A laminated battery

Abstract

This utility model discloses a stacked battery, belonging to the field of battery technology. The stacked battery includes a positive electrode, a positive tab, a negative electrode, a first tab, and a second tab. The positive tab protrudes from the top side of the positive electrode and is coated with a first coating near the bottom of the positive electrode. The first and second tabs are spaced apart and protruding from the top side of the negative electrode. The positive electrode is stacked on one side of the negative electrode. The second tab is coated with a second coating, which is positioned opposite to the first coating. Along the thickness direction of the stacked battery, the projection of the first coating falls on the projection of the second coating. This stacked battery allows the second coating to completely cover the first coating, enabling the second coating to provide lithium-ion intercalation sites corresponding to the first coating. This avoids lithium plating problems caused by the lack of corresponding lithium-ion intercalation sites in the first coating and improves the overall capacity of the stacked battery.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, and in particular to a stacked battery. Background Technology

[0002] To further improve the energy density of stacked batteries, after coating the positive and negative electrodes (coating the empty foil area with an active material coating), the empty foil areas of the positive and negative electrodes without active material coating are cut to form tabs. In the process of die-cutting the positive tabs, a portion of the active material coating is usually left on the positive tabs to ensure that the die-cut positive tabs meet the requirements and to avoid side reactions between the positive tabs (aluminum foil) on the positive electrode and the electrolyte.

[0003] However, after the stacked battery is assembled, the active material coating on the positive electrode protrudes beyond the top of the negative electrode, making it impossible for the active material coating on the negative electrode to cover the active material coating on the positive electrode. Therefore, there is a risk of lithium plating, and the safety performance of the stacked battery cannot be guaranteed.

[0004] To address the above problems, a stacked battery technology is urgently needed. Utility Model Content

[0005] The purpose of this invention is to provide a stacked battery that can provide lithium-ion intercalation sites corresponding to the first coating through the second coating, so as to avoid lithium plating problems due to the lack of corresponding lithium-ion intercalation sites in the first coating, and to improve the overall capacity of the stacked battery.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] A stacked battery, comprising:

[0008] A positive electrode plate and a positive electrode tab, wherein the positive electrode tab protrudes from the top side of the positive electrode plate and a first coating is applied to the bottom of the positive electrode plate near the bottom of the positive electrode plate;

[0009] The battery comprises a negative electrode, a first tab, and a second tab. The first tab and the second tab are spaced apart and protrude from the top side of the negative electrode. The positive electrode is stacked on one side of the negative electrode. The second tab is coated with a second coating layer. The second coating layer is disposed opposite to the first coating layer, and along the thickness direction of the stacked battery, the projection of the first coating layer falls on the projection of the second coating layer.

[0010] As an alternative, along the first direction, the top surface of the positive electrode tab is flush with the top surface of the first electrode tab, the top surface of the second electrode tab is lower than the top surface of the positive electrode tab, and the first direction is parallel to the length direction of the stacked battery.

[0011] As an alternative, along the first direction, the ratio of the length of the positive electrode tab to the length of the first coating is l0:l1 = 1:(0.03~0.05).

[0012] Alternatively, along the second direction, the width of the first coating is equal to the width of the positive electrode tab, the second direction is perpendicular to the first direction, and the second direction is parallel to the width direction of the stacked battery.

[0013] As an alternative, the thickness of the first coating is less than 1 mm along the thickness direction of the stacked battery.

[0014] As an option, along the first direction, the length of the second coating is not less than the length of the first coating; along the second direction, the width of the second coating is not less than the width of the first coating.

[0015] As an alternative, along the first direction, the length of the second coating is 1 mm to 2 mm longer than the length of the first coating.

[0016] Alternatively, along the second direction, the width of the portion of the second coating extending beyond the opposite sides of the first coating area is the same.

[0017] Alternatively, along the first direction, the length of the second coating is equal to the length of the second tab; along the second direction, the width of the second coating is equal to the width of the second tab.

