevent the pole group from contacting the shell to cause internal short circuit of the cell. The cover plate usually integrates a pole, an explosion-proof valve, a liquid injection hole and other structures. The explosion-proof valve is generally integrated on the cell cover plate and mainly functions as pressure relief and exhaust. It is used for directional release of internal high temperature and high pressure gas when the cell is in thermal runaway due to mechanical impact, internal abnormal short circuit and other reasons, thereby improving the safety performance of the single battery. The cover plate has a reserved explosion-proof hole. The explosion-proof valve is welded with the cover plate after processes such as stamping, annealing, cleaning and baking. However, in the actual process of the cover plate, the cover plate width direction may have a problem of thermal shrinkage reduction after the explosion-proof valve is welded due to the long welding track of the explosion-proof valve at the position of the explosion-proof hole on the cover plate, resulting in uneven overall width of the cover plate, and further leading to problems such as laser leakage and poor welding when the cover plate and the shell are welded at the position where the cover plate width is smaller.

[0036] In view of this, the cover plate assembly of the embodiment of the present application comprises a cover plate and a pole; the cover plate comprises a first body and a second body connected together, the first body is provided with a pole hole, and the second body is provided with an explosion-proof hole for mounting an explosion-proof valve; the pole is arranged in the pole hole and connected with the first body; the second body comprises a first surface and a second surface oppositely arranged along the thickness direction of the cover plate, one of the first surface and the second surface is provided with a groove, and the other of the first surface and the second surface is provided with a boss; the groove and the boss are arranged around the explosion-proof hole; wherein, along the width direction of the cover plate, the first body has a maximum dimension W0 mm, and the second body has a maximum dimension W1 mm, and the following condition is met: 1.04≤W1 / W0≤1.07. The present application increases the size of the second body where the explosion-proof hole is located in the width direction by reasonably designing the size of the cover plate in the width direction, and reduces the heat influence of laser welding on the size of the cover plate in the width direction by arranging the groove and the boss around the explosion-proof hole to play a heat insulation effect, so as to ensure that the overall width of the cover plate meets the design tolerance requirement. The monomer battery of the embodiment of the present application comprises a shell, an electrode assembly, a cover plate assembly and an explosion-proof valve, the shell has a containing cavity; the electrode assembly is located in the containing cavity; and the above-mentioned cover plate assembly is connected with the shell and covers and seals the containing cavity; the explosion-proof valve is arranged in the explosion-proof hole and welded with the second body. The present application increases the size of the second body where the explosion-proof hole is located in the width direction by reasonably designing the size of the cover plate in the width direction, and reduces the heat influence of laser welding on the size of the cover plate in the width direction by arranging the groove and the boss around the explosion-proof hole to play a heat insulation effect, so as to ensure that the overall width of the cover plate meets the design tolerance requirement, thereby avoiding the problems of laser leakage and poor welding when the cover plate is welded with the shell.

[0037] The monomer battery, the battery pack and the power utilization device of the present application will be described in detail below with reference to the accompanying drawings. The features in the following embodiments and modes of the present application can be combined with each other without conflict.

[0038] Figure 1 is a structural schematic diagram of a monomer battery of the embodiment of the present application; Figure 2 is an exploded view of a monomer battery of the embodiment of the present application; Figure 3 is a structural schematic diagram of a monomer battery of another embodiment of the present application; Figure 4 is a top view of a cover plate 1 of the embodiment of the present application; Figure 5 is a partial schematic diagram of a cover plate 1 of the embodiment of the present application; Figure 6 is a structural schematic diagram of a cover plate 1 of the embodiment of the present application.

