Positive electrode structure of battery cell

Abstract

The utility model discloses a positive pole structure of a battery cell. The positive pole structure of the battery cell comprises a positive pole piece and a negative pole piece, the insulating heat-resistant layer is arranged on the first side of the positive pole piece; the ceramic coating is coated on a second side, opposite to the first side, of the positive pole piece; and the positive pole lug is arranged on one side, far away from the positive pole piece, of the ceramic coating. The positive electrode structure of the battery cell disclosed by the utility model is used for solving the problem that the short circuit risk exists in the battery cell due to the design of the battery cell in the prior art.

Description

Technical Field

[0001] The utility model belongs to the technical field of lithium batteries, and particularly relates to a positive electrode structure of a battery cell. Background Art

[0002] When manufacturing a battery cell in the lithium-ion battery manufacturing industry, during the winding process, the positive and negative electrode plates are wound separately through a separator film (hereinafter referred to as the separator) to isolate the positive and negative electrode plates and prevent short circuit between the positive and negative electrode plates.

[0003] However, when the temperature of the battery cell is too high, the separator will shrink, resulting in contact between the bottom of the positive electrode and the negative electrode. The contact between the positive and negative electrode plates will cause an internal short circuit of the battery cell, seriously affecting the product safety. Summary of the Utility Model

[0004] The utility model provides a positive electrode structure of a battery cell to solve the problem that the design of the existing battery cell has a risk of internal short circuit.

[0005] To solve the above technical problems, the utility model provides a positive electrode structure of a battery cell, which includes:

[0006] A positive electrode plate;

[0007] An insulating and heat-resistant layer, which is arranged on the first side of the positive electrode plate;

[0008] A ceramic coating, which is coated on the second side of the positive electrode plate opposite to the first side;

[0009] And a positive electrode tab, which is arranged on the side of the ceramic coating away from the positive electrode plate.

[0010] Optionally, the shrinkage temperature of the insulating and heat-resistant layer is greater than 130 degrees Celsius.

[0011] Optionally, the strength of the insulating and heat-resistant layer is greater than the strength of the burrs on the first side of the positive electrode plate.

[0012] Optionally, the insulating and heat-resistant layer is made of ceramic material.

[0013] Optionally, the insulating and heat-resistant layer covers the second side of the positive electrode plate.

[0014] Optionally, the coating thickness of the insulating and heat-resistant layer is greater than 2 mm.

[0015] Optionally, the coating thickness of the insulating and heat-resistant layer is greater than 2 mm and less than 3 mm.

[0016] Optionally, the ceramic coating covers the first side of the positive electrode plate.

[0017] Optionally, the coating thickness of the ceramic coating is greater than 2 mm.

[0018] Optionally, the coating thickness of the ceramic coating is greater than 2 mm and less than 3 mm.

[0019] Compared with the prior art, a positive electrode structure of a battery cell provided by the present utility model has the following beneficial effects:

[0020] The top of the positive electrode plate of the battery cell is close to one side of the positive electrode tab of the battery cell, and the positive electrode tab is arranged on the ceramic coating located on the second side of the positive electrode plate. Therefore, the second side of the positive electrode plate is the top of the positive electrode plate. Since the second side of the positive electrode plate is the top of the positive electrode plate, the first side opposite to the second side of the positive electrode plate is the bottom of the positive electrode plate. The bottom of the positive electrode plate and the negative electrode plate are separated by a separator. Therefore, arranging an insulating and heat-resistant layer on the first side of the positive electrode plate can prevent the insulating and heat-resistant layer from shrinking when the temperature of the battery cell is too high. In this way, even if the separator shrinks when the battery cell generates heat, the insulating and heat-resistant layer can compensate for the shrinkage loss of the separator, so that the positive electrode plate will not contact the negative electrode plate, causing an internal short circuit in the battery cell. Description of the Drawings

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only a part of the embodiments of the present utility model, rather than all the embodiments. For those of ordinary skill in the art, without creative efforts, other drawings obtained based on these drawings all belong to the scope of protection of the present utility model.

[0022] Figure 1 is a three-dimensional structure diagram of a positive electrode structure of a battery cell provided by an embodiment of the present utility model;

[0023] Figure 2 is an exploded view of a positive electrode structure of a battery cell provided by an embodiment of the present utility model in a certain direction.

[0024] Description of the reference numerals: 100 - positive electrode plate, 200 - insulating and heat-resistant layer, 300 - ceramic coating, 400 - positive electrode tab, 500 - separator, 600 - negative electrode plate, 610 - negative electrode tab. Detailed Embodiments

[0025] In order to make the purpose, technical solutions and advantages of the present utility model clearer, the following will further describe the present utility model in detail with reference to the drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present utility model, rather than to limit the present utility model.

