Secondary batteries

Abstract

This application provides a secondary battery, comprising: a casing with an opening; a separator inside the casing dividing the casing into a positive electrode chamber and a negative electrode chamber located on opposite sides of the separator, and a membrane chamber located inside the separator; wherein a positive electrode material is disposed in the positive electrode chamber, a lithium plate is disposed in the negative electrode chamber, and a membrane is disposed in the membrane chamber; current collectors, including a first current collector disposed in the positive electrode chamber and a second current collector disposed in the negative electrode chamber, the first current collector being connected to the positive electrode material and the second current collector being connected to the lithium plate; and a cover plate disposed at the opening, the cover plate including a positive electrode post and a negative electrode post respectively connected to the first current collector and the second current collector. This application can improve the battery energy density while reducing the risk of short circuits caused by lithium dendrites piercing the separator.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, specifically to a secondary battery. Background Technology

[0002] Current lithium battery manufacturing processes and assembly methods result in relatively low energy densities. For example, the energy density of lithium iron phosphate batteries is typically below 200 Wh / kg, while that of ternary lithium batteries ranges from 200 to 300 Wh / kg. This limitation in energy density makes it difficult for lithium-ion batteries to meet the growing development demands, thus restricting their application in various scenarios.

[0003] To address this issue, a commonly adopted improvement method is to use lithium metal as the negative electrode in lithium-ion batteries. Lithium metal boasts a theoretical specific capacity of up to 3860 mAh / g, significantly improving the battery's energy density compared to graphite's 372 mAh / g. However, the uneven surface of lithium metal and variations in electrodeposition rates lead to uneven deposition, which can easily result in the formation of dendritic lithium crystals during use. These lithium dendrites not only reduce battery capacity but may also puncture the separator, causing a short circuit. Utility Model Content

[0004] In order to overcome the defects in the prior art, this utility model provides a secondary battery that can improve the battery energy density while reducing the risk of short circuit caused by lithium dendrites piercing the separator.

[0005] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0006] This utility model discloses a secondary battery, comprising:

[0007] The housing has an opening and a partition inside the housing, which divides the housing into a positive electrode chamber and a negative electrode chamber located on both sides of the partition, and a membrane chamber located inside the partition. The positive electrode chamber contains a positive electrode material, the negative electrode chamber contains a lithium plate, and the membrane chamber contains a membrane.

[0008] The current collector includes a first current collector disposed in the positive electrode chamber and a second current collector disposed in the negative electrode chamber, wherein the first current collector is connected to the positive electrode material and the second current collector is connected to the lithium plate;

[0009] A cover plate is disposed at the opening, and the cover plate includes a positive terminal and a negative terminal respectively connected to the first current collector and the second current collector.

[0010] This application divides the casing into multiple independent chambers, each housing the positive electrode, negative electrode, and separator, thereby separating the battery's positive electrode, negative electrode, and separator. This reduces the risk of lithium dendrites piercing the separator during charging and discharging, significantly improving battery safety. Furthermore, placing the positive electrode material directly within the positive electrode chamber not only increases the battery's energy density but also simplifies the manufacturing process, shortens the manufacturing cycle, and ultimately reduces energy consumption.

[0011] Furthermore, the partition plate has a first groove on the side facing the negative electrode chamber, and the negative electrode chamber has a second groove on the side opposite to the partition plate, corresponding to the position of the first groove. Both ends of the lithium plate are respectively inserted into the first groove and the second groove. The method and structure of fixing the lithium plate with the first and second grooves are simple, and they also guide the lithium plate, making installation more convenient and faster.

[0012] Furthermore, the positive electrode chamber is provided with a base plate, and the base plate has mounting holes. The first current collector is inserted into the mounting holes and connected and fixed to the base plate. The base plate can provide stable support for the first current collector, ensuring stable current transmission within the positive electrode chamber.