[0039] Reference Figures 1 to 6The embodiment of the present application provides a cover plate assembly, which comprises a cover plate 1 and a pole 2; the cover plate 1 comprises a first body 10 and a second body 11 connected with each other, the first body 10 is provided with a pole hole 100, the second body 11 is provided with an explosion-proof hole 110 for mounting an explosion-proof valve 4; the pole 2 is arranged in the pole hole 100 and connected with the first body 10; the second body 11 comprises a first surface 12 and a second surface 13 arranged oppositely along the thickness direction X of the cover plate 1, one of the first surface 12 and the second surface 13 is provided with a groove 14, and the other of the first surface 12 and the second surface 13 is provided with a boss 15; the groove 14 and the boss 15 are arranged around the explosion-proof hole 110; wherein Figure 4 , along the width direction Y of the cover plate 1, the first body 10 has a maximum size W0 mm, the second body 11 has a maximum size W1 mm, and the following condition is met: 1.04<=W1 / W0<=1.07. As shown in the figure, Figure 3 the first surface 12 is provided with the groove 14, and the second surface 13 is provided with the boss 15. It can be understood that the first body 10 is not provided with the explosion-proof hole 110, so that when the explosion-proof valve 4 is welded, the heat influence of laser welding is small, and the second body 11 is provided with the explosion-proof hole 110, so that when the explosion-proof valve 4 is welded at the position of the explosion-proof hole 110, the heat influence of laser welding on the second body 11 in the width direction Y is large. The present application increases the size of the second body 11 in the width direction Y where the explosion-proof hole 110 is located by reasonably designing the size of the cover plate 1 in the width direction Y, and reduces the heat influence of laser welding on the size of the cover plate 1 in the width direction Y by arranging the groove 14 and the boss 15 around the explosion-proof hole 110 to play a heat insulation effect, so as to ensure that the overall width of the cover plate 1 meets the design tolerance requirement, and then improve the welding yield of the cover plate 1 and the shell 3.

[0040] In Figure 3In the illustrated embodiment, the second body 11 has a first side edge 111 and a second side edge 112 oppositely arranged along the width direction Y, and the second body 11 includes a first face 12 and a second face 13 oppositely arranged along the thickness direction X of the cover plate 1, the first face 12 is provided with a groove 14, and the second face 13 is provided with a boss 15, the groove 14 and the boss 15 are respectively arranged between the explosion-proof hole 110 and the first side edge 111 and between the explosion-proof hole 110 and the second side edge 112. During the laser welding process, heat will spread around, and the arrangement of the groove 14 and the boss 15 can play a certain blocking role, reducing the heat transfer from the position of the explosion-proof hole 110 of the second body 11 to other parts, thereby reducing the range and degree of heat influence. The orthographic projection of the explosion-proof hole 110 on the first side edge 111 falls within the orthographic projection of the groove 14 and the boss 15 on the first side edge 111, and the orthographic projection of the second side edge 112 falls within the orthographic projection of the groove 14 and the boss 15 on the second side edge 112. It can be understood that the length of the groove 14 and the boss 15 in the length direction Z is longer than the length of the explosion-proof hole 110 in the length direction Z, which can provide a buffer for heat diffusion during laser welding in the length direction Z. When heat spreads around from the explosion-proof hole 110, the longer groove 14 and boss 15 can better block the heat, thereby effectively reducing the heat influence of laser welding on the whole cover plate 1. This helps to maintain the dimensional stability of the cover plate 1, ensures that the cover plate 1 assembled with the explosion-proof valve 4 can meet the design requirements in the subsequent assembly process, and ensures that the cover plate 1 can meet the design requirements in the subsequent welding with the shell 3.

[0041] In Figure 4 In the illustrated embodiment, along the width direction Y, the second body 11 has a minimum size W2 mm, which satisfies: 1.02≤W2 / W0≤1.05. It can be understood that the minimum size W2 of the second body 11 along the width direction Y is the size of the second body 11 along the width direction Y between the two ends of the explosion-proof hole 110 along the length direction Z to the two ends of the groove 14 or the boss 15 along the length direction Z. Since the second body 11 between the two ends of the explosion-proof hole 110 along the length direction Z to the two ends of the groove 14 along the length direction Z is less affected by heat than the second body 11 at the position of the explosion-proof hole 110, by reasonably designing the size W2 of the second body 11 along the width direction Y between the two ends of the explosion-proof hole 110 along the length direction Z to the two ends of the groove 14 or the boss 15 along the length direction Z, that is, the ratio of the minimum size W2 of the second body 11 in the width direction Y to the maximum size W0 of the first body 10 in the width direction Y, a buffer can be provided for heat diffusion during laser welding in the length direction Z. When heat spreads around from the explosion-proof hole 110, the longer groove 14 can better block the heat, thereby effectively reducing the heat influence of laser welding on the whole cover plate 1, and ensuring that it can meet the design requirements in the subsequent use and assembly process.

