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 in the embodiment of the utility model is suitable for being connected with a shell of a battery monomer, the cover plate assembly comprises a first plate body and a second plate body, and the first plate body is provided with a first through hole; the first plate body is provided with a first through hole, the second plate body is provided with a second through hole, the first through hole is communicated with the second through hole, the second plate body and the first plate body are stacked and attached, and the side, away from the first plate body, of the second plate body is connected with the shell; the first plate body and the second plate body are made of different materials, and the elastic modulus of the first plate body is larger than that of the second plate body. According to the cover plate assembly, the first plate body and the second plate body are combined, the cost is reasonably controlled while the structural strength of the cover plate assembly is improved, and good connection is achieved.

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 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, the cover plate assembly is prone to deformation at the end of the battery. CONTENT OF THE UTILITY MODEL

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

[0005] TECHNICAL SCHEME: The cover plate assembly in the embodiment of the application is suitable for being connected with a shell of a battery monomer, and comprises:

[0006] A first plate body is provided with a first through hole;

[0007] A second plate body is provided with a second through hole, the first through hole and the second through hole are in communication, the second plate body is arranged in a stack with the first plate body and is attached to the first plate body, and the second plate body is connected with the shell on the side away from the first plate body;

[0008] The material of the first plate body is different from that of the second plate body, and the elastic modulus of the first plate body is greater than that of the second plate body.

[0009] In some embodiments, the second plate body comprises a main body part and a connecting part, the connecting part is connected to the outer periphery of the main body part in a ring shape, and the side away from the first plate body is connected with the shell, and the main body part can be partially accommodated in the shell.

[0010] In some embodiments, the second plate body comprises a main body part and a step part connected to the outer periphery of the main body part, the step part has a first section and a second section connected in sequence, the first section is connected to the main body part, and the second section is connected to one end of the first section away from the main body part, the main body part and the first section are accommodated in the shell, and the second section is connected with the shell on the side away from the first plate body.

[0011] In some embodiments, the cover plate assembly further comprises a composite layer, and the composite layer is located at the connection between the first plate body and the second plate body.

[0012] The composite layer is made by any one of hot-pressing, cold-pressing or continuous casting.

[0013] In some embodiments, the ratio of the elastic modulus of the first plate body to the elastic modulus of the second plate body is M, satisfying 2≤M≤4.

[0014] In some embodiments, the elastic modulus G1 of the first plate body satisfies 180GPa≤G1≤230GPa.

[0015] The elastic modulus G2 of the second plate body satisfies 60GPa≤G2≤90GPa.

[0016] In some embodiments, the second plate body is made of aluminum alloy, and the first plate body is made of low-carbon steel or stainless steel.

[0017] In some embodiments, the first plate body has a plurality of first plate bodies, each of which extends along the length direction of the cover plate assembly and is arranged at intervals along the width direction of the cover plate assembly.

[0018] The application also discloses a battery monomer, comprising:

[0019] A shell has a receiving cavity and an opening in communication;

[0020] An electrode assembly is received in the receiving cavity;

[0021] The cover plate assembly as described in the above embodiments covers and seals the opening.

[0022] In some embodiments, the second plate body and the shell are made of the same material.

[0023] The application also discloses an energy storage system comprising the battery monomer as described in the above embodiments.

[0024] Beneficial effects: The cover plate assembly in the embodiment of the application is suitable for being connected with the shell of the battery monomer, and the cover plate assembly comprises a first plate body and a second plate body, the first plate body is provided with a first through hole, the second plate body is provided with a second through hole, the first through hole and the second through hole are in communication, the second plate body is arranged in a laminated manner with the first plate body and is attached to the first plate body, the second plate body is connected with the shell on a side away from the first plate body, the material of the first plate body is different from that of the second plate body, and the elastic modulus of the first plate body is greater than that of the second plate body. The first plate body with a relatively large elastic modulus can provide a relatively high structural strength, and is not prone to large deformation when subjected to external force impact or pressure, thereby ensuring that the cover plate assembly as a whole has a certain rigidity, maintaining the stability of the shape and structure thereof, and playing a good protection role on the battery monomer. The second plate body with a relatively small elastic modulus has better flexibility or processability, so that the second plate body can be better attached to the shell (such as welding), improving the tightness and reliability of the connection and reducing problems such as leakage caused by loose connection. Through the composite form of the first plate body and the second plate body, the structural strength of the cover plate assembly is improved, the cost is reasonably controlled, and good connection is achieved.