[0013] Furthermore, the partition includes a first partition and a second partition spaced apart, and the first partition, the second partition, and the inner wall of the shell surround to form the diaphragm chamber. Both the first partition and the second partition are provided with through holes. These through holes are used to connect the positive electrode chamber and the negative electrode chamber, enabling the transport of electrolyte.

[0014] Furthermore, the battery has multiple through holes, which are spaced apart on the first and second separators. The multiple through holes increase the flow channels between the positive and negative electrode chambers, thereby improving the transport efficiency of the electrolyte and lithium ions inside the battery.

[0015] Furthermore, the cross-sectional area of ​​the through-hole and the area of ​​the separator satisfy: S1 ≥ 0.5S2, where S1 is the sum of the cross-sectional areas of the through-holes on the side of the separator facing the positive or negative electrode chamber, and S2 is the side area of ​​the separator facing the positive or negative electrode chamber. This relationship between the cross-sectional area of ​​the through-hole and the area of ​​the separator ensures that the electrolyte passes through the through-holes on the separator sufficiently and efficiently, preventing electrolyte accumulation or blockage during flow, thereby ensuring stable battery operation.

[0016] Furthermore, the separator is made of multilayer polyethylene and / or polypropylene composite material, and the separator has pores. The composite separator has high strength and better stability, and can effectively isolate the positive and negative electrodes, reducing the risk of short circuits.

[0017] Furthermore, the thickness of the separator is 0.5–2 mm. Setting the separator thickness within this range ensures the separator's strength and prevents short-circuit risks caused by an excessively thin separator, while also avoiding an excessively thick separator that would occupy internal space and reduce battery energy density.

[0018] Furthermore, the second current collector is located at the top of the lithium plate, with one end connected to the lithium plate and the other end connected to the negative terminal. This effectively conducts the current generated by the lithium plate to the negative terminal, ensuring stable current transmission.

[0019] Furthermore, multiple lithium plates are provided, and these multiple lithium plates are spaced apart in the negative electrode chamber. The spaced arrangement of multiple lithium plates can reduce the current density of a single lithium plate, reduce the formation of lithium dendrites, and further improve the safety and cycle life of the battery.

[0020] Furthermore, the thickness of the lithium plate is 0.1–1 mm. Setting the thickness of the lithium plate within this range ensures that the lithium plate has high mechanical strength and electrochemical activity, avoids excessively thick lithium plates which could lead to excessively high local current density and uneven lithium ion deposition, and reduces the risk of lithium dendrite formation.

[0021] Due to the application of the above technical solution, this utility model has the following advantages compared with the prior art:

[0022] 1. This application divides the casing into multiple independent chambers, each containing a positive electrode, a negative electrode, and a separator, thereby separating the positive electrode, negative electrode, and separator of the battery. This reduces the risk of lithium dendrites piercing the separator during charging and discharging, and significantly improves the safety performance of the battery.

[0023] 2. This application places the positive electrode material directly in the positive electrode chamber, which can improve the energy density of the battery. Compared with the existing lithium battery manufacturing process, it can eliminate processes such as coating, sheet making, and winding, which not only simplifies the manufacturing process but also shortens the manufacturing cycle, thereby reducing energy consumption.

[0024] To make the above and other objects, features and advantages of this utility model more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1This is a cross-sectional view of a secondary battery provided in an embodiment of this utility model;

[0027] Figure 2 This is an internal view of a secondary battery provided in an embodiment of the present invention;

[0028] Figure 3 This is a first-view view of a housing provided in an embodiment of the present utility model;

[0029] Figure 4 This is a second-view view of a housing provided in an embodiment of the present utility model;

[0030] Figure 5 This is a structural diagram of a secondary battery provided in an embodiment of the present invention.

[0031] The reference numerals in the above figures are as follows: 1. Shell; 2. Separator; 3. Positive electrode chamber; 4. Diaphragm chamber; 5. Negative electrode chamber; 6. Positive electrode material; 7. Diaphragm; 8. Lithium plate; 9. First current collector; 10. Second current collector; 11. First groove; 12. Second groove; 13. Cover plate; 14. Positive electrode post; 15. Negative electrode post; 16. Base plate. Detailed Implementation

[0032] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. In addition, the accompanying drawings of the present invention are only simple schematic illustrations and are not depictions based on actual dimensions, as stated in advance.

