Battery cell and battery pack

Abstract

The present application relates to the technical field of batteries, and discloses a battery cell and a battery pack. The battery cell comprises: a casing, having an accommodating cavity and provided with a pole hole in a first direction; a pole, comprising a main body portion, a first pole portion surrounding the main body portion, and a second pole portion surrounding the main body portion, the main body portion passing through the pole hole, the first pole portion and the second pole portion being arranged on two opposite sides of the casing in the first direction, and the second pole portion being located in the accommodating cavity; and a sealing member, surrounding the main body portion, at least part of the sealing member being provided between the first pole portion and the casing and sealing the pole hole. An accommodating space is formed between the pole and the casing, the sealing member is arranged in the accommodating space, the volume of the accommodating space is V1, the sealing member has a separated state in which the sealing member is separated from the battery cell, and in the separated state, the volume of the sealing member is V2, satisfying: 0.6≤V2 / V1≤1.3. The present application is beneficial to ensuring the sealing performance at positions of pole holes of battery cells, improving the structural reliability of insulating sealing structures, and realizing the lightweight of the battery cells.

Description

A single battery and a battery pack

[0001] Cross-references to related applications

[0002] This application claims priority to Chinese Patent Application No. CN202410804482X, filed on June 21, 2024, entitled “A Single Cell Battery and Battery Pack”, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application belongs to the field of battery technology, specifically relating to a single cell battery and a battery pack. Background Technology

[0004] Currently, cylindrical battery terminals are usually connected to the casing by riveting. In order to improve the battery's sealing performance and the insulation of the terminal placement location, it is also necessary to seal and insulate the connection between the terminal and the casing.

[0005] With the increasing demand for battery pack range, how to reduce the weight of individual cells while ensuring battery structural performance is an important research and development topic in the industry.

[0006] Application content

[0007] In view of this, the purpose of this application is to provide a single battery cell to solve the above-mentioned technical problems; another purpose of the embodiments of this application is to provide a battery pack.

[0008] In a first aspect, this application provides a single-cell battery, comprising:

[0009] The housing has a receiving cavity, and the housing has a pole hole communicating with the receiving cavity in a first direction;

[0010] The electrode post includes a main body, a first post portion surrounding the main body, and a second post portion surrounding the main body. The main body is disposed through the electrode post hole. The first post portion and the second post portion are disposed on opposite sides of the housing in the first direction, and the second post portion is located within the receiving cavity.

[0011] A sealing element surrounding the main body portion, at least a portion of which is disposed between the first post portion and the housing and seals the pole post hole;

[0012] A first insulating member surrounds the side of the seal member away from the main body, and at least a portion of the first insulating member is disposed between the first post and the housing.

[0013] The second insulating member is disposed on the side of the housing opposite to the first column portion, the second insulating member surrounds the main body portion, and at least a portion of the second insulating member is disposed between the second column portion and the housing portion;

[0014] Wherein, a receiving space is formed between the shell, the electrode post, the first insulating member and the second insulating member, the sealing member is disposed in the receiving space, the volume of the receiving space is V1, the sealing member has a separated state that is separated from the single battery cell, and in the separated state, the volume of the sealing member is V2, satisfying: 60% ≤ V2 / V1 ≤ 130%;

[0015] Alternatively, the single battery cell may further include a riveting member disposed in the receiving cavity and located on the side of the second insulating member away from the housing. The terminal post is riveted to the housing through the riveting member. An accommodating space is formed between the housing, the terminal post, the first insulating member, the second insulating member, and the riveting member. A sealing member is disposed within the accommodating space. The volume of the accommodating space is V1. The sealing member has a separated state from the single battery cell, and in the separated state, the volume of the sealing member is V2, satisfying: 0.6≤V2 / V1≤1.3.

[0016] In one alternative embodiment, the seal has a first surface in the radial direction of the pole hole that is opposite to the main body, and the first surface and the hole wall of the pole hole have a minimum dimension T in the radial direction of the pole hole, satisfying: 0.5mm≤T≤10mm.

[0017] In one alternative embodiment, the compression ratio of the seal in the first direction is P, satisfying 10% ≤ P ≤ 66%.

[0018] In one alternative embodiment, the seal has a second surface facing the body portion, and the second surface and the body portion have a minimum dimension D in the radial direction of the pole hole, satisfying: 0mm≤D≤0.05mm.