[0025] The battery monomer of the embodiment of the 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 had, and details are not repeated here.

[0026] The energy storage system of the embodiment of the 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 had, and details are not repeated here. BRIEF DESCRIPTION OF DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the application, the drawings needed to be used in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can be obtained by those skilled in the art without creative labor.

[0028] Figure 1 It is an exploded schematic view of the cover plate assembly of the embodiment of the application, and only the first plate body and the second plate body are shown in the figure;

[0029] Figure 2 It is a top view structural schematic view of the cover plate assembly of the embodiment of the application;

[0030] Figure 3 It is Figure 2 a sectional view in the direction of A-A;

[0031] Figure 4 It is Figure 3 a local enlarged schematic view of B in the figure;

[0032] Figure 5 As another embodiment of this application Figure 2 Cross-sectional view along the AA direction;

[0033] Figure 6 for Figure 5 A magnified view of a portion of point C in the middle;

[0034] Figure 7 This is a top view of a cover plate assembly according to another embodiment of this application;

[0035] Figure 8 for Figure 7 A cross-sectional view along the DD direction;

[0036] Figure 9 This is an exploded view of a single battery cell according to an embodiment of this application;

[0037] Explanation of reference numerals in the attached drawings: 1. Housing; 2. Cover plate assembly; 21. First plate; 22. Second plate; 210. First through hole; 220. Second through hole; 221. Main body; 222. Connecting part; 223. Stepped part; 2231. First section; 2232. Second section; 3. Electrode assembly; X, length direction; Y, width direction. Detailed Implementation

[0038] 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.

[0039] 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.

[0040] It should be noted that in the drawings of the present application, the arrow marked X indicates the length direction X, and the arrow marked Y indicates the width direction Y. In the description of the present application, the length direction X and the width direction Y are introduced to more clearly define the structure and relative position relationship of the components in the cover plate assembly 2.

[0041] As a preamble to the embodiments of the present application, the single cell capacity of the battery is increasing, and a large single cell battery can directly reduce the cost per watt-hour of the battery. However, with the increase of the single cell capacity of the battery, the size of the single cell battery will also increase, and the internal gas production at the end of the battery will also increase. For hard-shell batteries, an aluminum shell is generally used, and the increase of the internal gas production will lead to an increase of the deformation of the top cover, affecting the sealing reliability and welding reliability of the structure. Generally, the thickness of the top cover sheet is increased to enhance the structural strength, but the increase of the thickness of the cover plate will lead to an increase of the cost and a decrease of the unit volume capacity of the single cell battery.

[0042] Therefore, the present application provides a cover plate assembly to solve at least one of the above technical problems.

[0043] Please refer to Figures 1 to 8 As shown in the drawings, the cover plate assembly 2 provided by the present application is suitable for connecting with the shell 1 of the battery single cell, and the cover plate assembly 2 comprises a first plate body 21 and a second plate body 22. The first plate body 21 is provided with a first through hole 210, and the second plate body 22 is provided with a second through hole 220. The first through hole 210 and the second through hole 220 are in communication, the second plate body 22 is arranged in a stacked manner with the first plate body 21 and is attached thereto, and the second plate body 22 is connected with the shell 1 on the side away from the first plate body 21. The material of the first plate body 21 and the second plate body 22 is different, and the elastic modulus of the first plate body 21 is greater than that of the second plate body 22. The first plate body 21 with a relatively large elastic modulus can provide a relatively high structural strength, and is not easy to deform greatly when subjected to external force impact or pressure, thereby ensuring that the cover plate assembly 2 as a whole has a certain rigidity and maintains the stability of its shape and structure, and plays a good protective role for the battery single cell. The second plate body 22 with a relatively small elastic modulus has better flexibility or processability, so that the second plate body 22 can be better attached to the shell 1 (such as welding), thereby improving the tightness and reliability of the connection and reducing the leakage problem caused by the loose connection. Through the composite form of the first plate body 21 and the second plate body 22, the structural strength of the cover plate assembly 2 is improved, the cost is reasonably controlled, and good connection is achieved.

[0044] In some embodiments, the second plate body 22 can be made of an aluminum alloy material. The aluminum alloy has a relatively light weight, and can reduce the overall weight of the battery single cell while ensuring the strength. The first plate body 21 can be made of a material with a higher elastic modulus than the aluminum alloy, such as steel or titanium.