[0026] To make the description of the present disclosure more detailed and complete, the following provides an illustrative description of the embodiments and specific examples of the present invention; however, this is not the only form for implementing or applying the specific examples of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

[0027] It should be noted that the terms "first", "second", etc. in the specification, claims and above-mentioned drawings of the present invention are used to distinguish similar objects and do not necessarily describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein.

[0028] In the description of the embodiments of the present invention, "a plurality" means two or more, and other quantifiers are similar. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention and do not limit the present invention. And without conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other.

[0029] As Figure 1 shown is a three-dimensional structure diagram of a positive electrode structure of a battery cell provided by an embodiment of the present invention. As Figure 2 shown is an exploded view of a positive electrode structure of a battery cell provided by an embodiment of the present invention in a certain direction. The positive electrode structure includes: a positive electrode tab 100; an insulating heat-resistant layer 200, the insulating heat-resistant layer 200 is disposed on a first side of the positive electrode tab 100; a ceramic coating 300, the ceramic coating 300 is coated on a second side of the positive electrode tab 100 opposite to the first side; and a positive electrode ear 400, the positive electrode ear 400 is disposed on a side of the ceramic coating 300 away from the positive electrode tab 100.

[0030] It should be noted that the insulating heat-resistant layer 200 can be any coating having insulation and heat resistance, and no detailed limitation is provided herein.

[0031] It should be noted that the thickness of the insulating heat-resistant layer 200 can be greater than a preset threshold value to ensure that when the separator 500 between the positive electrode and the negative electrode shrinks, the insulating heat-resistant layer 200 can fully separate the positive electrode and the negative electrode.

[0032] It can be understood that setting the ceramic coating 300 on the second side of the positive electrode tab 100 can have the following advantages:

[0033] 1. Improve the stability of battery performance: The ceramic coating 300 can enhance the structural stability of the positive electrode material, enabling it to withstand higher voltages and currents, and improving the cycle life of the battery. In addition, the ceramic coating 300 can also reduce the mutual reaction between the positive electrode material and the electrolyte, avoiding the loss of the electrolyte and the damage to the electrode surface, thereby improving the performance stability of the battery.

[0034] 2. Increase the energy density of the battery: The ceramic coating 300 can increase the charge conduction ability of the positive electrode material, reduce the internal resistance of the electrode, and increase the energy density of the battery. The ceramic coating 300 can increase the specific surface area of the electrode, increase the reaction contact area of electrons and ions, and promote the progress of the electrochemical reaction, thereby increasing the energy density of the battery.

[0035] 3. Improve the safety of the battery: The ceramic coating 300 has high thermal stability and corrosion resistance, can effectively prevent the degradation and dissolution of the battery positive electrode material, and effectively prevent the short circuit of the positive and negative electrodes caused by the shrinkage of the separator 500 at high temperature, reducing the risk of thermal runaway and combustion of the battery. In addition, the ceramic coating 300 can also reduce the self-discharge rate of the battery, extend the life of the battery, and improve the safety performance of the battery.

[0036] The top of the positive electrode plate 100 of the battery cell is close to one side of the positive electrode tab 400 of the battery cell, and the positive electrode tab 400 is arranged on the ceramic coating 300 located on the second side of the positive electrode plate 100. Therefore, the second side of the positive electrode plate 100 is the top of the positive electrode plate 100. The second side of the positive electrode plate 100 is the top of the positive electrode plate 100. Therefore, the first side opposite to the second side of the positive electrode plate 100 is the bottom of the positive electrode plate 100. The bottom of the positive electrode plate 100 and the negative electrode plate 600 are separated by a separator 500. Therefore, setting the insulating and heat-resistant layer 200 on the first side of the positive electrode plate 100 can prevent the insulating and heat-resistant layer 200 from shrinking when the temperature of the battery cell is too high. In this way, even if the separator 500 shrinks when the battery cell heats up, the insulating and heat-resistant layer 200 can compensate for the shrinkage loss of the separator 500, so that the positive electrode plate 100 will not contact the negative electrode plate 600, and no internal short circuit of the battery cell will occur.

[0037] It should be noted that, as Figure 1 and Figure 2 shown, on one side of the negative electrode plate 600 of the battery cell, a negative electrode tab 610 is also provided.

[0038] In an optional implementation manner, the shrinkage temperature of the insulating and heat-resistant layer 200 is greater than 130 degrees Celsius.

[0039] It should be noted that the separator 500 usually shrinks when the temperature of the battery cell is greater than 130 degrees Celsius. Therefore, the shrinkage temperature of the insulation and heat-resistant layer 200 is greater than 130 degrees Celsius, which can prevent the insulation and heat-insulating layer 200 from shrinking when the temperature is greater than 130 degrees Celsius. Thus, when the separator 500 shrinks, the insulation and heat-resistant layer 200 can separate the positive electrode plate 100 from the negative electrode plate 600 instead of the separator 500.