[0018] The beneficial effects of this utility model are as follows:

[0019] By attaching the positive tab to the top side of the positive electrode sheet and coating the bottom of the positive tab near the bottom of the positive electrode sheet with a first coating, that is, to prevent side reactions caused by exposed foil, a portion of the active material coating is left when the positive tab is die-cut on the positive electrode sheet. This active material coating is the first coating. At the same time, the first tab and the second tab are spaced apart and attached to the top side of the negative electrode sheet. A second coating is coated on the second tab and the second coating is positioned opposite to the first coating. Along the thickness direction of the stacked battery, the projection of the first coating falls on the projection of the second coating. That is, the second coating can completely cover the first coating, so that the second coating can provide lithium-ion intercalation sites corresponding to the first coating. This can avoid lithium plating problems caused by the lack of corresponding lithium-ion intercalation sites in the first coating, thus ensuring the safety performance of the entire stacked battery. Furthermore, since the lithium ions in the first coating can be intercalated into the lithium-ion intercalation sites on the second coating, the capacity of the entire stacked battery can be improved. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the stacked battery structure provided in this utility model;

[0021] Figure 2 This is a schematic diagram of the assembly structure between the positive electrode plate and the positive electrode tab provided in this utility model;

[0022] Figure 3 This is a schematic diagram of the assembly structure between the negative electrode sheet, the first electrode tab, and the second electrode tab provided in this utility model.

[0023] Explanation of reference numerals in the attached figures:

[0024] 10-Layer Cells;

[0025] 11-Positive electrode sheet; 12-Positive electrode tab; 13-First coating;

[0026] 21-Negative electrode; 22-First tab; 23-Second tab; 24-Second coating. Detailed Implementation

[0027] All features disclosed in this specification, or all steps in all disclosed methods or processes, may be combined in any way, except for mutually exclusive features and / or steps.

[0028] Any feature disclosed in this specification, unless specifically stated otherwise, may be replaced by other equivalent or similar features. That is, unless specifically stated otherwise, each feature is merely one example of a series of equivalent or similar features. Throughout this specification, the same reference numerals indicate the same elements.

[0029] To make the technical problem solved by this utility model, the technical solution adopted, and the technical effect achieved clearer, the technical solution of this utility model will be further described below with reference to the accompanying drawings and specific embodiments.

[0030] Currently, during the die-cutting process of forming the positive electrode tab, a portion of the active material coating is usually left on the positive electrode tab to ensure that the die-cut positive electrode tab meets the requirements and to avoid side reactions between the positive electrode tab (aluminum foil) on the positive electrode sheet and the electrolyte. However, after the stacked battery is assembled, the active material coating on the positive electrode tab protrudes beyond the top of the negative electrode sheet, making it impossible for the active material coating on the negative electrode sheet to cover the active material coating on the positive electrode tab. Therefore, there is a risk of lithium plating, and the safety performance of the stacked battery cannot be guaranteed.

[0031] Therefore, such as Figure 1As shown, this embodiment proposes a stacked battery 10, which can effectively avoid lithium plating problems, thus ensuring the overall safety performance of the stacked battery 10; furthermore, it can also improve the capacity of the stacked battery 10 to a certain extent. Specifically, the stacked battery 10 involved in this embodiment can be a square stacked battery 10. Here, the specific type of stacked battery 10 is not limited.

[0032] It is worth noting that the main improvement in this embodiment is to solve the lithium plating problem of the stacked battery 10 caused by the die-cut tabs. Here, the specific working principle of the stacked battery 10 will not be described in detail. You can refer to the working principle of the existing stacked battery 10.

[0033] Specifically, such as Figures 1 to 3 As shown, the stacked battery 10 includes a positive electrode 11, a positive tab 12, a negative electrode 21, a first tab 22, and a second tab 23. The positive tab 12 protrudes upward from the top side of the positive electrode 11, and a first coating 13 is coated on the positive tab 12 near the bottom of the positive electrode 11. The first tab 22 and the second tab 23 are spaced apart and protruding upward from the top side of the negative electrode 21. The positive electrode 11 is stacked on one side of the negative electrode 21 so that the positive tab 12 and the second tab 23 are opposite to each other. A second coating 24 is coated on the second tab 23. The second coating 24 is opposite to the first coating 13 on the positive tab 12, and the projection of the first coating 13 falls on the projection of the second coating 24 along the thickness direction of the stacked battery 10. That is, the second coating 24 can completely cover one side of the first coating 13.

[0034] By making the positive electrode tab 12 protrude onto the top side of the positive electrode plate 11, a first coating 13 is applied to the bottom of the positive electrode tab 12 near the positive electrode plate 11. That is, in order to prevent the exposure of the empty foil and the occurrence of side reactions, a part of the active material coating will remain when the positive electrode tab 12 is die-cut on the positive electrode plate 11. This active material coating is the first coating 13.