[0019] In one optional embodiment, the seal includes a first sealing portion and a second sealing portion connected to each other in the first direction. The first sealing portion is disposed on the side of the housing opposite to the second post portion and surrounds the main body portion. The second sealing portion is disposed on the side of the first sealing portion facing the second post portion and is disposed between the hole wall of the pole post hole and the main body portion, and surrounds the main body portion.

[0020] In one alternative embodiment, the first insulating member includes a first insulating portion and a second insulating portion connected to each other, the first insulating portion surrounding the seal, the second insulating portion surrounding the side of the first insulating portion away from the seal, and at least a portion of the second insulating portion surrounding the first post portion.

[0021] In one alternative embodiment, a recessed groove is provided on the side of the housing opposite to the second post portion, the recessed groove surrounds and communicates with the pole post hole, and at least a portion of the first insulating member and at least a portion of the sealing member are embedded in the recessed groove.

[0022] In one alternative embodiment, the second insulating member has an annular surface surrounding the body portion, the minimum distance between the annular surface and the body portion in the radial direction of the pole hole being less than or equal to the minimum distance between the hole wall of the pole hole and the body portion in the radial direction.

[0023] In one optional embodiment, the single battery cell further includes:

[0024] An electrode assembly is disposed within the receiving cavity and is electrically connected to the electrode post;

[0025] A third insulating element surrounds the electrode post and is spaced between the electrode assembly and the housing.

[0026] Secondly, this application provides a battery pack including the aforementioned single battery cell.

[0027] This application has the following beneficial effects:

[0028] The single-cell battery of this application embodiment includes a casing, terminals, a seal, a first insulating member, and a second insulating member. The casing has a receiving cavity, and the casing has a terminal hole communicating with the receiving cavity in a first direction. The terminal includes a main body, a first post portion surrounding the main body, and a second post portion surrounding the main body. The main body is disposed through the terminal hole, and the first post portion and the second post portion are disposed on opposite sides of the casing in the first direction. The second post portion is located within the receiving cavity. The seal surrounds the main body, and at least a portion of the seal is disposed between the first post portion and the casing and seals the terminal hole. An accommodating space is formed between the casing, the terminal, the first insulating member, and the second insulating member. The seal is disposed within the accommodating space, and the volume of the accommodating space is V1. The seal has a separated state from the single-cell battery. In the separated state, the volume of the seal is V2, which satisfies 0.6≤V2 / V1≤1.3. Alternatively, the single cell may also include a riveting component. The terminal post is riveted to the housing via the riveting component. The housing, terminal post, first insulating component, second insulating component, and riveting component form the aforementioned accommodating space. By limiting the ratio of the volume of the sealing component to the volume of the accommodating space to between 0.6 and 1.3, on the one hand, it avoids the problem of insufficient sealing effect caused by the volume of the sealing component filling the accommodating space being too small. On the other hand, it avoids the sealing component being compressed too much in the accommodating space, causing the sealing component to excessively squeeze other structures on the single cell that need to contact the sealing component and increase the mass of the single cell. This is beneficial to ensure the sealing performance of the terminal post hole position of the single cell, improve the structural reliability of the insulation and sealing structure, and achieve the lightweighting of the single cell. Attached Figure Description

[0029] 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.

[0030] Figure 1 is a schematic diagram of the structure of a single battery cell according to an embodiment of this application;

[0031] Figure 2 is a cross-sectional structural diagram of a single cell according to an embodiment of this application;

[0032] Figure 3 is an enlarged view of the structure of part A in Figure 2;

[0033] Figure 4 is an exploded structural diagram of the seal detaching from the first column and the shell according to an embodiment of this application;

[0034] Figure 5 is a schematic diagram of the accommodating space according to an embodiment of this application;

[0035] Figure 6 is a schematic diagram of the accommodating space according to another embodiment of this application;

[0036] Reference numerals: 1-Housing; 10-Receiving cavity; 11-Electrode post hole; 12-Submerged groove; 2-Electrode post; 20-Main body; 21-First post; 22-Second post; 23-Accommodation space; 3-Sealing element; 30-First sealing part; 31-Second sealing part; 32-First surface; 33-Second surface; 4-First insulating element; 40-First insulating part; 41-Second insulating part; 5-Second insulating element; 50-Annular surface; 6-Electrode assembly; 7-Third insulating element; 8-Cover plate; 9-Riveting element; X-First direction; Y-Radial. Detailed Implementation

[0037] 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, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely represents selected embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0038] To facilitate understanding of this application, the technical solutions provided in this application will be described in detail below with reference to specific embodiments.

