Single battery

Abstract

The utility model discloses a single battery, and belongs to the technical field of batteries. The single battery comprises a shell, an electrode assembly and a supporting piece, the shell is provided with an accommodating cavity; the electrode assembly is contained in the containing cavity and comprises a straight section and arc sections arranged on the two opposite sides of the straight section, and the straight section is connected with the arc sections; the supporting pieces are contained in the containing cavity, the supporting pieces are distributed on the two sides of the electrode assembly and located between the arc section and the inner wall of the shell, the supporting pieces are provided with grooves, the groove walls of the grooves are of an arc-shaped structure, and the arc section is embedded in the grooves and can be attached to the groove walls. The supporting piece is arranged between the bent arc section of the electrode assembly and the shell, so that line contact between the arc section and the inner wall of the shell is changed into surface contact, uniform stress of the arc section is ensured, meanwhile, airflow impact force borne by the arc section is reduced, the arc section is prevented from being torn in the thermal runaway state of the single battery, the fire risk is reduced, and the service life of the single battery is prolonged. And the safety of the single battery in the whole life cycle is effectively improved.

Description

Technical Field

[0001] This application belongs to the field of battery technology, specifically relating to a single-cell battery. Background Technology

[0002] Lithium-ion batteries are widely used in consumer electronics, new energy vehicles, energy storage, and other fields. Currently, wound battery cells have arc-shaped areas with significant stress. These areas may evolve into weak points at the end of the cell's life cycle or during thermal runaway, affecting the cell's electrical and safety performance. Utility Model Content

[0003] Purpose of the utility model: The embodiments of this application provide a single-cell battery, which aims to overcome the technical problem of poor safety of current wound cells.

[0004] Technical solution: This application provides a single-cell battery, including:

[0005] The housing has a receiving cavity;

[0006] An electrode assembly is housed within the accommodating cavity. The electrode assembly includes a straight section and arc segments disposed on opposite sides of the straight section, and the straight section and the arc segments are connected.

[0007] A support member is housed within the accommodating cavity. The support member is distributed on both sides of the electrode assembly and is located between the arc segment and the inner wall of the housing. The support member has a groove with an arc-shaped wall. The arc segment is embedded in the groove and can fit against the groove wall.

[0008] In some embodiments, the support member has a first surface opposite to the groove wall and a second surface located on both sides of the groove wall, both the first surface and the second surface being in contact with the interior of the housing.

[0009] In some embodiments, the single battery cell further includes a spacer, which is disposed at one end of the groove and connected to the support member;

[0010] The single battery also includes an explosion-proof valve, which is disposed on one side of the housing. The spacer and the explosion-proof valve are located on the same side of the electrode assembly, and are used to separate the electrode assembly from the explosion-proof valve.

[0011] In some embodiments, the support member and the spacer member are an integral structure.

[0012] In some embodiments, the support member has a plurality of first through holes, the first through holes penetrating the groove wall and the second surface, and the diameter of the first through holes is less than or equal to 2 mm.

[0013] In some embodiments, the spacer is provided with a plurality of through holes, the through holes being connected to the groove;

[0014] The diameter of the second through hole is less than or equal to 2 mm.

[0015] In some embodiments, along the winding axis of the electrode assembly, the spacer has a height dimension a mm, satisfying 2 ≤ a ≤ 5.

[0016] In some embodiments, along the winding axis of the electrode assembly, the groove wall has a height dimension b mm, and the housing has a height dimension c mm, satisfying 5 ≤ cb ≤ 10;

[0017] And / or, along the winding axis of the electrode assembly, the height dimension of the groove wall is the same as the height dimension of the electrode assembly.

[0018] In some embodiments, there is a gap between the electrode assembly and the tank wall, the gap being less than or equal to 1 mm.

[0019] In some embodiments, the arc segment has an arc surface on the side opposite to the straight segment, the radius of the arc surface is d mm, and the depth dimension of the groove wall is e mm, satisfying 0.1≤ed≤5.