[0042] In Figure 3 In the embodiment shown, along the length direction Z of the cover plate 1, the explosion-proof hole 110 has a maximum size L0 mm, and the boss 15 has a maximum size L1 mm, satisfying: 1.2≤L1 / L0≤1.35. The boss 15 extends along the length direction Z and is arranged protruding from the explosion-proof hole 110, that is, the size L1 of the boss 15 in the length direction Z is longer than the size L0 of the explosion-proof hole 110 in the length direction Z, which provides more buffer space for the diffusion of heat when welding the explosion-proof valve 4 in the length direction Z, and the longer boss 15 can better block the heat from being transmitted to the cover plate 1, thereby effectively reducing the thermal influence of laser welding on the whole cover plate 1. The overall width of the cover plate 1 meets the design tolerance requirement, improves the welding yield of the cover plate 1 and the shell 3, and improves the production efficiency.

[0043] In other embodiments, along the length direction Z of the cover plate 1, the explosion-proof hole 110 has a maximum size L0 mm, and the groove 14 has a maximum size L1 mm, satisfying: 1.2≤L1 / L0≤1.35. The groove 14 extends along the length direction Z and is arranged protruding from the explosion-proof hole 110, that is, the size L1 of the groove 14 in the length direction Z is longer than the size L0 of the explosion-proof hole 110 in the length direction Z, which provides more buffer space for the diffusion of heat when welding the explosion-proof valve 4 in the length direction Z, and the longer groove 14 can better block the heat from being transmitted to the cover plate 1, thereby effectively reducing the thermal influence of laser welding on the whole cover plate 1. The overall width of the cover plate 1 meets the design tolerance requirement, improves the welding yield of the cover plate 1 and the shell 3, and improves the production efficiency.

[0044] In Figure 5 In the embodiment shown, along the thickness direction X, the depth of the groove 14 is H1 mm, satisfying: 0.8≤H1≤1.2. Exemplarily, the depth H1 of the groove 14 can be any one of 0.8, 0.9, 1.0, 1.1, 1.2 or a range value between any two of them. If the depth of the groove 14 is too small, the ability of the groove 14 to block heat will be weakened, which cannot effectively protect the cover plate 1 from heat, thereby causing the size of the cover plate 1 to change beyond the design tolerance, affecting the welding yield with the shell 3 subsequently. If the depth of the groove 14 is too large, the overall structural strength of the cover plate 1 will be reduced, causing the cover plate 1 to be easily deformed or damaged when subjected to external force. By limiting the depth H1 of the groove 14, the embodiment can reduce the thermal influence of laser welding on the width direction Y of the cover plate 1, ensure that the overall width of the cover plate 1 assembled with the explosion-proof valve 4 meets the design requirement, and ensure the structural strength of the cover plate 1, thereby ensuring the reliability and stability of the cover plate 1.

[0045] In Figure 5In the illustrated embodiment, along the thickness direction X, the boss 15 has a maximum dimension H2 mm, satisfying: 0.5≤H2≤1. Exemplarily, the maximum dimension H2 of the boss 15 can be any one of 0.5, 0.6, 0.7, 0.8, 0.9, 1.0 or a range value between any two of them. If the height of the boss 15 is too small, the heat blocking ability of the groove 14 will be weakened, which cannot effectively protect the cover plate 1 from heat, and thus the size change of the cover plate 1 exceeds the design tolerance, affecting the welding yield with the shell 3. If the height of the boss 15 is too large, it will increase the overall weight of the cover plate 1, affecting the energy density. By limiting the maximum dimension H2 of the boss 15, the present embodiment can reduce the heat influence of laser welding on the cover plate 1 in the width direction Y, ensure that the overall width of the cover plate 1 assembled with the explosion-proof valve 4 meets the design requirements, and ensure the energy density of the single battery, thereby ensuring the reliability and stability of the cover plate 1.