[0039] Battery pack energy density is one of the factors affecting battery pack range. When battery packs are used in electric vehicles, the weight of the battery pack itself also affects the weight of the vehicle, which in turn affects the range of the electric vehicle.

[0040] For individual cells within a battery pack, on the one hand, it is necessary to improve the layout of individual cells to increase the energy density of the battery pack. On the other hand, while ensuring the structural performance and capacity of the battery, how to reduce the weight of individual cells to reduce the overall weight of the battery pack, thereby extending the driving range, is an important research and development topic in the industry.

[0041] In view of this, and referring to Figures 1 to 6, embodiments of this application provide a single-cell battery designed to overcome at least one of the aforementioned technical problems.

[0042] The following embodiments use a cylindrical battery as an example. In other embodiments, a prismatic battery or similar battery may also be used, which will not be elaborated here. Furthermore, the following embodiments introduce an intersecting first direction X and a radial direction Y. The first direction X is parallel to the axial direction of the electrode post 2, and the radial direction Y is the radial direction of the electrode post hole 11. It is understood that the radial direction of the electrode post hole 11 is not unique. Based on Figures 2 to 4 of this embodiment, one radial direction Y shown in one cross-section is taken as an example.

[0043] Referring to Figures 1 to 6, a single-cell battery includes a casing 1, an electrode post 2, a sealing element 3, a first insulating element 4, and a second insulating element 5.

[0044] The housing 1 has a receiving cavity 10, and the housing 1 has a pole post hole 11 in the first direction X that communicates with the receiving cavity 10. The pole post 2 includes a main body 20, a first post portion 21 surrounding the main body 20, and a second post portion 22 surrounding the main body 20. The main body 20 passes through the pole post hole 11, and the first post portion 21 and the second post portion 22 are located on opposite sides of the housing 1 in the first direction X, with the second post portion 22 located inside the receiving cavity 10. A sealing member 3 surrounds the main body 20, and at least a portion of the sealing member 3 is located between the first post portion 21 and the housing 1 and seals the pole post hole 11.

[0045] The first insulating member 4 surrounds the side of the sealing member 3 away from the main body 20, and at least a portion of the first insulating member 4 is disposed between the first column portion 21 and the housing 1.

[0046] Specifically, referring to Figures 3 and 4, the first insulating member 4 includes a first insulating portion 40 and a second insulating portion 41 connected to each other. The first insulating portion 40 surrounds the seal 3, and the second insulating portion 41 surrounds the side of the first insulating portion 40 away from the seal 3. At least a portion of the second insulating portion 41 surrounds the first post portion 21.

[0047] In addition, in some embodiments, referring to Figures 2 to 4, the single cell also includes a second insulating member 5, which is disposed on the side of the housing 1 away from the first pillar 21, surrounds the main body 20, and at least a portion of the second insulating member 5 is disposed between the second pillar 22 and the housing 1.

[0048] The second insulating element 5, together with the first insulating element 4, forms a support for the pole post 2. At the same time, the second insulating element 5 can form an insulation between the pole post 2 and the housing 1. In addition, the second insulating element 5 can also help improve the sealing performance at the pole post hole 11.

[0049] Referring to Figures 3 and 5, a receiving space 23 is formed between the housing 1, the terminal post 2, the first insulating member 4, and the second insulating member 5. The sealing member 3 is disposed in the receiving space 23. The volume of the receiving space 23 is V1. The sealing member 3 has a separated state from the single cell. In the separated state, the volume of the sealing member 3 is V2, which satisfies: 0.6≤V2 / V1≤1.3.

[0050] Specifically, V2 / V1 can be 0.6, 0.61, 0.62, 0.63, 0.64, 0.65, 0.66, 0.67, 0.68, 0.69, 0.7, 0.71, 0.72, 0.73, 0.74, 0.75, 0.76, 0.77, 0.78, 0.79, 0.80, 0.81, 0.82, 0.83, 0.84, 0.85, 0.86, 0.87, 0.88, 0.89, 0.9, 0.91, 0.92, 0.93, 0.94, 0.95, The range of values ​​consisting of any one or any two of the following: 0.96, 0.97, 0.98, 0.99, 1, 1.01, 1.02, 1.03, 1.04, 1.05, 1.06, 1.07, 1.08, 1.09, 1.10, 1.11, 1.12, 1.13, 1.14, 1.15, 1.16, 1.17, 1.18, 1.19, 1.20, 1.21, 1.22, 1.23, 1.24, 1.25, 1.26, 1.27, 1.28, 1.29, and 1.3.

