Cover plate assembly, battery monomer and energy storage system

Abstract

The utility model discloses a cover plate assembly, a battery cell and an energy storage system, and belongs to the technical field of batteries. The cover plate assembly is applied to the battery monomer; the cover plate assembly comprises a first plate body and a second plate body. The second plate body and the first plate body are stacked; the side wall of the first plate body protrudes out of the side wall of the second plate body and forms a welding connection part, the welding connection part is connected with the opening of the shell of the battery monomer, and the second plate body is positioned on one surface, far away from the shell, of the first plate body; the structural strength of the second plate body is larger than that of the first plate body. The second plate body with higher structural strength is stacked on the side, away from the shell, of the first plate body to enhance the structural strength of the cover plate, and meanwhile, the welding connection part is formed on the part, protruding out of the side wall of the second plate body, of the side wall of the first plate body and connected with the opening of the shell, so that the connection reliability of the cover plate assembly and the shell is improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of batteries, and particularly relates to a cover plate assembly, a battery monomer and an energy storage system. BACKGROUND

[0002] The monomer capacity of a battery is increasingly improved, and a large monomer battery monomer can directly reduce the cost of the battery per watt-hour.

[0003] However, with the increase of the monomer capacity of the battery, the size of the battery monomer is increased, and in particular, at the end of the battery, the cover plate assembly is prone to deformation. CONTENT OF THE UTILITY MODEL

[0004] The utility model aims to overcome the technical problem that the current cover plate structure strength cannot meet the demand of large-capacity batteries, and provides a cover plate assembly, a battery monomer and an energy storage system.

[0005] TECHNICAL SCHEME The utility model provides a cover plate assembly, which is applied to a battery monomer, and comprises:

[0006] A first plate body;

[0007] A second plate body is arranged in layers with the first plate body;

[0008] The side wall of the first plate body protrudes from the side wall of the second plate body and forms a welding connection part, the welding connection part is connected with an open part of a shell of the battery monomer, and the second plate body is located on a side of the first plate body away from the shell;

[0009] The structural strength of the second plate body is greater than that of the first plate body.

[0010] In some embodiments, the first plate body further comprises a main body part and a thinning part with a thickness smaller than the main body part, the thinning part is connected around the outer periphery of the main body part, and the welding connection part is connected around the thinning part.

[0011] In some embodiments, the thinning part is provided with a convex part on a side away from the second plate body, and the convex part can be accommodated in the open part of the shell.

[0012] In some embodiments, part of the thinning part is located on a side of the convex part away from the welding connection part.

[0013] In some embodiments, the elastic modulus of the second plate body is greater than that of the first plate body.

[0014] The utility model further provides a battery monomer, which comprises:

[0015] A shell has a receiving cavity and an opening in communication with the receiving cavity.

[0016] An electrode assembly is received in the receiving cavity.

[0017] A cover plate assembly as described in the above embodiments covers the opening.

[0018] In some embodiments, the first plate body is received in the shell, and an outer peripheral wall of the welded connecting portion is connected to an inner wall of the shell.

[0019] In some embodiments, the first plate body is partially received in the shell, and a side of the welded connecting portion away from the second plate body is overlapped with an open end of the shell.

[0020] In some embodiments, along a thickness direction of the cover plate assembly, the welded connecting portion has a thickness dimension T1, and the shell has a wall thickness dimension T2, satisfying 0.7≤T1 / T2≤5.

[0021] In some embodiments, the first plate body further includes a main body portion and a thinned portion having a thickness smaller than the main body portion, the thinned portion being connected around an outer periphery of the main body portion, and the welded connecting portion being connected around the thinned portion.

[0022] The thinned portion is provided with a protrusion on a side away from the second plate body, and the protrusion is capable of being received in the opening of the shell.

[0023] An outer edge of the welded connecting portion has a first dimension W1 from the protrusion, and the shell has a wall thickness dimension T2, satisfying 0.7≤W1 / T2≤1.5.