[0033] In this utility model, it should be noted that the terms "upper," "lower," "inner," "outer," "forward," "backward," "between," "nearer," and "farthest" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are used only for the convenience of describing this utility model and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. It should also be noted that, unless otherwise explicitly specified and limited, the terms "installation" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0034] It should be understood that while terms such as "first," "second," and "third" may be used in this document to describe various components or signals, these components or signals should not be limited by these terms. These terms are primarily used to distinguish one component from another, or one signal from another. Furthermore, the term "or" as used herein should, as appropriate, include any combination of one or more of the related listed items.

[0035] Reference Figures 1-5 This application provides a secondary battery, including a housing 1, a separator 2 disposed inside the housing 1, and a cover plate 13 connected to the housing 1. The separator 2 divides the housing 1 into multiple independent chambers, each of which is provided with a positive electrode material 6, a separator 7, and a lithium plate 8, thereby separating the positive electrode, negative electrode, and separator of the battery. This reduces the risk of lithium dendrites piercing the separator during charging and discharging, thereby significantly improving the safety performance of the battery.

[0036] Specifically, such as Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, the casing 1 is generally rectangular and has an opening to facilitate the installation of components such as the positive electrode material 6, the separator 7, and the lithium plate 8. Optionally, the casing 1 is made of a corrosion-resistant material, such as metal or plastic, to ensure the overall performance and safety of the battery.

[0037] The partition 2 is a rectangular plate structure that is connected to the inner wall of the shell 1. It divides the interior of the shell 1 along its length into a positive electrode chamber 3 located on one side of the partition 2, a diaphragm chamber 4 located inside the partition 2, and a negative electrode chamber 5 located on the other side of the partition 2.

[0038] The positive electrode material 6 is disposed in the positive electrode chamber 3. In this embodiment, existing methods and materials, such as ternary lithium, lithium iron phosphate, lithium cobalt oxide, etc., are used. The materials are mixed and stirred with conductive agent, binder and solvent NMP to form a paste. After being directly filled into the positive electrode chamber 3 and baked, the positive electrode material 6 is formed. Compared with the existing lithium battery manufacturing process, the coating, sheet making and winding processes are eliminated. The manufacturing process is simple, the process cycle can be shortened and energy consumption can be reduced.

[0039] The diaphragm chamber 4 is used to house the diaphragm 7. Optionally, the diaphragm chamber 4 is formed inside or on the partition plate 2. In this embodiment, the partition plate 2 includes a first partition plate and a second partition plate spaced apart. The first partition plate and the second partition plate, together with the inner wall of the housing 1, form a cavity, which is the diaphragm chamber 4. The diaphragm 7 is directly inserted into the cavity, and through holes are provided on both the first partition plate and the second partition plate to connect the positive electrode chamber 3, the diaphragm chamber 4, and the negative electrode chamber 5, thereby realizing the transport of electrolyte and lithium ions. The first partition plate is closer to the positive electrode chamber 3, and the second partition plate is closer to the negative electrode chamber 5.

[0040] Optionally, the first and second partitions have multiple through holes, which are spaced apart along the length and height of the first and second partitions. The distribution can be uniform or non-uniform; this application does not specifically limit this.

[0041] In one embodiment, the partition 2 is a rectangular plate with an opening, the opening of which faces the same direction as the opening of the housing 1. The interior of the rectangular plate is provided with a receiving space, which forms a diaphragm chamber 4. The sides of the rectangular plate facing the positive electrode chamber 3 and the negative electrode chamber 5 are provided with through holes, and the positive electrode chamber 3, the diaphragm chamber 4 and the negative electrode chamber 5 are connected through the through holes.