[0051] It should be noted that in this embodiment, the accommodating space 23 actually includes the radial Y-space between the main body 20 and the housing 1 within the electrode hole 11, and the radial X-space between the first post 21 and the housing 1. The separated state is the normal volume of the cell when the seal 3 is not installed. After the seal 3 is placed in the accommodating space 23, it can abut against the first insulating member 4 and the second insulating member 5.

[0052] Furthermore, regarding the measurement methods for the volume V1 of the accommodating space 23 and the volume V2 of the seal 3 in the separated state:

[0053] 1. The seal 3 can be placed separately in a measuring cup, which is pre-filled with a liquid such as alcohol. The seal 3 is then placed into the measuring cup, and the volume of liquid displaced from the measuring cup after the seal 3 is added is measured by the displacement method, or the volume of the seal 3 is obtained by calculating the rise in the liquid level in the measuring cup.

[0054] 2. In this embodiment, as shown in Figure 3, the pole 2 is in a riveted state. When the pole 2 is not riveted to the housing 1, the pole 2 can be removed from the housing 1. When the pole 2 is not riveted, the accommodating space is filled with a filler such as soft clay or glue. After the filler has cured, the cured filler is removed. The volume of the filler can be measured again using the drainage method of measuring the sealing element 3 as shown in 1. This volume is the volume of the accommodating space 23.

[0055] By limiting the ratio of the volume of the seal 3 to the volume of the accommodating space 23 to between 0.6 and 1.3, on the one hand, the problem of insufficient sealing effect caused by the seal 3 filling the accommodating space 23 with too small a volume is avoided. On the other hand, the excessive compression of the seal 3 in the accommodating space 23 is avoided, which would cause the seal 3 to excessively squeeze other structures on the single cell that need to contact the seal 3 and increase the mass of the single cell. This is beneficial to ensuring the sealing performance of the terminal hole 11 of the single cell, improving the reliability of the insulation sealing structure, and realizing the lightweighting of the single cell.

[0056] In some embodiments, referring to FIG3, the single battery cell further includes a riveting member 9, which is disposed in the receiving cavity 10 and located on the side of the second insulating member 5 away from the housing 1. The terminal post 2 is riveted to the housing 1 through the riveting member 9. Specifically, the second post portion 22 is riveted to the riveting member 9 to fix the integral terminal post. Referring to FIG3, after the sealing member 3 is placed in the receiving space 23, the second insulating member 5 is actually spaced between the sealing member 3 and the riveting member 9.

[0057] In some embodiments, referring to FIG6, the second insulating member 5 may not contact the main body 20. That is, when the sealing member 3 is assembled, a portion of the sealing member 3 can abut against the riveting member 9. Therefore, the aforementioned accommodating space 23 is formed between the housing 1, the pole post 2, the first insulating member 4, the second insulating member 5 and the riveting member 9.

[0058] In some embodiments, referring to Figures 3 and 4, the seal 3 has a first surface 32 in the radial Y direction that is away from the main body 20, and the first surface 32 and the hole wall of the pole hole 11 have a minimum dimension T in the radial Y direction, satisfying: 0.5mm≤T≤10mm.