[0024] In some embodiments, the welded connecting portion has a first side surface facing the second plate body, and along a thickness direction of the cover plate assembly, a dimension of the first side surface from the second plate body is d mm, satisfying 0.03≤d≤0.5.

[0025] Embodiments of the present application further provide a battery cell as described in the above embodiments.

[0026] Beneficial effects: The cover plate assembly in the embodiment of the present application is applied to a battery monomer; the cover plate assembly comprises a first plate body and a second plate body; the second plate body is arranged in a stacked manner with the first plate body; a side wall of the first plate body protrudes from a side wall of the second plate body and forms a welding connection part, the welding connection part is connected with an open part of a shell of the battery monomer, and the second plate body is located on a side of the first plate body away from the shell; the structural strength of the second plate body is greater than that of the first plate body. By arranging the second plate body with greater structural strength in a stacked manner on the side of the first plate body away from the shell, the structural strength of the cover plate is enhanced, and meanwhile, the welding connection part is formed on the part of the side wall of the first plate body protruding from the side wall of the second plate body and is connected with the open part of the shell, so that the connection reliability of the cover plate assembly and the shell is improved.

[0027] The battery monomer in the embodiment of the present application comprises the cover plate assembly described in the above embodiment. Therefore, all the technical features and technical effects of the cover plate assembly described above can be achieved, which will not be described herein again.

[0028] The energy storage system in the embodiment of the present application comprises the battery monomer described in the above embodiment. Therefore, all the technical features and technical effects of the battery monomer described above can be achieved, which will not be described herein again. BRIEF DESCRIPTION OF DRAWINGS

[0029] 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 effort on the basis of these drawings.

[0030] Figure 1 It is a structural schematic diagram of the first plate body and the second plate body in the cover plate assembly in the embodiment of the present application in a separated state;

[0031] Figure 2 It is a top view structural schematic diagram of the cover plate assembly in the embodiment of the present application;

[0032] Figure 3 It is a Figure 2 It is a sectional view structural schematic diagram along the A-A direction in the embodiment of the present application;

[0033] Figure 4 It is a Figure 3 It is a local enlarged schematic diagram at B in the embodiment of the present application;

[0034] Figure 5 It is a sectional view structural schematic diagram along the A-A direction of the cover plate assembly in another embodiment of the present application in a top view;

[0035] Figure 6 It is a Figure 5 It is a local enlarged schematic diagram at C in the embodiment of the present application;

[0036] Figure 7 This is a schematic cross-sectional view of the cover plate assembly according to another embodiment of this application, taken from a top view along the AA direction.

[0037] Figure 8 for Figure 7 A magnified view of a portion of point D in the middle;

[0038] Figure 9 This is a schematic diagram of the exploded structure of a single battery cell according to an embodiment of this application;

[0039] Explanation of reference numerals in the attached drawings: 1. Cover plate assembly; 11. First plate; 12. Second plate; 111. Welded connection; 2. Shell; 112. Main body; 113. Thinning part; 114. Protrusion; 3. Electrode assembly; 1110. Outer peripheral wall; 21. Inner wall; 20. Open end; 1111. First side; X. Thickness direction. Detailed Implementation

[0040] 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.

[0041] 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.

[0042] It should also be noted that in the accompanying drawings of this application, the arrow marked X is used to indicate the thickness direction X. In the description of this application, the thickness direction X is introduced to more clearly define the structure and relative positional relationship between the cover assembly 1 and the components in the battery cell.

[0043] As a preamble of the embodiments of the present application, the single cell capacity of the battery is increasing, but with the increase of the single cell capacity of the battery, the size will also increase, and the internal gas generation at the end of the battery will also increase. For the hard shell battery, an aluminum shell is generally used, and the increase of the internal gas generation will cause the deformation of the cover plate to increase, which will affect the sealing reliability and welding reliability of the structure. The general way is to increase the thickness of the cover plate to enhance the structural strength, but the increase of the thickness of the cover plate will cause the cost to rise and the unit volume capacity of the single cell to decrease.