[0035] Compared with the prior art, the stacked battery 10 in this embodiment adds a second tab 23 at the corresponding position of the positive tab 12 and coats a second coating 24 at the corresponding position of the first coating 13. By coating the second coating 24 on the second tab 23 and setting the second coating 24 opposite to the first coating 13, and with the projection of the first coating 13 falling on the projection of the second coating 24 along the thickness direction of the stacked battery 10, that is, the second coating 24 can completely cover the first coating 13, so that the second coating 24 can provide lithium ion intercalation positions corresponding to the first coating 13, thereby avoiding lithium plating problems caused by the lack of corresponding lithium ion intercalation positions in the first coating 13, thus ensuring the safety performance of the entire stacked battery 10. Furthermore, since the lithium ions in the first coating 13 can be intercalated into the lithium ion intercalation positions on the second coating 24, the capacity of the entire stacked battery 10 can be improved.

[0036] Specifically, in this embodiment, by embedding the lithium ions of the first coating 13 into the lithium ion embedding positions on the second coating 24, the capacity of the entire stacked battery 10 can be increased by 1% compared to the case where the second tab 23 and the second coating 24 are not provided.

[0037] It is worth noting that, such as Figure 1 As shown, after stacking the positive electrode 11 and the negative electrode 21, a portion of the first coating 13 on the positive electrode tab 12 is positioned opposite to the negative electrode 21. That is, the lithium ions in this portion of the first coating 13 will be embedded into the lithium ion embedding positions on the negative electrode 21, thereby avoiding lithium plating problems and increasing the capacity of the stacked battery 10. The second coating 24 only needs to completely cover the portion of the first coating 13 that extends upward beyond the negative electrode 21.

[0038] Furthermore, such as Figure 1 As shown, along the first direction, the top surface of the positive electrode tab 12 is flush with the top surface of the first electrode tab 22, ensuring the normal operation of the positive electrode tab 12 and the first electrode tab 22 as the positive and negative current transmission channels of the entire stacked battery 10, thereby guaranteeing the normal current transmission performance of the entire stacked battery 10. The first direction is parallel to the length direction of the stacked battery 10, and the specific first direction is as follows... Figure 1 As shown by arrow A in the diagram.

[0039] Specifically, such as Figures 1 to 3As shown, along the first direction, the top surface of the second electrode 23 is lower than the top surface of the positive electrode 12, that is, the top surface of the second electrode 23 is lower than the top surface of the first electrode 22. On the one hand, this can avoid the waste of resources caused by setting a large area of ​​the second electrode 23, so as to save the cost of the stacked battery 10. On the other hand, it can avoid the impact on the normal use performance of the first electrode 22 and the positive electrode 12 due to the long setting length of the second electrode 23 in the first direction, so as to avoid the interference of the second electrode 23 on the first electrode 22 and the positive electrode 12.

[0040] Specifically, a positive electrode active material layer (such as lithium manganese oxide, lithium cobalt oxide, or a ternary material composed of oxides of nickel, cobalt, and manganese) is coated on an aluminum foil to form the aforementioned positive electrode sheet 11. Correspondingly, the first coating 13 on the positive electrode tab 12 can also be lithium manganese oxide, lithium cobalt oxide, or a ternary material composed of oxides of nickel, cobalt, and manganese.

[0041] Specifically, a negative electrode active material layer (such as layered graphite) is coated onto a copper foil to form the aforementioned negative electrode sheet 21. Correspondingly, the second coating layer 24 on the second tab 23 can also be layered graphite. Since the first tab 22 does not need to be coated with the second coating layer 24, that is, the first tab 22 is essentially a copper foil.

[0042] Furthermore, such as Figure 1 and Figure 2 As shown, along the first direction, the length ratio of the positive electrode tab 12 to the length of the first coating 13 is l0:l1 = 1:(0.03~0.05). That is, the coating length of the first coating 13 on the positive electrode tab 12 along the first direction is relatively short. This is to ensure that the positive electrode tab 12 that meets the requirements can be die-cut through the first coating 13, while minimizing the setting length of the first coating 13 in the first direction. This can correspondingly shorten the setting length of the second coating 24 in the first direction, thereby saving resources and better reducing the cost of the entire stacked battery 10.