[0059] Specifically, T can be 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, 1 .6mm, 1.7mm, 1.8mm, 1.9mm, 2mm, 2.1mm, 2.2mm, 2.3mm, 2.4mm, 2.5mm, 2.6mm, 2.7mm, 2.8m m, 2.9mm, 3mm, 3.1mm, 3.2mm, 3.3mm, 3.4mm, 3.5mm, 3.6mm, 3.7mm, 3.8mm, 3.9mm, 4mm, 4.1 mm, 4.2mm, 4.3mm, 4.4mm, 4.5mm, 4.6mm, 4.7mm, 4.8mm, 4.9mm, 5mm, 5.1mm, 5.2mm, 5.3mm, The range of values ​​consisting of any one or any two of the following: 5.4mm, 5.5mm, 5.6mm, 5.7mm, 5.8mm, 5.9mm, 6mm, 6.1mm, 6.2mm, 6.3mm, 6.4mm, 6.5mm, 6.6mm, 6.7mm, 6.8mm, 6.9mm, 7mm, 7.1mm, 7.2mm, 7.3mm, 7.4mm, 7.5mm, 7.6mm, 7.7mm, 7.8mm, 7.9mm, 8mm, 8.1mm, 8.2mm, 8.3mm, 8.4mm, 8.5mm, 8.6mm, 8.7mm, 8.8mm, 8.9mm, 9mm, 9.1mm, 9.2mm, 9.3mm, 9.4mm, 9.5mm, 9.6mm, 9.7mm, 9.8mm, 9.9mm, and 10mm.

[0060] By limiting the contact size between the seal 3 and the housing 1 in the radial Y direction to between 0.5 mm and 10 mm, on the one hand, the problem of insufficient sealing effect caused by the insufficient contact amount between the seal 3 and the housing 1 is avoided. On the other hand, the problem of the seal 3 in the radial Y direction of the terminal hole 11 being too large is avoided, which would increase the weight of the single cell and increase the cost of the seal 3, resulting in material waste. This is conducive to ensuring the sealing performance of the terminal hole 11 position of the single cell and realizing the lightweighting of the single cell.

[0061] It should be noted that in this embodiment, the outer contour of the sealing element 3 is set as a circle that is collinear with the axis of the pole hole 11 and the pole 2. Therefore, the minimum dimension T of the first surface 32 and the hole wall of the pole hole 11 in the radial Y direction is (ab) / 2, where a is the diameter of the outer contour circle of the sealing element 3 and b is the opening diameter of the pole hole 11.

[0062] In some embodiments, referring to Figures 3 and 4, the compression ratio of the seal 3 in the first direction X is P, satisfying 10% ≤ P ≤ 66%.

[0063] Specifically, in this embodiment, the sealing element 3 includes a first sealing portion 30 and a second sealing portion 31 that are interconnected in the first direction X. The first sealing portion 30 is disposed on the side of the housing 1 opposite to the second post portion 22, and surrounds the main body portion 20. The second sealing portion 31 is disposed on the side of the first sealing portion 30 facing the second post portion 22, and extends between the hole wall of the pole post hole 11 and the main body portion 20, and surrounds the main body portion 20. The first sealing portion 30 and the second sealing portion 31 can be integrally molded.

[0064] As shown in Figures 3 and 4 in this embodiment, the actual example is that the first sealing part 30 is compressed and placed between the first column part 21 and the housing 1. In Figure 3, the size of the first sealing part 30 after compression in the first direction X is e. In Figure 4, the actual size of the first sealing part 30 after it is separated from the first column part 21 and the housing 1 in the first direction X is f. Therefore, in this embodiment, the compression ratio of the sealing part 3 in the first direction X is P = [(fe) / f] × 100%.

[0065] Specifically, 1-(e / f) can be 0.1, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19, 0.2, 0.21, 0.22, 0.23, 0.24, 0.25, 0.26, 0.27, 0.28, 0.29, 0.3, 0.31, 0.32, 0.33, 0.34, 0.35, 0.36, 0.37, 0.38, The range of values ​​is defined by any one or any combination of the following: 0.39, 0.4, 0.41, 0.42, 0.43, 0.44, 0.45, 0.46, 0.47, 0.48, 0.49, 0.5, 0.51, 0.52, 0.53, 0.54, 0.55, 0.56, 0.57, 0.58, 0.59, 0.6, 0.61, 0.62, 0.66, 0.64, 0.65, and 0.66. Therefore, P takes values ​​between 10% and 66%.

[0066] It should be noted that when the value of P is less than 10%, the compressibility of the seal 3 is too low, and the compression sealing effect of the seal 3 is poor. When the value of P is greater than 66%, the expansion and contraction of the seal 3 is too large, which can easily cause installation difficulties and affect assembly efficiency. Moreover, at this time, the stability and service life of the seal 3 are low, resulting in poor safety performance.

[0067] In some embodiments, referring to FIG3, the seal 3 has a second surface 33 facing the main body 20. In this embodiment, the side surfaces of the first sealing portion 30 and the second sealing portion 31 facing the main body 20 together form the second surface 33. The second surface 33 and the main body 20 have a minimum dimension D in the radial Y direction of the pole hole 11, satisfying: 0mm≤D≤0.05mm.