[0044] Therefore, the embodiments of the present application provide a cover plate assembly 1, which aims to solve at least one of the above technical problems.

[0045] Referring to Figures 1 to 8 The embodiments of the present application provide a cover plate assembly 1 applied to a battery single cell; the cover plate assembly 1 comprises a first plate body 11 and a second plate body 12; a first through hole is formed on the first plate body 11, and a second through hole is formed on the second plate body 12; the first through hole and the second through hole are in communication, and are used to assemble a pole to transmit electric quantity between the inside of the battery single cell and the external connector. The second plate body 12 is stacked on the first plate body 11; the side wall of the first plate body 11 protrudes from the side wall of the second plate body 12, and forms a welding connection part 111 connected with the opening of the shell 2 of the battery single cell; the second plate body 12 is located on the side of the first plate body 11 away from the shell 2; the structural strength of the second plate body 12 is greater than that of the first plate body 11. It should be understood that the second plate body 12 with greater structural strength is stacked on the side of the first plate body 11 away from the shell 2, so as to enhance the structural strength of the cover plate, to adapt to the demand of the cover plate strength of the battery single cell with greater capacity, and to prevent the deformation of the cover plate during the use of the battery single cell. At the same time, the welding connection part 111 is formed on the part of the side wall of the first plate body 11 protruding from the side wall of the second plate body 12, and is connected with the opening of the shell 2, so as to improve the connection reliability of the cover plate and the shell 2.

[0046] It should be understood that the material of the first plate body 11 and the shell 2 can be the same, which can reduce the difficulty of welding process, improve the production efficiency, reduce the production cost, make the welding reliability of the first plate body 11 and the shell 2 higher, and ensure the sealing of the connection part of the first plate body 11 and the shell 2. At the same time, the thermal expansion coefficients of the same materials are consistent, and the influence of thermal stress caused by temperature change during the charging and discharging of the battery is smaller, which further enhances the stability and reliability of the overall structure of the battery.

[0047] Referring to Figure 4 , Figure 6 and Figure 8As shown, in some embodiments, the first plate body 11 further comprises a main body portion 112 and a thinned portion 113 with a thickness smaller than the main body portion 112, the thinned portion 113 is connected to the outer periphery of the main body portion 112, and the welding connecting portion 111 is connected to the thinned portion 113. It should be understood that the first plate body 11 is processed to form the main body portion 112 and the thinned portion 113 surrounding the main body portion 112, wherein the thinned portion 113 can be formed by upsetting or extruding the outer edge of the side of the first plate body 11 away from the second plate body 12, and in the process of upsetting, the side wall of the first plate body 11 forms the welding connecting portion 111 protruding from the side wall of the second plate body 12, and the thickness of the welding connecting portion 111 can be the same as or smaller than the thickness of the main body portion 112. The above processing method is simple and efficient. By providing the thinned portion 113 and the welding connecting portion 111 connected to the thinned portion 113, on the one hand, the welding process is easier to control, and the welding connection is more accurate, thereby avoiding the adverse effects of excessive welding heat on the main body portion 112 and other components of the battery, and further improving the reliability and stability of the welding.

[0048] At the same time, the thinned portion 113 can change the stress distribution of the first plate body 11, and when the battery is subjected to external pressure or internal pressure changes, the thinned portion 113 can serve as a stress buffer area and first deform to a certain extent to disperse stress, thereby avoiding stress concentration in the main body portion 112 and causing the plate body to break or be damaged, thereby better protecting the internal structure of the battery and enhancing the overall pressure resistance of the battery.