[0020] Beneficial Effects: The single-cell battery in this embodiment includes a casing, an electrode assembly, and a support member. The casing has a receiving cavity. The electrode assembly is housed within the receiving cavity and includes a straight section and arc sections disposed on opposite sides of the straight section, with the straight section and the arc sections connected. The support member is housed within the receiving cavity, distributed on both sides of the electrode assembly and located between the arc sections and the inner wall of the casing. The support member has a groove with an arc-shaped wall. The arc sections are embedded in the groove and can fit against the groove wall. By providing a support member between the curved arc sections of the electrode assembly and the casing, the line contact between the arc sections and the inner wall of the casing is changed to a surface contact, ensuring uniform force on the arc sections. Simultaneously, it reduces the airflow impact force on the arc sections, preventing tearing of the arc sections under thermal runaway conditions of the single-cell battery, reducing the risk of fire, and effectively improving the safety of the single-cell battery throughout its entire life cycle. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1This is a schematic diagram showing the positional relationship between the support member and the spacer member in a single battery cell according to an embodiment of this application;

[0023] Figure 2 This is a three-dimensional structural diagram of a single battery cell according to an embodiment of this application, showing the assembly position relationship of the electrode assembly, support member and housing;

[0024] Figure 3 This is an exploded view of the electrode assembly and one-side support member in a single cell of an embodiment of this application. The support member and the spacer member are an integral structure.

[0025] Figure 4 This is a perspective view of a single battery cell in an embodiment of this application from a top view. The casing is omitted in the figure, and the explosion-proof valve on the cover of the single battery cell is shown.

[0026] Reference numerals: 1. Housing; 2. Electrode assembly; 21. Straight section; 22. Arc section; 3. Support member; 31. Groove; 310. Groove wall; 32. First surface; 33. Second surface; 4. Spacer; 5. Explosion-proof valve; 30. First through hole; 40. Second through hole; X. Winding axis; 221. Arc surface. Detailed Implementation

[0027] 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 a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0028] In the description of this application, it should be understood that the terms "upper," "lower," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. In the description of this application, "multiple" means two or more, and "at least one" can refer to one, two, or more, unless otherwise explicitly specified. The terms "first," "second," and "third," etc., are only for the convenience of description and are used to name parts or embodiments by number, and do not imply any order of importance between the parts or embodiments.

[0029] It should also be noted that in the accompanying drawings of this application, the arrow marked with X indicates the winding axis of the electrode assembly. In the description of this application, the winding axis is introduced to more clearly define the structure and relative positional relationship of each component in the single cell.

[0030] As a preamble to the embodiments of this application, the mainstream wound-up battery cells on the market currently have only one layer of Mylar film wrapped around the electrode assembly surface as insulation between the electrode assembly and the casing. The arc-shaped areas on both sides of the electrode assembly are in near-line contact with the casing, and there is a large space between the curved parts of the electrode assembly and the casing. This exacerbates the uneven stress on the electrode sheets in the arc-shaped areas, making them relatively weak due to stress. This makes the electrode sheets in this area more prone to breakage under the impact of airflow during thermal runaway. The gas is ejected from the explosion-proof valve. In the case of thermal runaway, the electrode sheets usually carry sparks, which can easily lead to a fire and explosion of the battery cell. On the other hand, during long-term cycling of the battery cell, uneven stress on the curved parts of the electrode assembly can also lead to lithium plating at the curved parts, reducing cycle life and posing a safety risk. Simultaneously, when a battery cell experiences thermal runaway, excessive venting inside the casing may cause the internal electrode assembly to shift, blocking the explosion-proof valve and causing the battery cell to explode.

[0031] In view of this, embodiments of this application provide a single-cell battery, which aims to solve at least one of the above-mentioned technical problems.