[0068] Referring to Figures 3 and 4, the diameter of the main body 20 in the radial Y direction is c, and the second surface 33, i.e. the inner annular surface of the sealing member 3 surrounding the main body 20, has a diameter of d in the outline circle of the second surface 33. Therefore, the minimum dimension D of the second surface 33 and the main body 20 in the radial Y direction is d = dc.

[0069] Specifically, D can be any one or any combination of 0mm, 0.01mm, 0.02mm, 0.03mm, 0.04mm, and 0.05mm.

[0070] Understandably, when the value of D is less than 0 mm, an interference fit is formed between the terminal post 2 and the hole wall of the terminal post 11, which is not conducive to the rapid assembly of the terminal post 2. When the value of D is greater than 0.05 mm, the gap between the terminal post 2 and the hole wall of the terminal post 11 is too large, which can easily lead to a decrease in the sealing performance of the terminal post 11 and the insulation performance of the terminal post 2, thereby reducing the safety of the single cell.

[0071] In addition, in some embodiments, referring to Figures 2 and 3, a recessed groove 12 is provided on the side of the housing 1 away from the second post 22. The recessed groove 12 surrounds and communicates with the pole post hole 11. At least a portion of the first insulating member 4 and at least a portion of the sealing member 3 are embedded in the recessed groove 12.

[0072] The first insulating element 4 can be injection molded around the main body 20 and the first post 21, that is, the first insulating part 40 and the second insulating part 41 can be integrally molded. The groove 12 is conducive to the quick positioning of the first insulating element 4 and the sealing element 3. The first insulating element 4 forms support for the pole post 2 and insulation between the pole post 2 and the housing 1. At the same time, it can work with the sealing element 3 to further improve the sealing effect at the pole post hole 11.

[0073] In some embodiments, referring to Figures 4 to 6, the second insulating member 5 has an annular surface 50 surrounding the main body 20, the minimum distance of the annular surface 50 in the radial Y direction from the main body 20 being less than or equal to the minimum distance of the hole wall of the pole post hole 11 in the radial Y direction from the main body 20. The second insulating member 5 can then cover the riveting member 9, reducing the risk of the riveting member 9 contacting the housing 1 and improving the insulation effect of the second insulating member 5.

[0074] In addition, in other embodiments, the minimum distance between the annular surface 50 and the main body 20 in the radial Y direction may also be greater than the minimum distance between the hole wall of the pole hole 11 and the main body 20 in the radial Y direction.

[0075] Furthermore, in some embodiments, referring to Figures 2 to 4, the single cell also includes an electrode assembly 6, a third insulating member 7, and a cover plate 8. The electrode assembly 6 is disposed within the receiving cavity 10 and is electrically connected to the terminal post 2. The third insulating member 7 surrounds the terminal post 2 and is spaced between the electrode assembly 6 and the housing 1 to form an insulating effect between the electrode assembly 6 and the housing 1. The housing 1 has an opening on the side opposite to the terminal post hole 11 for the electrode assembly 6 to be introduced into the receiving cavity 10, and the cover plate 8 is used to seal the opening.

[0076] The following embodiments of this application provide parameter experiments to verify the technical effects of the parameter value range of this application:

[0077] Table 1 shows the volume V1 = 50 mm² of the single-cell storage space 23 used in the experiment. 3 The corresponding volume V2 of the seal 3 in the separated state is 20mm. 3 Up to 80mm 3 The results are not equal. The airtightness test method is as follows: the sealing effect is tested by introducing an inert gas, such as helium, into the cavity 10.

[0078] Table 1:

[0079] Table 2 shows that the volume V1 of the single-cell storage space 23 used in the experiment is 150 mm². 3 The corresponding volume V2 of the seal 3 in the separated state is 80mm. 3 Up to 250mm 3 The results are not equal. The airtightness test method is as follows: the sealing effect is tested by introducing an inert gas, such as helium, into the cavity 10.