[0049] Please refer to Figure 6 As shown, in some embodiments, the thinned portion 113 is provided with a protrusion 114 on the side away from the second plate body 12, and the protrusion 114 can be accommodated in the opening of the shell 2. It should be understood that the protrusion 114 can be formed by local extrusion or upsetting of the thinned portion 113, and the protrusion 114 provides positioning for the installation of the cover plate assembly 1, and in the assembly process, the cooperation between the protrusion 114 and the opening of the shell 2 makes the installation of the first plate body 11 and the shell 2 more accurate, effectively avoiding the misalignment problem in the assembly process, and enhancing the stability of the connection between the cover plate assembly 1 and the battery shell 2.

[0050] Please refer to Figure 6As shown, in some embodiments, the partial thinning portion 113 is located on the side of the convex portion 114 away from the welding connecting portion 111. It should be understood that during the local thinning or extrusion process, a sufficient thinning portion 113 is reserved between the main body portion 112 and the formed convex portion 114, which can reduce the impact on the structural strength of the main body portion 112 during the thinning or extrusion process, and ensure the structural integrity of the main body portion 112. On the other hand, under the premise of reducing the weight of the first plate body 11, the overall structural strength of the first plate body 11 is ensured. When the battery is subjected to complex stress, the thinning portion 113 at this position can work together with the thinning portion 113 close to the welding connecting portion 111 to disperse the stress on the battery from different positions and directions.

[0051] In some embodiments, the elastic modulus of the second plate body 12 is greater than the elastic modulus of the first plate body 11. It should be understood that the greater elastic modulus of the second plate body 12 can quickly resist impact and disperse impact force, and the lower elastic modulus of the first plate body 11 further absorbs and buffers the remaining impact force, thereby further improving the impact resistance of the cover plate and ensuring the stability of the battery.

[0052] Referring to Figure 9 As shown, the application also provides a battery monomer, which comprises a shell 2, an electrode assembly 3, and a cover plate assembly 1. The shell 2 has a connected accommodating cavity and an open mouth. The electrode assembly 3 is accommodated in the accommodating cavity. The cover plate assembly 1 is as described in the above embodiments, and the cover plate assembly 1 covers and seals the open mouth. It should be understood that the battery monomer of the application comprises the cover plate assembly 1 as described in the above embodiments, and therefore can have all the technical features and technical effects of the cover plate assembly 1 described above, which will not be repeated here.

[0053] Referring to Figure 4 As shown, in some embodiments, the first plate body 11 is accommodated in the shell 2, and the outer peripheral wall 1110 of the welding connecting portion 111 is connected with the inner wall 21 of the shell 2. It should be understood that the inner wall 21 of the shell 2 and the outer peripheral wall 1110 of the welding connecting portion 111 are connected by welding, so as to provide reliable connection strength between the cover plate assembly 1 and the shell 2, effectively prevent the cover plate assembly 1 and the shell 2 from being separated, and at the same time ensure good sealing performance, prevent electrolyte leakage and external impurities from entering, and ensure stable operation of the battery monomer.

[0054] Referring to Figure 6As shown, in some embodiments, the first plate body 11 is partially accommodated in the shell 2, and the welding connecting portion 111 is overlapped with the open end 20 of the shell 2 away from the second plate body 12. It should be understood that the above assembly process is more convenient, and the part of the first plate body 11 accommodated in the shell 2 can provide installation positioning assistance, which is convenient for aligning the welding connecting portion 111 with the open end 20 of the shell 2 during assembly, reduces the assembly difficulty, improves the assembly efficiency, and reduces the quality problems caused by improper assembly; at the same time, the overlapped mode increases the sealing contact area, and a wider sealing weld can be formed during the welding process, which improves the connection firmness and further improves the sealing of the battery monomer, effectively blocks the leakage of electrolyte and the invasion of external impurities, and guarantees the stable operation of the battery in various complex environments.