[0032] Please see Figures 1 to 4 As shown, the single-cell battery in this embodiment includes a housing 1, an electrode assembly 2, and a support member 3. The housing 1 has a receiving cavity. The housing 1 provides external protection and isolation for the single-cell battery, and also serves to dissipate heat, prevent leakage, and provide mechanical support. It is an important component to ensure the performance and safety of the secondary battery. The electrode assembly 2 is housed in the receiving cavity and is the core component of the secondary battery. It is generally made by winding positive and negative electrode materials and an insulating layer. The electrode assembly 2 includes a straight section 21 and arc sections 22 disposed on opposite sides of the straight section 21. The straight section 21 and the arc sections 22 are connected. The support member 3 is housed in the receiving cavity and is distributed on both sides of the electrode assembly 2. It is located between the arc sections 22 and the inner wall of the housing 1. The support member 3 has a groove 31. The groove wall 310 of the groove 31 has an arc-shaped structure. The arc section 22 is embedded in the groove 31 and can fit against the groove wall 310. By setting a support member 3 between the curved arc segment 22 of the electrode assembly 2 and the housing 1, the line contact between the arc segment 22 and the inner wall of the housing 1 is changed to a surface contact, ensuring that the arc segment 22 is subjected to uniform force. At the same time, the airflow impact force on the arc segment 22 is reduced, preventing the arc segment 22 from tearing under the thermal runaway state of the single cell, reducing the risk of fire, and effectively improving the safety of the single cell throughout its entire life cycle.

[0033] Please see Figures 1 to 3As shown, in some embodiments, the support member 3 has a first surface 32 opposite to the groove wall 310 and a second surface 33 located on both sides of the groove wall 310. Both the first surface 32 and the second surface 33 are in contact with the inner wall of the housing 1. It should be understood that while the support member 3 provides contact protection and support for the arc segment 22 of the electrode assembly 2, the first surface 32 and the second surface 33 of the support member 3 can be in contact with the inner wall of the housing 1 to fill the space between the electrode assembly 2 and the housing 1. This reduces the impact of the internal airflow on the arc segment 22 under the thermal runaway state of the single cell, and at the same time prevents the support member 3 from shaking inside the housing 1, thus providing stable support for the electrode assembly 2.

[0034] Please see Figure 1 , Figure 3 and Figure 4 As shown, in some embodiments, the single battery also includes a spacer 4, which is disposed at one end of the groove 31 and connected to the support 3; the single battery also includes an explosion-proof valve 5, which is disposed on one side of the housing 1. The spacer 4 and the explosion-proof valve 5 are located on the same side of the electrode assembly 2, and are used to separate the electrode assembly 2 from the explosion-proof valve 5. It should be understood that the single battery also includes a cover plate. The housing 1 has an opening communicating with the receiving cavity. The electrode assembly 2 is assembled into the receiving cavity through the opening, and finally the opening is sealed by the cover plate. The cover plate is provided with an explosion-proof valve 5, which is used to release pressure in time when thermal runaway occurs inside the single battery to avoid explosion. By providing a spacer 4 between the electrode assembly 2 and the explosion-proof valve 5, the electrode assembly 2 is separated from the explosion-proof valve 5, preventing the electrode assembly 2 from moving and blocking the explosion-proof valve 5 during the thermal runaway venting process of the single battery.

[0035] Please see Figure 3 As shown, in some embodiments, the support member 3 and the spacer 4 are an integral structure. It should be understood that the support member 3 and the spacer 4 are generally L-shaped. This integral structure simplifies the installation process and improves assembly efficiency. In other embodiments, the support member 3 and the spacer 4 can be independent components, with a relatively simple structure and ease of manufacturing. In actual manufacturing, the support member 3 and the spacer 4 can be directly or indirectly connected, using methods such as welding, bonding, and insertion, which will not be elaborated upon here.

[0036] In some embodiments, the support member 3 and the spacer member 4 may be made of mica or oxide materials or other high-temperature resistant insulating materials. High-temperature resistant insulating materials are those that do not melt below 500°C, have good chemical and electrochemical stability, high hardness, and are not easily deformed.