[0080] Table 2:

[0081] Based on Tables 1 and 2, it can be seen that when V2 / V1 < 0.6, although the gas tightness test of the single cell at room temperature is passed, the gas tightness test after storage at low temperature is not passed. When V2 / V1 > 1.3, although the gas tightness test of the single cell at both room temperature and low temperature is passed, cracks appeared in the first insulating component 4 and the second insulating component 5 after disassembly. To a certain extent, the excessive compression of the sealing component 3 caused damage to other structures. Therefore, the overall ratio of 0.6 ≤ V2 / V1 ≤ 1.3 is beneficial to ensure the sealing performance of the terminal hole 11 of the single cell, improve the reliability of the insulation and sealing structure, and achieve the lightweighting of the single cell.

[0082] The test method in Table 3 is as follows: Individual cells are placed in the electrolyte for more than 8 hours, and the corrosion of the seal 3 is observed. Cylindrical cells with seals 3 of different parameters are tested. The sealing effect is tested by introducing an inert gas, such as helium, into the cavity 10 and by using a penetrant to permeate from the outside of the terminal hole 11 into the cavity 10. Dimensions can be measured directly with a ruler, while the compressibility P can be measured using a pressure device.

[0083] Table 3:

[0084] In both Example 20 and Comparative Example 8, the contact dimension T between the seal 3 and the housing 1 in the radial Y direction is 0.5 mm, and the compression ratio P is 10%. The test results show that the helium leak test and the penetrant test are passed. However, when the compression ratio P is less than 10%, the test results show that the helium leak test is passed, but the penetrant test is not passed. Further reducing the value of T and P, as in Comparative Example 1, also shows that the helium leak test is passed, but the penetrant test is not passed.

[0085] In both Example 32 and Comparative Example 9, the contact dimension T between the seal 3 and the housing 1 in the radial Y direction is 4 mm. When the compression ratio P is 66%, both the helium test and the penetrant test pass. However, when the compression ratio P is higher than 66%, although the test results show that both the helium test and the penetrant test pass, the actual compression ratio P of the seal 3 is too high, which reduces its stability and service life, affecting assembly efficiency. Furthermore, further increasing the T value makes the seal 3 too heavy, as in Comparative Example 10, which is not conducive to the lightweighting of the single battery cell. Therefore, further increasing the value of T and increasing the value of P may still result in passing the helium test and the penetrant test, but it is not conducive to the overall weight, sealing effect, assembly efficiency, and material cost.

[0086] Referring to Comparative Example 7, T was set to 0.3 mm and P to 2%. Although the seal was made lighter, the experimental results showed that the helium leak test and the penetrant test failed. Therefore, seal 3 could not meet the sealing requirements.

[0087] Referring to Examples 20 to 38, the seal 3 satisfies 0.5mm≤T≤10mm and 10%≤P≤66%, providing good sealing performance and ensuring lightweight. The compression ratio of the seal 3 is controlled within an optimal range to improve the stability, service life and ease of assembly of the seal 3.

[0088] Accordingly, this application provides a battery pack comprising the aforementioned individual battery cells. It is understood that the battery pack can possess all the technical features and corresponding beneficial effects of the aforementioned individual battery cells, which will not be elaborated upon here.

[0089] Finally, it should be noted that the above-described embodiments are merely specific implementations of this application, used to illustrate the technical solutions of this application, and not to limit them. The protection scope of this application is not limited thereto. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features, within the scope of the technology disclosed in this application; and these modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application. All should be covered within the protection scope of this application. Therefore, the protection scope of this application should be determined by the protection scope of the claims. Industrial applicability

[0090] The single-cell battery of this application limits the ratio of the volume of the sealing element to the volume of the accommodating space to between 0.6 and 1.3. On the one hand, this avoids the problem of insufficient sealing effect caused by the sealing element filling the accommodating space with too small a volume. On the other hand, it avoids the sealing element being compressed too much in the accommodating space, which would cause the sealing element to excessively squeeze other structures on the single-cell battery that need to contact the sealing element and increase the mass of the single-cell battery. This is beneficial to ensure the sealing performance of the terminal hole position of the single-cell battery, improve the structural reliability of the insulation and sealing structure, and achieve the lightweighting of the single-cell battery.