[0045] Please see Figures 2 to 4 As shown, in some embodiments, the second plate 22 includes a main body 221 and a connecting part 222. The connecting part 222 surrounds the outer periphery of the main body 221 and is connected to the housing 1 on the side opposite to the first plate 21. The main body 221 can be partially housed within the housing 1. It should be understood that the design of the connecting part 222 surrounding the main body 221 improves the stability of the second plate 22. At the same time, the connection of the connecting part 222 to the housing 1 on the side opposite to the first plate 21 provides a larger contact area, facilitating the connection to the housing 1 and improving the reliability of the connection between the second plate 22 and the housing 1. Furthermore, by placing the connecting part 222 at the opening of the housing 1, it facilitates the positioning of the welding position between the connecting part 222 and the housing 1, reducing welding difficulty and improving welding efficiency. When the second plate 22 is connected to the housing 1, the connecting part 222 can effectively prevent external moisture, dust and other impurities from entering the battery cell, preventing these impurities from corroding or damaging the electrodes, electrolyte and other components inside the battery, thereby ensuring the performance and service life of the battery cell. Furthermore, the main body 221 of the second plate 22 can be partially housed inside the housing 1, allowing the cover assembly 2 to better adapt to the internal structure of the battery cell and improving the overall mechanical performance and protective capability of the cover assembly 2.

[0046] Please see Figure 2 , Figure 5 and Figure 6 As shown, in some embodiments, the second plate 22 includes a main body 221 and a stepped portion 223 surrounding and connected to the outer periphery of the main body 221. The stepped portion 223 has a first segment 2231 and a second segment 2232 connected together. The first segment 2231 is connected to the main body 221, and the second segment 2232 is connected to the end of the first segment 2231 away from the main body 221. The main body 221 and the first segment 2231 are housed within the housing 1. The side of the second segment 2232 facing away from the first plate 21 is connected to the housing 1. It should be understood that the design of the stepped portion 223 makes the connection between the second plate 22 and the housing 1 more stable. The connection of the side of the second segment 2232 facing away from the first plate 21 to the housing 1 increases the connection area and improves the reliability of the connection between the second plate 22 and the housing 1. Furthermore, the stepped structure can withstand greater tensile and shear forces. When the battery is subjected to vibration or external impact, the structure of the step portion 223 can disperse the stress and prevent the connection portion 222 from being damaged due to concentrated force, thereby ensuring a reliable connection between the cover plate assembly 2 and the housing 1 and protecting the structural integrity of the battery cell.

[0047] It should also be understood that the main body 221 of the second plate body 22 and the first section 2231 are accommodated in the shell 1, so that the center of gravity of the second plate body 22 is lowered into the shell 1, thereby improving the stability of the second plate body 22 and improving the mechanical strength and protection capability of the cover plate assembly 2 as a whole.

[0048] Further, the second section 2232 of the stepped portion 223 is connected with the shell 1, so that the first plate body 21 is located on the outer side, which can avoid the first plate body 21 from contacting the electrolyte and avoid the potential difference between the two metals from causing oxidation-reduction reaction and metal corrosion in the electrolyte environment.

[0049] Specifically, in some embodiments, the second plate body 22 is structurally identical to the first plate body 21, and the first plate body 21 entirely covers the side of the second plate body 22 away from the shell 1.

[0050] In some embodiments, the cover plate assembly 2 further comprises a composite layer (not shown) located at the connection between the first plate body 21 and the second plate body 22, which is made by any one of hot-pressing, cold-pressing or continuous casting. It should be understood that the composite layer is located at the connection between the first plate body 21 and the second plate body 22 and is made by hot-pressing, cold-pressing or continuous casting, which can form a more firm combination between the first plate body 21 and the second plate body 22. Hot-pressing promotes the molecular diffusion and fusion of the two materials under the action of heating and pressing, thereby enhancing the bonding force of the interface; cold-pressing relies on strong pressure to make the material surfaces tightly contact, thereby forming mechanical occlusion and physical adsorption; continuous casting can realize metallurgical combination between the first plate body 21 and the second plate body 22 during the plate forming process. The above processes can effectively improve the connection strength between the first plate body 21 and the second plate body 22, prevent separation or loosening during use, and ensure the structural stability of the cover plate assembly 2.