[0037] Please see Figure 1 and Figure 3As shown, in some embodiments, the support member 3 has multiple first through holes 30, which penetrate the groove wall 310 and the second surface 33. The diameter of the first through holes 30 is less than or equal to 2 mm. It should be understood that by opening multiple first through holes 30 through the groove 31 on the support member 3, on the one hand, the electrolyte in the accommodating cavity can flow better around the electrode assembly 2, improving the performance of the single cell; on the other hand, the first through holes 30 provide a channel for heat dissipation, which helps to maintain the temperature stability inside the single cell; furthermore, opening the first through holes 30 reduces the weight of the support member 3, thereby reducing the overall weight of the single cell and achieving lightweighting of the single cell.

[0038] Please see Figure 1 and Figure 3 As shown, in some embodiments, the spacer 4 has multiple through holes 40, which communicate with the groove 31; the diameter of the through holes 40 is less than or equal to 2 mm. It should be understood that the through holes 40 also optimize the flow path of the electrolyte around the electrode assembly 2, ensuring that different areas of the electrode assembly 2 are fully wetted by the electrolyte. During the operation of the single cell, ions can be transported more efficiently between the spacer 4 and the groove 31 through the through holes 40, improving the charging and discharging efficiency of the battery. Simultaneously, during the use of the single cell, the pressure inside the containment cavity may change due to gas generation (such as gas generated by electrode reactions) or temperature variations. The through holes 40 help balance the pressure inside the containment cavity, making the pressure distribution inside the entire single cell more uniform and preventing deformation or damage to the battery structure due to excessive local pressure.

[0039] Please see Figure 4 As shown, in some embodiments, the spacer 4 has a height dimension a mm along the winding axis X of the electrode assembly 2, satisfying 2 ≤ a ≤ 5. Specifically, the height dimension a of the spacer 4 can be any value among 2 mm, 3 mm, 4 mm, and 5 mm, or a range between any two values. It should be understood that controlling the height dimension of the spacer 4 between 2 mm and 5 mm can provide stable structural support to separate the electrode assembly 2 from the explosion-proof valve 5. It should be noted that when the height dimension a is less than 2 mm, it may not effectively separate the electrode assembly 2 from the explosion-proof valve 5 and form a sufficient venting channel. Simultaneously, when the positive and negative electrodes of a single cell are located on the same side, a short circuit may occur due to excessive proximity. Conversely, when the height dimension a is greater than 5 mm, it may lead to wasted space inside the accommodating cavity and uneven electrolyte distribution, resulting in a decrease in the performance of the single cell.

[0040] Please see Figure 2 and Figure 3As shown, in some embodiments, along the winding axis X of the electrode assembly 2, the groove wall 310 has a height dimension b mm, and the housing 1 has a height dimension c mm, satisfying 5 ≤ cb ≤ 10; and / or, along the winding axis X of the electrode assembly 2, the height dimension of the groove wall 310 is the same as the height dimension of the electrode assembly 2. It should be understood that the height dimension of the housing 1 is greater than the height dimension of the groove wall 310, and the excess is between 5 mm and 10 mm. This provides space for the assembly of the spacer 4 and for the storage of the electrolyte. Furthermore, it facilitates heat dissipation and pressure balance within the battery, allowing heat to dissipate through the space between the groove wall 310 and the housing 1, preventing localized overheating. The same height dimension of the groove wall 310 as the electrode assembly 2 provides precise positioning and good fixation for the assembly of the electrode assembly 2, ensuring that the electrode assembly 2 does not shift and maintaining its positional stability within the housing 1.

[0041] In some embodiments, there is a gap (not shown in the figure) between the electrode assembly 2 and the groove wall 310, and the gap size is less than or equal to 1 mm. It should be understood that the gap between the electrode assembly 2 and the groove wall 310 can provide a certain space for the electrode assembly 2 to expand during charging. When the single cell is fully charged, the electrode assembly 2 expands, and the expanded electrode assembly 2 fits against the groove wall 310 of the two side supports 3 to provide certain support for the weak area of ​​the arc segment 22, so as to ensure that the force in this area is uniform and the mechanical strength of the electrode sheet is improved.