[0046] In Figure 5 In the illustrated embodiment, along the width direction Y, the distance between the groove 14 and the explosion-proof hole 110 is A mm, satisfying: 1.5≤A≤3.0. Exemplarily, the distance A between the groove 14 and the explosion-proof hole 110 along the width direction Y can be any one of 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0 or a range value between any two of them. If the distance between the groove 14 and the explosion-proof hole 110 is too small, when the explosion-proof valve 4 is laser welded, the generated heat is easily directly conducted to the groove 14, so that the groove 14 is also greatly affected by heat, which cannot reduce the heat shrinkage influence of laser welding on the cover plate 1. If the distance between the groove 14 and the explosion-proof hole 110 is too large, the heat insulation effect of the groove 14 is not obvious, and the heat shrinkage influence of the cover plate 1 after welding of the explosion-proof valve 4 is large. By limiting the distance A between the groove 14 and the explosion-proof hole 110 along the width direction Y, the present embodiment can ensure that there is enough distance between the groove 14 and the explosion-proof hole 110, so that the groove 14 can effectively block the heat generated by laser welding, reduce the overall heat influence on the cover plate 1, and also not reduce the heat insulation effect due to too large distance.

[0047] In some embodiments, by setting the cover plate 1 with different sizes of A, H1, H2, W1 and W2, and welding the explosion-proof valve 4 to the cover plate 1 and measuring the size of the cover plate 1 to detect whether the width of the cover plate 1 meets the design requirements. If the width of the cover plate 1 in the width direction Y is within ±0.05 mm, it is considered that the width of the cover plate 1 meets the design requirements, and the verification results are shown in Table 1.

[0048] Table 1:

[0049]

[0050]

[0051] With reference to Examples 1 to 7, when the cover plate 1 satisfies 1.04≤W1 / W0≤1.07, 1.02≤W2 / W0≤1.05, 1.5≤A≤3.0, 0.8≤H1≤1.2, and 0.5≤H2≤1, the verification result is that the cover plate 1 has a width tolerance in the width direction Y within ±0.05 mm, and the overall width of the cover plate 1 meets the design requirements. It can be understood that by increasing the size W1 of the second body 11 at the position of the explosion-proof hole 110 in the width direction Y and the size W2 of the second body 11 between the two ends of the explosion-proof hole 110 along the length direction Z to the two ends of the boss 15 or the groove 14 along the length direction Z, and reasonably designing the size of the groove 14 and the boss 15 to ensure the heat insulation effect of the groove 14 and the boss 15, the heat influence of laser welding on the size of the cover plate 1 in the width direction Y is reduced, thereby ensuring that the overall width of the cover plate 1 assembled with the explosion-proof valve 4 meets the design tolerance requirements, and thus the welding yield of the cover plate 1 and the shell 3 can be effectively improved.

[0052] With reference to Comparative Example 1, when the cover plate 1 satisfies 1.5≤A≤3.0, 0.8≤H1≤1.2, and 0.5≤H2≤1, but does not satisfy 1.04≤W1 / W0≤1.07, 1.02≤W2 / W0≤1.05, the verification result is that the values of W1 and W2 are too small, and the width of the welding position of the explosion-proof valve 4 of the finished cover plate 1 is still slightly lower than the design value. It can be understood that when the explosion-proof hole 110 is welded with the explosion-proof valve 4, the second body 11 is greatly affected by the heat of laser welding in the width direction Y, and because the values of W1 and W2 are smaller relative to W0, the size of the second body 11 in the width direction Y is insufficient, and after being affected by the welding heat when the explosion-proof valve 4 is laser welded, the size change of the second body 11 in the width direction Y causes the overall width of the second body 11 to fail to meet the design requirements, thereby affecting the welding yield of the cover plate 1 and the shell 3.

[0053] With reference to Comparative Example 2, when the cover plate 1 satisfies 1.02≤W2 / W0≤1.05, 1.5≤A≤3.0, 0.8≤H1≤1.2, and 0.5≤H2≤1, but does not satisfy 1.04≤W1 / W0≤1.07, the verification result is that the value of W1 is too small, and the width of the welding position of the explosion-proof valve 4 of the finished cover plate 1 is still slightly lower than the design value. It can be understood that when the explosion-proof hole 110 is welded with the explosion-proof valve 4, the second body 11 is greatly affected by the heat of laser welding in the width direction Y, and because the size of W1 is smaller relative to W0, the size change of the second body 11 in the width direction Y due to thermal contraction exceeds the range allowed by the design tolerance, thereby affecting the welding yield of the cover plate 1 and the shell 3.