[0043] Specifically, such as Figure 1 and Figure 2 As shown, along the second direction, the width of the first coating 13 is equal to the width of the positive electrode tab 12. On one hand, this avoids side reactions between the positive electrode tab 12 and the electrolyte near the bottom of the positive electrode sheet 11 due to incomplete coating with the first coating 13, ensuring that the die-cut positive electrode tab 12 meets requirements. On the other hand, it avoids the first coating 13 not completely covering the positive electrode tab 12 along the second direction due to its wider width, thus avoiding resource waste caused by the wider width of the positive electrode tab 12 in the second direction and further reducing the overall cost of the stacked battery 10. The second direction is perpendicular to the first direction and parallel to the width direction of the stacked battery 10. Specifically, the second direction is as follows: Figure 1 As shown by arrow B in the diagram.

[0044] Furthermore, along the thickness direction of the stacked battery 10, the thickness of the first coating 13 is less than 1 mm, so that the thickness of the first coating 13 is small, so that while ensuring that the positive electrode tab 12 that meets the requirements can be die-cut through the first coating 13, the lithium ions on the first coating 13 can be completely embedded into the lithium ion embedding positions on the second coating 24. This avoids the problem that the lithium ions on the first coating 13 are too numerous and cannot be completely embedded into the lithium ion embedding positions on the second coating 24, thereby better avoiding the lithium plating problem.

[0045] Specifically, such as Figures 1 to 3 As shown, along the first direction, the length of the second coating 24 is not less than the length of the first coating 13; along the second direction, the width of the second coating 24 is not less than the width of the first coating 13; that is, in both the first and second directions, the second coating 24 can completely cover the first coating 13, thereby ensuring that the projection of the first coating 13 can completely fall on the projection of the second coating 24 along the thickness direction of the stacked battery 10, thus effectively solving the lithium plating problem.

[0046] Furthermore, such as Figures 1 to 3 As shown, along the first direction, the length of the second coating 24 is 1 mm to 2 mm longer than the length of the first coating 13, so that the length of the second coating 24 in the first direction is slightly greater than the length of the first coating 13 in the first direction. This is to save coating resources of the second coating 24 while ensuring that the second coating 24 can provide sufficient lithium ion insertion sites, thereby ensuring that the lithium ions of the first coating 13 can be completely inserted into the lithium ion insertion sites on the second coating 24.

[0047] Specifically, such as Figures 1 to 3 As shown, along the second direction, the width of the portion of the second coating 24 extending beyond the opposite sides of the first coating 13 region is the same; on the one hand, it can better ensure that the second coating 24 provides sufficient lithium ion insertion positions, and further ensure that the lithium ions of the first coating 13 can be completely inserted into the lithium ion insertion positions on the second coating 24; on the other hand, it can facilitate the coating of the second coating 24, making the coating of the second coating 24 on the second tab 23 simpler and more convenient.

[0048] Furthermore, such as Figures 1 to 3As shown, along the first direction, the length of the second coating 24 is equal to the length of the second tab 23; along the second direction, the width of the second coating 24 is equal to the width of the second tab 23; that is, in both the first and second directions, the second coating 24 completely covers the second tab 23. On the one hand, this facilitates the coating of the second coating 24 onto the second tab 23, making the coating of the second coating 24 simpler and more convenient; on the other hand, it avoids resource waste caused by the second tab 23 being too large in both the first and second directions, and can further reduce the cost of the entire stacked battery 10.

[0049] In one embodiment, the stacked battery 10 further includes a separator disposed between the positive electrode 11 and the negative electrode 21, so as to separate the positive electrode 11 and the negative electrode 21 through the separator, and the separator can also separate the second tab 23 and the positive tab 12. Here, the separator can adopt a separator structure commonly used in existing batteries.

[0050] In other embodiments, the stacked battery 10 may also include a solid electrolyte membrane disposed between the positive electrode 11 and the negative electrode 21, so as to separate the positive electrode 11 and the negative electrode 21 by means of the solid electrolyte membrane, and the solid electrolyte membrane can also separate the second tab 23 and the positive tab 12. Here, the solid electrolyte membrane can adopt the solid electrolyte membrane structure commonly used in existing batteries.

[0051] It is worth noting that the first coating 13 can be applied to one side of the positive electrode tab 12 or to the opposite two sides of the positive electrode tab 12; correspondingly, the second coating 24 can be applied to one side of the second electrode tab 23 or to the opposite two sides of the second electrode tab 23. The specific coating method needs to be determined according to the actual number and stacking arrangement of the positive electrode sheet 11 and the negative electrode sheet 21, as long as it is ensured that in adjacent positive electrode sheets 11 and negative electrode sheets 21, the second coating 24 on the second electrode tab 23 can relatively and completely cover the first coating 13 on the positive electrode tab 12.