[0055] Please refer to Figure 4 As shown, in some embodiments, along the thickness direction X of the cover plate assembly 1, the welding connecting portion 111 has a thickness dimension T1, and the shell 2 has a wall thickness dimension T2, which satisfies 0.7≤T1 / T2≤5. It should be understood that by controlling the ratio between the thickness dimension of the welding connecting portion 111 and the wall thickness dimension of the shell 2 to be between 0.7 and 5, the connection strength of the welding connecting portion 111 and the shell 2 is ensured, and at the same time, the welding connecting portion 111 has sufficient thickness to bear the internal pressure of the battery and various external forces. Specifically, T1 / T2 can be any value in 0.7, 1.2, 1.7, 2.2, 2.7, 3.2, 3.7, 4.2, 4.7, 5.0 or a range value between two values. The greater T1 / T2 is, the greater the thickness dimension of the welding connecting portion 111 is, so that the stress and impact force received by the cover plate assembly 1 can be effectively dispersed, and the welding portion is prevented from cracking or the shell 2 from being damaged due to stress concentration, thereby ensuring the integrity and stability of the battery monomer structure. Furthermore, the thicker welding connecting portion 111 (within a reasonable proportion) can form a wider and denser sealing area after welding, effectively preventing electrolyte leakage and external impurities from entering. The smaller T1 / T2 is, the welding connecting portion 111 is prevented from being excessively thickened, thereby effectively controlling the material cost and the overall weight of the battery under the premise of ensuring the performance of the battery.

[0056] Please refer to Figure 6As shown, in some embodiments, the first plate body 11 further comprises a main body portion 112 and a thinned portion 113 with a thickness smaller than the main body portion 112, the thinned portion 113 is connected to the outer periphery of the main body portion 112, and the welding connecting portion 111 is connected to the thinned portion 113; the thinned portion 113 is provided with a protrusion 114 on the side away from the second plate body 12, and the protrusion 114 can be accommodated in the opening of the shell 2; the outer edge of the welding connecting portion 111 is away from the protrusion 114 by a first size W1, and the shell 2 has a wall thickness size T2, and 0.7≤W1 / T2≤1.5 is satisfied. It should be understood that by controlling W1 / T2 to be between 0.7 and 1.5, it is ensured that the welding connecting portion 111 has a sufficient size for welding connection with the shell 2, so as to ensure the connection strength of the welding connecting portion 111 and the shell 2, while ensuring that the size of the welding connecting portion 111 is reasonably designed, avoiding that the size of the welding connecting portion 111 is too large, reducing the overall structural strength of the first plate body 11, and at the same time, improving the space utilization rate of the battery monomer. Specifically, W1 / T2 can be any value in 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5 or a range value between two values. When W1 / T2 is larger, the distance between the welding connecting portion 111 and the protrusion 114 is larger, and the welding connecting portion 111 has sufficient space for welding operation, ensuring the welding quality and stability. When W1 / T2 is smaller, the protrusion 114 can play a good positioning role, improve the assembly precision, and at the same time, the cooperation between the first plate body 11 and the shell 2 is more compact, further enhancing the sealing performance of the battery monomer.

[0057] Please refer to Figure 8 As shown, in some embodiments, the welding connecting portion 111 has a first side surface 1111 facing the second plate body 12, and the size of the first side surface 1111 away from the second plate body 12 along the thickness direction X of the cover plate assembly 1 is d mm, and 0.03≤d≤0.5 is satisfied. It should be understood that by setting the size of the first side surface 1111 away from the second plate body 12 to be between 0.03 mm and 0.5 mm, the welding connecting portion 111 of the first plate body 11 is facilitated to be welded with the shell 2. Specifically, d can be any value in 0.03, 0.08, 0.13, 0.18, 0.23, 0.28, 0.33, 0.38, 0.43, 0.48, 0.5 or a range value between two values. When d is larger, the influence of the heat generated by welding on the second plate body 12 is smaller, and when d is smaller, the welding size of the welding connecting portion 111 and the shell 2 is larger, the sealing performance is better, and the connection strength is higher.