[0051] In some embodiments, the ratio of the elastic modulus of the first plate body 21 to the elastic modulus of the second plate body 22 is M, satisfying 2≤M≤4. It needs to be understood that by setting the ratio of the elastic modulus of the first plate body 21 to the elastic modulus of the second plate body 22 to be between 2 and 4, the elastic modulus of the first plate body 21 is relatively high, which can bear the main structural support and resist deformation of external force; when the battery is subjected to external extrusion or impact, the shape of the cover plate assembly 2 can be effectively maintained stable, and the internal structure of the battery is protected. The elastic modulus of the second plate body 22 is relatively low, and has a certain flexibility, which can better adapt to the shape and surface condition of the shell 1 when connected with the shell 1, and realize close connection. Through the difference of the elastic modulus, the two are matched with each other, which optimizes the connection performance while ensuring the structural strength, and improves the overall reliability of the cover plate assembly 2. At the same time, by setting the ratio of the elastic modulus of the first plate body 21 to the elastic modulus of the second plate body 22 to be within the above range, the stress can be more effectively dispersed and relieved when the cover plate assembly 2 is subjected to external force. When the cover plate assembly 2 is subjected to external force, the first plate body 21 deforms less, and the second plate body 22 deforms more, so that the stress will not be concentrated in a certain part, thereby reducing the risk of local damage of the cover plate assembly 2 and prolonging its service life.

[0052] In some embodiments, the elastic modulus G1 of the first plate body 21 satisfies 180GPa≤G1≤230GPa; the elastic modulus G2 of the second plate body 22 satisfies 60GPa≤G2≤90GPa. It needs to be understood that the first plate body 21 has high stiffness and strength in the elastic modulus range of 180GPa to 230GPa, which can effectively resist larger external force; the second plate body 2260GPa to 90GPa has a certain flexibility and plasticity, which is convenient for close connection with the shell 1 of the battery monomer, and can produce appropriate deformation to disperse stress and avoid local damage caused by stress concentration when subjected to external force.

[0053] In some embodiments, the first plate can be selected from low carbon steel, stainless steel, titanium alloy and the like, and the second plate body 22 can be selected from aluminum alloy, copper alloy, magnesium alloy.

[0054] Please refer to Figure 7 and Figure 8As shown, in some embodiments, the first plate body 21 has a plurality of first plate bodies 21, each of which extends along the length direction X of the cover plate assembly 2 and is arranged at intervals along the width direction Y of the cover plate assembly 2. It should be understood that the combination of the first plate body 21 and the second plate body 22 can be a local combination of a plurality of first plate bodies 21 and second plate bodies 22. The plurality of first plate bodies 21 can provide more uniform support in the width direction Y of the cover plate assembly 2. When the cover plate assembly 2 is subjected to external force, whether it is pressure from above or impact force from the side, the plurality of first plate bodies 21 can disperse stress, avoid local stress concentration, and reduce deformation or damage caused by excessive stress on a single plate body, thereby effectively enhancing the overall structural strength and stability of the cover plate assembly 2, better protecting the structure and components inside the battery. Furthermore, due to the high elastic modulus of the first plate body 21, the arrangement of the plurality of first plate bodies 21 further improves the overall rigidity of the cover plate assembly 2. This improvement in rigidity helps maintain the shape of the cover plate assembly 2, especially during the charging and discharging process of the battery, where the battery may expand or contract. The plurality of first plate bodies 21 can limit the deformation of the cover plate assembly 2, ensuring the stability of the space inside the battery, and facilitating the stable performance of the battery. At the same time, the intervals between different first plate bodies 21 can make the cover plate assembly 2 have a certain elasticity to a certain extent, which can buffer the impact of external force and optimize the mechanical properties.

[0055] By reasonably setting the size and interval of the plurality of first plate bodies 21, the amount of first plate body 21 material can be reduced while ensuring the performance of the cover plate assembly 2. Compared to using a large area of first plate body 21 material, the plurality of first plate bodies 21 arranged at intervals can more effectively utilize the material and reduce costs, while improving the strength of the cover plate assembly 2 and further reducing the weight of the cover plate assembly 2.

[0056] Please refer to Figure 9 As shown, the present application also discloses a battery monomer, comprising a shell 1, an electrode assembly 3 and a cover plate assembly 2; the shell 1 has a communication accommodating cavity and an opening; the electrode assembly 3 is accommodated in the accommodating cavity; the cover plate assembly 2 of the above-mentioned embodiment seals the opening. The battery monomer of the present application comprises the cover plate assembly 2 as described in the above-mentioned embodiment. Therefore, it can have all the technical features and technical effects of the cover plate assembly 2 described above, which will not be repeated here.