[0040] It should be noted that the insulation and heat-resistant layer 200 can be any coating with insulation properties and a shrinkage temperature greater than 130 degrees Celsius.

[0041] In an optional implementation, the strength of the insulation and heat-resistant layer 200 is greater than the strength of the burrs on the first side of the positive electrode plate 100.

[0042] It can be understood that burrs are usually generated at the bottom (i.e., the first side) of the positive electrode plate 100 during die-cutting. The burrs at the bottom of the positive electrode plate 100 can pierce the separator 500, resulting in a short circuit between the positive electrode plate 100 and the negative electrode plate 600. Therefore, in this implementation, making the strength of the insulation and heat-resistant layer 200 greater than the strength of the burrs on the first side of the positive electrode plate 100 can ensure that when the separator 500 is pierced by the burrs, the insulation and heat-resistant layer 200 can separate the positive electrode plate 100 from the negative electrode plate 600 instead of the separator 500, preventing a short circuit between the positive electrode plate 100 and the negative electrode plate 600.

[0043] In an optional implementation, the insulation and heat-resistant layer 200 is made of ceramic material.

[0044] It can be understood that ceramics can improve the performance stability of the battery: ceramics can enhance the structural stability of the positive electrode material, enabling it to withstand higher voltages and currents, and improving the cycle life of the battery; in addition, ceramics can also reduce the interaction between the positive electrode material and the electrolyte: avoiding the loss of the electrolyte and the damage of the electrode surface, thereby improving the performance stability of the battery; it can also improve the energy density of the battery: ceramics can increase the charge conduction ability of the positive electrode material, reduce the internal resistance of the electrode, and improve the energy density of the battery. Ceramics can increase the specific surface area of the electrode, increase the reaction contact area of electrons and ions, and promote the progress of the electrochemical reaction, thereby improving the energy density of the battery; and improve the safety of the battery: ceramics have high thermal stability and corrosion resistance, can effectively prevent the degradation and dissolution of the battery positive electrode material, and can effectively prevent the short circuit between the positive and negative electrodes caused by the shrinkage of the separator 500 at high temperature, reducing the risk of thermal runaway and combustion of the battery. In addition, ceramics can also reduce the self-discharge rate of the battery, extend the life of the battery, and improve the safety performance of the battery. Therefore, when the insulation and heat-resistant layer 200 on the second side of the positive electrode plate 100 is made of ceramic material, the problem of short circuit between the positive electrode plate 100 and the negative electrode plate 600 caused by the shrinkage of the separator 500 can be avoided.

[0045] In an alternative implementation, as Figure 1 and Figure 2 shown, the insulating and heat-resistant layer 200 covers the second side of the positive electrode plate 100.

[0046] It can be understood that covering the second side of the positive electrode plate 100 with the insulating and heat-insulating layer 200 can prevent the second side of the positive electrode plate 100 from coming into contact with the negative electrode plate 600 when the separator 500 shrinks, thus effectively avoiding short-circuiting between the positive electrode plate 100 and the negative electrode plate 600.

[0047] In an alternative implementation, the coating thickness of the insulating and heat-resistant layer 200 is greater than 2 mm.

[0048] It can be understood that the longitudinal shrinkage of the separator 500 is usually about 4%. The normal width of the separator 500 is 6 - 7 mm longer than the width of the positive electrode plate in the width direction. Assuming the width of the separator 500 is 196.5 mm and the positive electrode is 190 mm, the shrinkage length of the separator 500, which is 196.5 mm multiplied by 4%, equals 7.86 mm. The separator 500 is 6.5 mm wider than the positive electrode (196.5 mm minus 190 mm). The width of the insulating and heat-resistant layer 200 is greater than 2 mm. The sum of the width of the separator 500 in contact with the positive electrode material area, which is 6.5 mm, and the thickness of the insulating and heat-resistant layer 200, which is 2 mm, is greater than 7.86 mm, thus preventing short-circuiting between the positive and negative electrodes. Therefore, when the coating thickness of the insulating and heat-resistant layer 200 is greater than 2 mm, short-circuiting between the positive and negative electrodes can be effectively avoided.

[0049] In an alternative implementation, the coating thickness of the insulating and heat-resistant layer 200 is greater than 2 mm and less than 3 mm.

[0050] It can be understood that the thicker the coating thickness of the insulating and heat-insulating layer 200, the better the effect of preventing short-circuiting between the positive and negative electrodes. However, too much material is used for the insulating and heat-resistant layer 200. On the one hand, it causes the volume of the battery cell to be too large, making it inconvenient for the battery cell to be designed for handling. On the other hand, it increases the material cost of the battery cell. Therefore, setting the coating thickness of the insulating and heat-resistant layer 200 to be greater than 2 mm and less than 3 mm can save materials to a certain extent while ensuring the isolation of short-circuiting between the positive and negative electrodes, facilitating the handling design.