Claims

1. A single cell, characterized by, Comprise: A shell (1) having a containing cavity (10), and the shell (1) is opened in a first direction (X) with a pole hole (11) communicating with the containing cavity (10); A pole (2) comprising a main body part (20), a first column part (21) surrounding the main body part (20), and a second column part (22) surrounding the main body part (20), the main body part (20) is threaded in the pole hole (11), the first column part (21) and the second column part (22) are located on opposite sides of the shell (1) in the first direction (X), and the second column part (22) is located in the containing cavity (10); A seal (3) surrounding the main body part (20), at least part of the seal (3) is located between the first column part (21) and the shell (1) and seals the pole hole (11); A first insulation part (4) surrounding the side of the seal (3) away from the main body part (20), and at least part of the first insulation part (4) is located between the first column part (21) and the shell (1); A second insulation part (5) located on the side of the shell (1) away from the first column part (21), the second insulation part (5) surrounds the main body part (20), and at least part of the second insulation part (5) is located between the second column part (22) and the shell (1); Wherein, the shell (1), the pole (2), the first insulation part (4) and the second insulation part (5) form a containing space (23), the seal (3) is located in the containing space (23), the volume of the containing space (23) is V1, the seal (3) has a separated state from the single battery, and in the separated state, the volume of the seal (3) is V2, satisfying: 0.6≤V2 / V1≤1.3; Or, the single battery further comprises a riveting part (9) located in the containing cavity (10), and the riveting part (9) is located on the side of the second insulation part (5) away from the shell (1), the pole (2) is riveted to the shell (1) through the riveting part (9), the shell (1), the pole (2), the first insulation part (4), the second insulation part (5) and the riveting part (9) form a containing space (23), the seal (3) is located in the containing space (23), the volume of the containing space (23) is V1, the seal (3) has a separated state from the single battery, and in the separated state, the volume of the seal (3) is V2, satisfying: 0.6≤V2 / V1≤1.

3.

2. The single battery of claim 1, wherein, The seal member (3) has a first face (32) facing away from the main body portion (20) in the radial direction (Y) of the pole column hole (11), and the first face (32) and a hole wall of the pole column hole (11) have a minimum dimension T in the radial direction (Y) of the pole column hole (11) that satisfies 0.5 mm ≤ T ≤ 10 mm.

3. The single battery according to claim 1, wherein The seal member (3) has a compression ratio P in the first direction (X) that satisfies 10% ≤ P ≤ 66%.

4. The single battery according to claim 1, wherein The seal member (3) has a second face (33) facing toward the main body portion (20), and the second face (33) and the main body portion (20) have a minimum dimension D in the radial direction (Y) of the pole column hole (11) that satisfies 0 mm ≤ D ≤ 0.05 mm.

5. The single battery according to any one of claims 1 to 4, wherein The seal member (3) includes a first seal portion (30) and a second seal portion (31) that are connected to each other in the first direction (X), the first seal portion (30) is provided on a side of the case (1) facing away from the second column portion (22), and the first seal portion (30) surrounds the main body portion (20), the second seal portion (31) is provided on a side of the first seal portion (30) facing toward the second column portion (22), the second seal portion (31) is provided between a hole wall of the pole column hole (11) and the main body portion (20), and the second seal portion (31) surrounds the main body portion (20).

6. The single battery according to claim 5, wherein The first insulating member (4) includes a first insulating portion (40) and a second insulating portion (41) that are connected to each other, the first insulating portion (40) surrounds the seal member (3), the second insulating portion (41) surrounds a side of the first insulating portion (40) facing away from the seal member (3), and at least a portion of the second insulating portion (41) surrounds the first column portion (21).

7. The single battery according to claim 6, wherein The case (1) has a sink (12) on a side facing away from the second column portion (22), the sink (12) surrounds and communicates with the pole column hole (11), and at least a portion of the first insulating member (4) and at least a portion of the seal member (3) are embedded in the sink (12).

8. The single battery according to claim 1, wherein The second insulating member (5) has a ring face (50) that surrounds the main body portion (20), and a minimum distance between the ring face (50) and the main body portion (20) in the radial direction (Y) of the pole column hole (11) is less than or equal to a minimum distance between a hole wall of the pole column hole (11) and the main body portion (20) in the radial direction (Y).

9. The single battery according to claim 1, further comprising: ​ An electrode assembly (6) is arranged in the accommodation cavity (10), and the electrode assembly (6) is electrically connected to the pole (2); A third insulation member (7) surrounds the pole (2), and the third insulation member (7) is arranged between the electrode assembly (6) and the shell (1) in a spaced manner.

10. A battery pack, characterized by, Comprise: The monomer battery according to any one of claims 1 to 9.

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