[0042] In another embodiment, the separator 2 is a rectangular plate with through holes forming diaphragm chambers 4. A diaphragm 7 is located within the through holes and connected to the wall of the through holes. The positive electrode chamber 3 and the negative electrode chamber 5 are connected through the diaphragm 7. Optionally, the separator 2 has multiple through holes to connect multiple diaphragms 7, thereby improving the transport efficiency of the electrolyte and lithium ions.

[0043] The shape and size of the through holes on the partition 2 can be flexibly set. The cross-sectional area of ​​the through holes and the area of ​​the partition 2 satisfy: S1≥0.5S2, where S1 is the sum of the cross-sectional areas of the through holes on the side of the partition 2 facing the positive electrode chamber 3 or the negative electrode chamber 5, and S2 is the side area of ​​the partition 2 facing the positive electrode chamber 3 or the negative electrode chamber 5.

[0044] In some embodiments, the partition 2 is integrally formed with the housing 1 or is disposed within the housing 1 by welding, and its material is a corrosion-resistant material, such as metal or plastic.

[0045] In this embodiment, the separator 7 is made of a multilayer polyethylene and / or polypropylene composite material, and the separator 7 has pores to allow the electrolyte and lithium ions to pass through. Optionally, the thickness of the separator 7 is 0.5 to 2 mm, and the volume occupied by the pores on the separator 7 satisfies a porosity of 30% to 60%. In other embodiments, the separator 7 may also be formed using other known composite materials, which will not be described in detail here.

[0046] The lithium plate 8 is disposed within the negative electrode chamber 5. The lithium plate 8 has a plate-like structure and is made of lithium metal. To fix the lithium plate 8, a first groove 11 is provided on the side of the separator 2 facing the negative electrode chamber 5, and a second groove 12 corresponding to the position of the first groove 11 is provided on the side of the negative electrode chamber 5 opposite to the separator 2. The lithium plate 8 is fixed within the negative electrode chamber 5 by being inserted into the first groove 11 and the second groove 12, and the lithium plate 8 is perpendicular to the separator 7 to facilitate lithium ion transport. The number of the first groove 11 and the second groove 12 can be flexibly set according to the number and position of the lithium plates 8.

[0047] In this embodiment, the first groove 11 is disposed on the second partition plate and extends along the height and width directions of the second partition plate. The distance it extends along the width direction of the second partition plate is less than the width of the second partition plate, allowing the lithium plate 8 to approach the separator 7 from the end face of the second partition plate without contacting it, thereby reducing the risk of lithium dendrites piercing the separator 7. The width direction of the second partition plate is parallel to the length direction of the housing 1. The shape and size of the second groove 12 match those of the first groove 11, which will not be described further here.

[0048] like Figure 2 As shown, multiple lithium plates 8 are provided, and the multiple lithium plates 8 are spaced apart in the negative electrode chamber 5. Optionally, the thickness of any lithium plate 8 is 0.1 to 1 mm.

[0049] The positive electrode material 6 and the lithium plate 8 are connected to the cover plate 13 via current collectors. Specifically, the cover plate 13 is located at the opening of the housing 1 and includes a positive electrode post 14 and a negative electrode post 15. The current collectors include a first current collector 9 located in the positive electrode chamber 3 and a second current collector 10 located in the negative electrode chamber 5. The first current collector 9 is connected to the positive electrode material 6 and the positive electrode post 14, respectively, and the second current collector 10 is connected to the lithium plate 8 and the negative electrode post 15, respectively.

[0050] like Figure 1 and Figure 2 As shown, the first current collector 9 is a rod-shaped structure, which is inserted into the positive electrode material 6 and connected to it. In this embodiment, a base plate 16 is provided in the positive electrode chamber 3, and the base plate 16 is provided with mounting holes. The first current collector 9 is connected and fixed to the base plate 16 by being inserted into the mounting holes.

[0051] Optionally, there may be multiple first current collectors 9, which are spaced apart within the positive electrode chamber 3. In this embodiment, when multiple first current collectors 9 are provided, the positive electrode post 14 extends along the arrangement direction of the multiple first current collectors.