[0057] In some embodiments, the second plate body 22 is made of the same material as the shell 1. It should be understood that the second plate body 22 and the shell 1 are made of the same material, and the melting point of the same material is the same, and the welding effect is better. Under the action of welding heat, it is easier to realize the diffusion and fusion between atoms, form a firm welding joint, at the same time, can reduce the generation of welding defects (such as pores, cracks, etc.), improve the welding strength and sealing performance, ensure the reliability of the connection between the cover plate assembly 2 and the shell 1.

[0058] During the charging and discharging process of the battery, heat is generated inside the battery, causing the temperature to rise. The second plate body 22 and the shell 1 of the same material have similar thermal expansion coefficients, and when the temperature changes, they will expand or contract to a similar degree, thereby avoiding thermal stress caused by differences in thermal expansion and reducing structural deformation, cracking and other problems caused by thermal stress, improving the structural stability and safety of the battery monomer. At the same time, the second plate body 22 and the shell 1 of the same material also have better consistency in heat conduction. Heat can be more evenly transferred between the two, which is conducive to the dissipation of heat inside the battery, reduces the risk of local overheating, and improves the performance and service life of the battery.

[0059] The application also discloses an energy storage system comprising the battery monomer as described above. Therefore, all the technical features and technical effects of the battery monomer described above can be achieved, and the description is not repeated here.

[0060] 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 related description of other embodiments.

[0061] The above describes in detail the cover plate assembly 2, the battery monomer and the energy storage system provided by the embodiments of the application, and the principle and implementation manner of the application are described by applying specific examples. The above description of the embodiments is only used to help understand the technical solutions of the application and its core idea; those skilled in the art should understand that the technical solutions recorded in the above embodiments can still be modified, or some technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the application.

Claims

1. A cover plate assembly, characterized by Suitable for connecting with a shell (1) of a battery monomer, the cover plate assembly (2) comprises: A first plate body (21) is provided with a first through hole (210); A second plate body (22) is provided with a second through hole (220), the first through hole (210) and the second through hole (220) are through, the second plate body (22) and the first plate body (21) are arranged in layers and are fitted, the second plate body (22) is connected with the shell (1) on the side away from the first plate body (21); The first plate body (21) and the second plate body (22) are different in material, and the elastic modulus of the first plate body (21) is greater than that of the second plate body (22).

2. The cover plate assembly of claim 1, wherein, The second plate body (22) comprises a main body part (221) and a connecting part (222), the connecting part (222) is connected around the outer periphery of the main body part (221), and the side away from the first plate body (21) is connected with the shell (1), and the main body part (221) can be partially accommodated in the shell (1).

3. The cover plate assembly of claim 1, wherein, The second plate body (22) comprises a main body part (221) and a step part (223) connected around the outer periphery of the main body part (221), the step part (223) has a first segment (2231) and a second segment (2232) connected, the first segment (2231) is connected with the main body part (221), and the second segment (2232) is connected to one end of the first segment (2231) away from the main body part (221), the main body part (221) and the first segment (2231) are accommodated in the shell (1), and the second segment (2232) is connected with the shell (1) on the side away from the first plate body (21).

4. The cover plate assembly of claim 1, wherein, The cover plate assembly (2) further comprises a composite layer, which is located at the connection of the first plate body (21) and the second plate body (22); The composite layer is made by any one of hot pressing, cold pressing or continuous casting.

5. The cover plate assembly of claim 1, wherein, The ratio of the elastic modulus of the first plate body (21) to the elastic modulus of the second plate body (22) is M, which satisfies 2≤M≤4.

6. The cover plate assembly of claim 5, wherein, The elastic modulus G1 of the first plate body (21) satisfies 180GPa≤G1≤230GPa; The elastic modulus G2 of the second plate body (22) satisfies 60GPa≤G2≤90GPa.

7. The cover plate assembly of claim 1, wherein, The second plate body (22) is made of aluminum alloy, and the first plate body (21) is made of low carbon steel or stainless steel.

8. The cover plate assembly of claim 1, wherein, The first plate body (21) has a plurality of first plate bodies (21), and the plurality of first plate bodies (21) extend along the length direction (X) of the cover plate assembly (2) and are arranged at intervals along the width direction (Y) of the cover plate assembly (2).

9. A battery cell characterized by, Comprise: A shell (1) has a receiving cavity and an opening connected in communication; An electrode assembly (3) is accommodated in the receiving cavity; The cover plate assembly (2) of any one of claims 1 to 8, the cover plate assembly (2) covers and seals the opening.

10. The battery cell of claim 9, wherein, The second plate body (22) and the shell (1) are the same in material.

11. An energy storage system characterized by, The battery monomer of any one of claims 9 to 10.

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