[0054] With reference to Comparative Example 3, when the cover plate 1 satisfies 1.04≤W1 / W0≤1.07, 1.5≤A≤3.0, 0.8≤H1≤1.2, and 0.5≤H2≤1, but does not satisfy 1.02≤W2 / W0≤1.05, the verification result is that the W2 value is too large, and the cover plate 1 product anti-explosion valve 4 welding position width has a part of the upper limit problem. It can be understood that the first body 10 is not provided with the anti-explosion hole 110, and the welding of the anti-explosion valve 4 is less affected by the laser welding heat, and the size of W2 relative to W0 is too large, which will cause the size of the second body 11 in the width direction Y to exceed the reasonable range, thereby affecting the welding yield of the cover plate 1 and the shell 3.

[0055] With reference to Comparative Example 4, when the cover plate 1 satisfies 1.04≤W1 / W0≤1.07, 1.02≤W2 / W0≤1.05, 0.8≤H1≤1.2, and 0.5≤H2≤1, but does not satisfy 1.5≤A≤3.0, the verification result is that the A value is too small, the cover plate 1 product anti-explosion valve 4 position width is unstable, and there is a problem of exceeding the tolerance. It can be understood that the distance A between the groove 14 and the anti-explosion hole 110 is too small, which will cause the heat generated during laser welding of the anti-explosion valve 4 to be easily conducted directly to the groove 14, so that the groove 14 is also affected by a large heat, and the heat cannot be effectively blocked, causing the size of the second body 11 in the width direction Y to be unstable, thereby affecting the welding yield of the cover plate 1 and the shell 3.

[0056] With reference to Comparative Example 5, when the cover plate 1 satisfies 1.04≤W1 / W0≤1.07, 1.02≤W2 / W0≤1.05, 1.5≤A≤3.0, and 0.5≤H2≤1, but does not satisfy 0.8≤H1≤1.2, the verification result is that the H1 value is too small, the cover plate 1 is greatly affected by heat shrinkage after welding of the anti-explosion valve 4, and the cover plate 1 product anti-explosion valve 4 position width is unstable, and there is a problem of exceeding the tolerance. It can be understood that the depth H1 of the groove 14 is too small, which reduces the ability of the groove 14 to block heat and cannot effectively protect the second body 11 from being affected by heat. Under the action of laser welding heat, the size of the second body 11 in the width direction Y changes beyond the design tolerance, affecting the welding yield of the cover plate 1 and the shell 3.

[0057] With reference to Comparative Example 6, when the cover plate 1 satisfies 1.04≤W1 / W0≤1.07, 1.02≤W2 / W0≤1.05, 0.8≤H1≤1.2, and 0.5≤H2≤1, but does not satisfy 1.5≤A≤3.0, the verification result is that the A value is too large, the heat insulation effect of the groove 14 is not obvious, the heat shrinkage of the cover plate 1 after welding of the explosion-proof valve 4 is large, and the width of the explosion-proof valve 4 position of the finished cover plate 1 is unstable, and there is an out-of-tolerance problem. It can be understood that when the distance A between the groove 14 and the explosion-proof hole 110 is too large, the heat insulation effect of the groove 14 is poor, and the heat generated during laser welding cannot be effectively blocked, so that the size change of the cover plate 1 in the width direction Y due to heat shrinkage exceeds the tolerance range, affecting the welding yield of the cover plate 1 and the shell 3.

[0058] In Figure 4 In the embodiment shown, the number of first bodies 10 is multiple, and the multiple first bodies 10 and the second body 11 are arranged along the length direction Z of the cover plate 1, and the second body 11 is located between at least two first bodies 10. The multiple first bodies 10 are respectively provided with pole column holes 100, and the pole column 2 includes positive and negative pole columns 2, which are respectively arranged in the pole column holes 100 and connected with the first body 10.

[0059] In some embodiments, the groove 14 and the boss 15 are synchronously punched.

[0060] With reference to Figure 1 and Figure 2 , the present application provides a single battery including a shell 3, an electrode assembly, a cover plate assembly, and an explosion-proof valve 4. The shell 3 has a receiving cavity 30; the electrode assembly is located in the receiving cavity 30; and the cover plate assembly described above is connected with the shell 3 and covers and seals the receiving cavity 30; the explosion-proof valve 4 is arranged in the explosion-proof hole 110 and is welded with the second body 11. The present application reasonably designs the size of the cover plate 1 in the width direction Y, increases the size of the second body 11 where the explosion-proof hole 110 is located in the width direction Y, and reduces the thermal influence of laser welding on the size of the cover plate 1 in the width direction Y, so as to ensure that the overall width of the cover plate 1 meets the design tolerance requirement, thereby avoiding the problems of laser leakage and poor welding when the cover plate 1 is welded with the shell 3.