[0058] The embodiments of the present application also provide a battery monomer, which comprises the battery monomer as described in the above embodiments. Therefore, all the technical features and technical effects of the battery monomer can be achieved.

[0059] 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.

[0060] The above describes in detail a cover plate assembly, a battery monomer and an energy storage system provided by the embodiments of the present application, and the principles and implementation manners of the present 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 ideas of the present application. Those skilled in the art should understand that the technical solutions recorded in the foregoing embodiments can be modified, or some technical features can be replaced equivalently. The 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 present application.

Claims

1. A cover assembly, characterized by The cover plate assembly (1) is applied to a battery monomer, and comprises: a first plate body (11); a second plate body (12) arranged in layers with the first plate body (11); a side wall of the first plate body (11) protrudes from a side wall of the second plate body (12) and forms a welding connecting part (111) connected with an opening of a shell (2) of the battery monomer, and the second plate body (12) is located on a side of the first plate body (11) away from the shell (2); the structural strength of the second plate body (12) is greater than that of the first plate body (11).

2. The cover plate assembly of claim 1, wherein, The first plate body (11) further comprises a main body part (112) and a thinning part (113) with a thickness smaller than that of the main body part (112), the thinning part (113) is connected around the outer periphery of the main body part (112), and the welding connecting part (111) is connected around the thinning part (113).

3. The cover plate assembly of claim 2, wherein, The thinning part (113) is provided with a protruding part (114) on a side away from the second plate body (12), and the protruding part (114) can be accommodated in the opening of the shell (2).

4. The cover plate assembly of claim 3, wherein, Part of the thinning part (113) is located on a side of the protruding part (114) away from the welding connecting part (111).

5. The cover plate assembly of claim 1, wherein, The elastic modulus of the second plate body (12) is greater than that of the first plate body (11).

6. A battery cell characterized by, The cover plate assembly (1) comprises: a shell (2) having a containing cavity and an opening in communication; an electrode assembly (3) accommodated in the containing cavity; The cover plate assembly (1) according to any one of claims 1 to 5, wherein the cover plate assembly (1) covers and seals the opening.

7. The battery cell of claim 6, wherein, The first plate body (11) is accommodated in the shell (2), and an outer peripheral wall (1110) of the welding connecting part (111) is connected with an inner wall (21) of the shell (2).

8. The battery cell of claim 6, wherein, Part of the first plate body (11) is accommodated in the shell (2), and a side of the welding connecting part (111) away from the second plate body (12) is overlapped with an opening end (20) of the shell (2).

9. The battery cell according to claim 7 or 8, characterized in that, In the thickness direction (X) of the cover plate assembly (1), the welding connecting part (111) has a thickness dimension T1, and the shell (2) has a wall thickness dimension T2, and 0.7≤T1 / T2≤5 is satisfied.

10. The battery cell of claim 8, wherein, The first plate body (11) further comprises a main body part (112) and a thinning part (113) with a thickness smaller than that of the main body part (112), the thinning part (113) is connected around the outer periphery of the main body part (112), and the welding connecting part (111) is connected around the thinning part (113); The thinning part (113) is provided with a protruding part (114) on a side away from the second plate body (12), and the protruding part (114) can be accommodated in the opening of the shell (2); An outer edge of the welding connecting part (111) is away from the protruding part (114) by a first dimension W1, the shell (2) has a wall thickness dimension T2, and 0.7≤W1 / T2≤1.5 is satisfied.

11. The battery cell of claim 7, wherein, The welding connecting part (111) has a first side surface (1111) facing the second plate body (12), and the distance between the first side surface (1111) and the second plate body (12) along the thickness direction (X) of the cover plate assembly (1) is d mm, satisfying 0.03≤d≤0.

5.

12. An energy storage system characterized by, A battery cell as claimed in any one of claims 6 to 11.

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