[0042] Please see Figure 1 and Figure 3 As shown, in some embodiments, the side of the arc segment 22 facing away from the straight segment 21 has an arc surface 221 with a radius of d mm and a depth of e mm for the groove wall 310, satisfying 0.1 ≤ ed ≤ 5. Specifically, ed can be any value or a range between any two values ​​from 0.1 mm, 0.6 mm, 1.1 mm, 1.6 mm, 2.1 mm, 2.6 mm, 3.1 mm, 3.6 mm, 4.1 mm, 4.6 mm, 5.1 mm, 5.6 mm, 6.1 mm, 6.6 mm, 7.1 mm, 7.6 mm, 8.1 mm, 8.6 mm, 9.1 mm, 9.6 mm, and 5 mm. It is important to understand that the depth of the tank wall 310 is greater than the radius of the arc surface 221, and the excess is between 0.1 mm and 5 mm. On the one hand, the expansion of the arc segment 22 of the electrode assembly 2 provides space to ensure that the electrode assembly 2 and the tank wall 310 are tightly fitted together, preventing the electrode assembly 2 from shaking during operation and improving the structural stability of the single cell. On the other hand, it can ensure that the electrolyte forms a stable flow layer between the arc segment 22 and the tank wall 310, providing a good ion transport environment for the electrode reaction, thereby improving the charge and discharge performance of the battery.

[0043] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0044] The present application provides a detailed description of a single-cell battery through its embodiments, and uses specific examples to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only for the purpose of helping to understand the technical solutions and core ideas of the present application. Those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A single cell, characterized by, The single battery comprises a shell (1) having a containing cavity, an electrode assembly (2) accommodated in the containing cavity, the electrode assembly (2) comprising a straight section (21) and arc sections (22) arranged on two sides opposite to the straight section (21), and the straight section (21) being connected with the arc sections (22). The single battery further comprises a support (3) accommodated in the containing cavity, the support (3) being distributed on two sides of the electrode assembly (2) and located between the arc sections (22) and inner walls of the shell (1), the support (3) having a groove (31), a groove wall (310) of the groove (31) being in an arc structure, and the arc sections (22) being embedded in the groove (31) and capable of being fitted with the groove wall (310). The support (3) has a first face (32) opposite to the groove wall (310) and a second face (33) located on two sides of the groove wall (310), and the first face (32) and the second face (33) are fitted with the inner walls of the shell (1). The single battery further comprises a spacer (4) arranged at one end of the groove (31) and connected with the support (3).

2. The cell according to claim 1, wherein The single battery further comprises an explosion-proof valve (5) arranged on one side of the shell (1), the spacer (4) and the explosion-proof valve (5) being located on the same side of the electrode assembly (2) and used for spacing the electrode assembly (2) and the explosion-proof valve (5).

3. The cell according to claim 1, wherein The support (3) and the spacer (4) are in an integrated structure. A plurality of first through holes (30) are formed in the support (3) and penetrate the groove wall (310) and the second face (33), and a diameter of the first through hole (30) is less than or equal to 2 mm.

4. The cell according to claim 3, wherein A plurality of second through holes (40) are formed in the spacer (4) and communicate with the groove (31).

5. The cell according to claim 2, wherein A diameter of the second through hole (40) is less than or equal to 2 mm.

6. The cell according to claim 3, wherein Along a winding axis (X) of the electrode assembly (2), the spacer (4) has a height dimension a mm, and 2≤a≤5 is satisfied. Along the winding axis (X) of the electrode assembly (2), the groove wall (310) has a height dimension b mm, the shell (1) has a height dimension c mm, and 5≤c-b≤10 is satisfied.

7. The cell according to claim 3, wherein Along the winding axis (X) of the electrode assembly (2), the height dimension of the groove wall (310) is the same as a height dimension of the electrode assembly (2).

8. The cell according to claim 1, wherein A gap is formed between the electrode assembly (2) and the groove wall (310), and a size of the gap is less than or equal to 1 mm. An arc face (221) is formed on a side of the arc section (22) away from the straight section (21), a radius of the arc face (221) is d mm, a depth dimension of the groove wall (310) is e mm, and 0.1≤e-d≤5 is satisfied.

9. The cell according to claim 1, wherein ​ 10. The cell according to claim 1, wherein ​

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