[0052] The second current collector 10 is a block structure located at the top of the lithium plate 8, with one end connected to the lithium plate 8 and the other end connected to the negative electrode post 15. The number of second current collectors 10 can be flexibly set according to the number of lithium plates 8. When multiple second current collectors 10 are set, the negative electrode post 15 extends along the arrangement direction of the multiple second current collectors.

[0053] The specific manufacturing method of the secondary battery in this application embodiment is as follows: the first current collector 9 is inserted into the positive electrode chamber 3, the prepared paste-like positive electrode slurry is filled into the positive electrode chamber 3, after baking to remove the solvent NMP, the separator 7 and the lithium plate 8 are respectively installed into the separator chamber 4 and the negative electrode chamber 5, the first current collector 9 is connected to the positive electrode post 14, the second current collector 10 is connected to the negative electrode post 15, the electrolyte is injected into the shell 1, the cover plate 13 is sealed to the shell 1, and the battery is formed, capacity tested and tested according to the existing process to complete the battery manufacturing.

[0054] This utility model uses specific embodiments to illustrate the principle and implementation of the utility model. The above description of the embodiments is only for the purpose of helping to understand the method and core idea of ​​the utility model. At the same time, for those skilled in the art, there will be changes in the specific implementation and application scope based on the idea of ​​the utility model. Therefore, the content of this specification should not be construed as a limitation of the utility model.

Claims

1. A secondary battery, characterized in that, include: The housing has an opening and a partition inside the housing, which divides the housing into a positive electrode chamber and a negative electrode chamber located on both sides of the partition, and a membrane chamber located inside the partition. The positive electrode chamber contains a positive electrode material, the negative electrode chamber contains a lithium plate, and the membrane chamber contains a membrane. The current collector includes a first current collector disposed in the positive electrode chamber and a second current collector disposed in the negative electrode chamber, wherein the first current collector is connected to the positive electrode material and the second current collector is connected to the lithium plate; A cover plate is disposed at the opening, and the cover plate includes a positive terminal and a negative terminal respectively connected to the first current collector and the second current collector.

2. A secondary battery according to claim 1, characterized in that, The partition has a first groove on the side facing the negative electrode chamber, and the negative electrode chamber has a second groove on the side opposite to the partition, corresponding to the position of the first groove. The two ends of the lithium plate are respectively inserted into the first groove and the second groove.

3. A secondary battery according to claim 1, characterized in that, The positive electrode chamber is provided with a base plate, and the base plate is provided with mounting holes. The first current collector is inserted into the mounting holes and connected and fixed to the base plate.

4. A secondary battery according to claim 1, characterized in that, The partition includes a first partition and a second partition spaced apart. The first partition, the second partition, and the inner wall of the shell form the diaphragm chamber. Both the first partition and the second partition are provided with through holes.

5. A secondary battery according to claim 4, characterized in that, The cross-sectional area of ​​the through hole and the area of ​​the partition plate satisfy: S1≥0.5S2, where S1 is the sum of the cross-sectional areas of the through holes on the side of the partition plate facing the positive or negative electrode chamber, and S2 is the side area of ​​the partition plate facing the positive or negative electrode chamber.

6. A secondary battery according to claim 1, characterized in that, The diaphragm is made of multilayer polyethylene and / or polypropylene composite material, and the diaphragm has pores.

7. A secondary battery according to claim 6, characterized in that, The thickness of the diaphragm is 0.5 to 2 mm.

8. A secondary battery according to claim 1, characterized in that, The second current collector is located at the top of the lithium plate, with one end connected to the lithium plate and the other end connected to the negative electrode post.

9. A secondary battery according to claim 1, characterized in that, The lithium plate is provided in multiple ways, and the multiple lithium plates are spaced apart in the negative electrode chamber.

10. A secondary battery according to claim 1, characterized in that, The thickness of the lithium plate is 0.1 to 1 mm.

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