[0061] In some embodiments, the second body 11 has a groove 14 located on the side of the second body 11 close to the electrode assembly and surrounding the circumferential side of the explosion-proof valve 4. The second body 11 has a boss 15 located on the side of the second body 11 away from the electrode assembly and surrounding the circumferential side of the explosion-proof valve 4. During the laser welding process, heat will spread around, and the arrangement of the groove 14 and the boss 15 can play a certain blocking role, reducing the heat transfer from the position of the explosion-proof hole 110 of the second body 11 to other parts, thereby reducing the range and degree of heat affected, thereby ensuring that the overall width of the cover plate 1 meets the design tolerance requirements, and thereby the problems of laser leakage and poor welding when the cover plate 1 is welded with the shell 3 can be avoided.

[0062] Correspondingly, the application provides a battery pack, which comprises the cover plate assembly or the single battery as described above. The battery pack further comprises a box body, wherein the at least one single battery is accommodated in the interior of the box body.

[0063] In the above embodiments, the description of each embodiment has its own focus, and the parts not described in detail in a certain embodiment can be referred to the relevant description of other embodiments.

[0064] The above describes in detail the cover plate assembly, the single battery and the battery pack provided by the embodiments of the application, and the principle and implementation manner of the application are described by using specific examples. The above description of the embodiments is only used to help understand the technical solutions and the core idea of the application; those skilled in the art should understand that the technical solutions recorded in the above embodiments can be modified, or some technical features can be replaced equivalently; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the application.

Claims

1. A cover plate assembly, characterized in that, include: A cover plate includes a first body and a second body connected to each other. The first body is provided with a pole hole, and the second body is provided with an explosion-proof hole for installing an explosion-proof valve. The second body includes a first surface and a second surface disposed opposite to each other along the thickness direction of the cover plate. One of the first surface and the second surface is provided with a groove, and the other of the first surface and the second surface is provided with a boss. The groove and the boss extend along the length direction of the cover plate. A pole post, which passes through the pole post hole and is connected to the first body; Wherein, along the width direction of the cover plate, the first body has a maximum size W0 mm, and the second body has a maximum size W1 mm, satisfying: 1.04≤W1 / W0≤1.07; The second body has a first side and a second side disposed opposite to each other along the width direction, and the grooves are respectively disposed between the explosion-proof hole and the first side and between the explosion-proof hole and the second side; The second body has a first side and a second side that are disposed opposite to each other along the width direction, and the bosses are respectively disposed between the explosion-proof hole and the first side and between the explosion-proof hole and the second side; Along the width direction, the second body has a minimum dimension W2 mm, satisfying: 1.02≤W2 / W0≤1.05; Along the width direction, the distance between the groove and the explosion-proof hole is A mm, which satisfies: 1.5≤A≤3.

0.

2. The cover plate assembly according to claim 1, characterized in that, Along the length of the cover plate, the explosion-proof hole has a maximum size of L0 mm, and the groove and / or the boss has a maximum size of L1 mm, satisfying: 1.2≤L1 / L0≤1.

35.

3. The cover plate assembly according to claim 1, characterized in that, Along the thickness direction, the depth of the groove is H1 mm, satisfying: 0.8≤H1≤1.

2.

4. The cover plate assembly according to claim 1, characterized in that, Along the thickness direction, the boss has a maximum dimension H2 mm, satisfying: 0.5 ≤ H2 ≤ 1.

5. The cover plate assembly according to claim 1, characterized in that, The groove and the boss are formed by simultaneous stamping.

6. A single-cell battery, characterized in that, include: The shell has a receiving cavity; The electrode assembly is located within the receiving cavity; And a cover assembly as described in any one of claims 1 to 5, the cover assembly being connected to the housing and sealing the receiving cavity; An explosion-proof valve is provided, which is inserted through the explosion-proof hole and welded to the second body.

7. A battery pack, characterized in that, It includes the cover plate assembly as described in any one of claims 1 to 5, or it includes the single cell as described in claim 6.

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