[0052] In this embodiment, the stacked battery 10 has a second tab 23 protruding on one side of the negative electrode 21, and a second coating 24 is coated on the second tab 23, so that the second coating 24 can completely cover the first coating 13. This can effectively solve the problem of lithium plating on the first coating 13 on the positive tab 12; at the same time, it can increase the capacity of the entire stacked battery 10 by 1%.

[0053] In this embodiment, the stacked battery 10 has the following characteristics: along the first direction, the ratio of the length of the positive electrode tab 12 to the length of the first coating 13 is l0:l1 = 1:(0.03~0.05); along the second direction, the width of the first coating 13 is equal to the width of the positive electrode tab 12; along the thickness direction of the stacked battery 10, the thickness of the first coating 13 is less than 1mm; along the first direction, the length of the second coating 24 is not less than the length of the first coating 13; along the second direction, the width of the second coating 24 is not less than the width of the first coating 13; along the first direction, the length of the second coating 24 is 1mm~2mm greater than the length of the first coating 13; along the second direction... The second coating 24 extends to the same width on both sides of the first coating 13 region; along the first direction, the length of the second coating 24 is equal to the length of the second tab 23; along the second direction, the width of the second coating 24 is equal to the width of the second tab 23; thus, the coating of the first coating 13 and the second coating 24 can be made convenient; and the size of the positive tab 12, the second tab 23, the first coating 13 and the second coating 24 can be reduced, thereby saving resources and reducing costs; at the same time, it ensures that the lithium ions on the first coating 13 can be completely embedded into the lithium ion embedding positions on the second coating 24, thus effectively solving the lithium plating problem.

[0054] The above description is only a preferred embodiment of this utility model. For those skilled in the art, there will be changes in the specific implementation method and application scope based on the idea of ​​this utility model. The content of this specification should not be construed as a limitation of this utility model.

Claims

1. A stacked battery, characterized by, include: A positive electrode plate (11) and a positive electrode tab (12), wherein the positive electrode tab (12) protrudes from the top side of the positive electrode plate (11), and the positive electrode tab (12) is coated with a first coating layer (13) near the bottom of the positive electrode plate (11); The negative electrode (21), the first tab (22) and the second tab (23) are spaced apart and protrude from the top side of the negative electrode (21). The positive electrode (11) is stacked on one side of the negative electrode (21). The second tab (23) is coated with a second coating (24). The second coating (24) is disposed opposite to the first coating (13). Along the thickness direction of the stacked battery, the projection of the first coating (13) falls on the projection of the second coating (24).

2. The stack battery of claim 1, wherein, Along the first direction, the top surface of the positive electrode tab (12) is flush with the top surface of the first electrode tab (22), and the top surface of the second electrode tab (23) is lower than the top surface of the positive electrode tab (12). The first direction is parallel to the length direction of the stacked battery.

3. The stack battery of claim 1, wherein, Along the first direction, the length ratio of the positive electrode tab (12) to the length of the first coating (13) is l0:l1 = 1:(0.03~0.05).

4. The stacked battery of claim 3, wherein Along the second direction, the width of the first coating (13) is equal to the width of the positive electrode tab (12), the second direction is perpendicular to the first direction, and the second direction is parallel to the width direction of the stacked battery.

5. The stacked battery of any one of claims 1-4, wherein, Along the thickness direction of the stacked battery, the thickness of the first coating (13) is less than 1 mm.

6. The stacked battery of any one of claims 1-4, wherein, Along the first direction, the length of the second coating (24) is not less than the length of the first coating (13); along the second direction, the width of the second coating (24) is not less than the width of the first coating (13).

7. The stacked battery of claim 6, wherein Along the first direction, the length of the second coating (24) is 1 mm to 2 mm longer than the length of the first coating (13).

8. The stacked battery of claim 6, wherein, Along the second direction, the width of the portion of the second coating (24) extending beyond the opposite sides of the first coating (13) region is the same.

9. The stacked battery of any one of claims 1-4, wherein, Along the first direction, the length of the second coating (24) is equal to the length of the second tab (23); along the second direction, the width of the second coating (24) is equal to the width of the second tab (23).

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