[0051] In an alternative implementation, as Figure 1 and Figure 2 shown, the ceramic coating 300 covers the first side of the positive electrode plate 100.

[0052] It can be understood that covering the second side of the positive electrode plate 100 with the ceramic coating 300 can prevent the second side of the positive electrode plate 100 from coming into contact with the negative electrode plate 600 when the separator 500 shrinks, thus effectively avoiding short-circuiting between the positive electrode plate 100 and the negative electrode plate 600.

[0053] In an alternative implementation, the coating thickness of the ceramic coating 300 is greater than 2 mm.

[0054] It can be understood that the longitudinal shrinkage of the separator 500 is generally about 4%. The normal width of the separator 500 is 6 - 7 mm longer than the width direction of the positive electrode tab. Assuming the width of the separator 500 is 196.5 mm and the positive electrode is 190 mm, the shrinkage length of the separator 500, which is the product of 196.5 mm and 4%, equals 7.86 mm. The separator 500 is 6.5 mm wider than the positive electrode (196.5 mm minus 190 mm). The width of the ceramic coating 300 is greater than 2 mm. The sum of the width of the separator 500 in contact with the positive electrode material area, which is 6.5 mm, and the thickness of the insulating and heat-resistant layer 200, which is 2 mm, is greater than 7.86 mm, thereby preventing the positive electrode and the negative electrode from short-circuiting. Therefore, when the coating thickness of the insulating and heat-resistant layer 200 is greater than 2 mm, the short-circuiting between the positive electrode and the negative electrode can be effectively avoided.

[0055] In an alternative implementation, the coating thickness of the ceramic coating 300 is greater than 2 mm and less than 3 mm.

[0056] It can be understood that the thicker the coating thickness of the insulating and heat-resistant layer 200, the better the effect of preventing the positive electrode and the negative electrode from short-circuiting. However, too much material is used for the insulating and heat-resistant layer 200. On the one hand, it causes the volume of the battery cell to be too large, making it inconvenient for the battery cell to be designed for handling. On the other hand, it increases the material cost of the battery cell. Therefore, setting the coating thickness of the insulating and heat-resistant layer 200 to be greater than 2 mm and less than 3 mm can save materials to a certain extent while ensuring the isolation of the positive and negative electrodes from short-circuiting, which is convenient for handling design.

[0057] The technical solutions provided by the present utility model have been introduced in detail above. Specific examples are used in the present utility model to elaborate on the principle and implementation manner of the present utility model. The description of the above embodiments is only used to help understand the structure and core idea of the present utility model; at the same time, for those of ordinary skill in the art, according to the idea of the present utility model, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present utility model.

[0058] Obviously, those skilled in the art can make various modifications and variations to the present utility model without departing from the spirit and scope of the present utility model. Thus, if these modifications and variations of the present utility model fall within the scope of the claims of the present utility model and their equivalent technologies, the present utility model also intends to include these modifications and variations.

Claims

1. A positive electrode structure of a battery cell, characterized in that: include: Positive electrode; An insulating heat-resistant layer, the insulating heat-resistant layer being disposed on a first side of the positive electrode plate; A ceramic coating, the ceramic coating being applied to a second side of the positive electrode sheet opposite to the first side; And a positive electrode tab, wherein the positive electrode tab is arranged on a side of the ceramic coating away from the positive electrode sheet.

2. The positive electrode structure of the battery cell according to claim 1, characterized in that: The shrinkage temperature of the insulating heat-resistant layer is greater than 130 degrees Celsius.

3. The positive electrode structure of the battery cell according to claim 2, characterized in that: The strength of the insulating heat-resistant layer is greater than the strength of the burrs on the first side of the positive electrode sheet.

4. The positive electrode structure of the battery cell according to claim 3, characterized in that: The insulating heat-resistant layer is made of ceramic material.

5. The positive electrode structure of the battery cell according to claim 4, characterized in that: The insulating heat-resistant layer covers the second side of the positive electrode sheet.

6. The positive electrode structure of the battery cell according to claim 5, characterized in that: The coating thickness of the insulating heat-resistant layer is greater than 2 mm.

7. The positive electrode structure of the battery cell according to claim 6, characterized in that: The coating thickness of the insulating heat-resistant layer is greater than 2 mm and less than 3 mm.

8. The positive electrode structure of the battery cell according to claim 1, characterized in that: The ceramic coating covers the first side of the positive electrode sheet.

9. The positive electrode structure of the battery cell according to claim 8, characterized in that: The coating thickness of the ceramic coating is greater than 2 mm.

10. The positive electrode structure of the battery cell according to claim 9, characterized in that: The coating thickness of the ceramic coating is greater than 2 mm and less than 3 mm.

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