Diaphragm structure, battery cell, battery module and vehicle

Abstract

The application relates to the technical field of batteries, in particular to a diaphragm structure, a battery cell, a battery module and a vehicle. The diaphragm structure comprises a diaphragm body, the diaphragm body is clamped between a positive pole piece and a negative pole piece; a blocking piece is made of an insulating material, the blocking piece is fixedly arranged on one side of the diaphragm body facing the negative pole piece, and the blocking piece is located at a first end of the negative pole piece; one end of the positive pole piece with a positive pole lug is located on the same side as the first end of the negative pole piece; and the blocking piece can block the positive pole lug from contacting the first end of the negative pole piece. The application can reduce the risk of the positive pole lug being inserted into the negative pole piece reversely, and can inhibit the lithium precipitation phenomenon.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and more particularly to a separator structure, a battery cell, a battery module, and a vehicle. Background Technology

[0002] With the development of new energy sources, more and more lithium-ion batteries are being used in production and daily life. During operation, lithium-ion batteries are prone to safety accidents due to thermal runaway, which is mainly caused by internal short circuits. Among these, the common form of internal short circuit is the reverse insertion of the tabs into the electrode plates due to redundant tab design and manufacturing issues.

[0003] like Figures 1-2 As shown, during the cell manufacturing process, the edge of the positive electrode plate 2 with the positive electrode tab 21 is usually provided with an insulating coating 22, which can effectively prevent the negative electrode tab 31 from being inserted into the positive electrode plate 2 and causing a short circuit. However, there is a lack of safety redundancy design for the positive electrode tab 21 being inserted into the negative electrode plate 3. Figure 2 As shown, there is a risk that the positive electrode tab 21 may be inserted backwards into the negative electrode 3, causing a short circuit and triggering thermal runaway. In addition, since lithium may be deposited at the edge of the negative electrode 3 during the use of lithium-ion batteries, the lithium deposits crossing the separator also pose a risk of short circuit.

[0004] Therefore, a membrane structure, battery cell, battery module, and vehicle are needed to solve the above problems. Summary of the Invention

[0005] The purpose of this invention is to provide a separator structure, a battery cell, a battery module, and a vehicle that can reduce the risk of the positive electrode tab being inserted backwards into the negative electrode sheet and can suppress lithium plating.

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

[0007] The diaphragm structure includes:

[0008] A diaphragm body, wherein the diaphragm body is sandwiched between the positive electrode and the negative electrode;

[0009] The blocking element is made of insulating material and is fixedly disposed on the side of the diaphragm body facing the negative electrode sheet. The blocking element is located at the first end of the negative electrode sheet, and the first end is on the same side as the end of the positive electrode sheet with the positive electrode tab. The blocking element can prevent the positive electrode tab from contacting the first end of the negative electrode sheet.

[0010] In some embodiments, the diaphragm body is coated with adhesive on the side facing the negative electrode, and the blocking member is bonded to the diaphragm body by the adhesive.

[0011] In some embodiments, the material of the blocking member is one or a mixture of several of polyimide, Teflon, glass fiber, and silicone.

[0012] In some embodiments, the adhesive is made of one or a mixture of natural rubber, synthetic rubber, silicone, and polyurethane.

[0013] In some embodiments, the height of the adhesive ranges from 0.1 mm to 10 mm.

[0014] In some embodiments, the thickness of the blocking element ranges from 1µm to 1000µm.

[0015] In some embodiments, the blocking member completely covers the end of the negative electrode sheet.

[0016] The battery cell includes a positive electrode, a negative electrode, and a separator structure as described above, wherein the separator structure is sandwiched between the positive electrode and the negative electrode.

[0017] The battery module includes multiple sets of battery cells as described above, which are connected in series or in parallel.

[0018] Vehicles, including the battery module as described above.

[0019] The beneficial effects of this invention are:

[0020] The present invention provides a diaphragm structure in which the diaphragm body is sandwiched between the positive electrode and the negative electrode. A blocking member made of insulating material is fixedly disposed on the side of the diaphragm body facing the negative electrode, and the blocking member is located at the first end of the negative electrode, which is on the same side as the end of the positive electrode with the positive electrode tab. Through this arrangement, the blocking member provides insulation protection to the end of the negative electrode, preventing the positive electrode tab from being inserted into the negative electrode, thereby reducing the risk of the positive electrode tab being inserted backwards into the negative electrode. Furthermore, due to the insulating properties of the blocking member, lithium plating can be suppressed, further reducing the risk of internal short circuits within the battery cell.

[0021] The present invention provides a battery cell comprising a positive electrode and a negative electrode as described above, and a separator structure that can reduce the risk of the positive electrode tab being inserted backwards into the negative electrode and can suppress lithium plating, thereby reducing the risk of internal short circuits in the battery cell.

[0022] The present invention provides a battery module comprising multiple sets of cells as described above, which can reduce the risk of the positive electrode tab being inserted backwards into the negative electrode plate and can suppress lithium plating, thereby reducing the risk of internal short circuits in the cells.

[0023] The present invention provides a vehicle comprising the battery module as described above, which can reduce the risk of the positive electrode tab being inserted backwards into the negative electrode plate and can suppress lithium plating, thereby reducing the risk of internal short circuits in the battery cell. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the content of the embodiments of the present invention and these drawings without creative effort.

[0025] Figure 1 This is a cross-sectional view of a battery cell in the existing technology;

[0026] Figure 2 This is another cross-sectional view of a battery cell in the existing technology;

[0027] Figure 3 This is a cross-sectional view of a battery cell according to the present invention.

[0028] In the picture:

[0029] 1. Diaphragm body; 2. Positive electrode plate; 21. Positive electrode tab; 22. Insulating coating; 3. Negative electrode plate; 31. Negative electrode tab; 4. Blocking component. Detailed Implementation

[0030] Before explaining any embodiments of the invention in detail, it should be understood that the invention is not limited to its application to the structural details and component arrangements set forth in the following description or shown in the accompanying drawings.

[0031] In this invention, the terms "comprising," "including," "having," or any other variations thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0032] In this invention, the terms "connection," "combination," and "installation" can refer to direct connection, combination, or installation, or indirect connection, combination, or installation. For example, a direct connection refers to two parts or components being connected together without the need for an intermediary, while an indirect connection refers to two parts or components each being connected to at least one intermediary, with the connection achieved through the intermediary.

[0033] In this invention, those skilled in the art will understand that the function performed by a component can be performed by one component, multiple components, one part, or multiple parts. Similarly, the function performed by a part can also be performed by one part, one component, or a combination of multiple parts.

[0034] In this invention, the directional terms "upper," "lower," "left," "right," "front," and "rear" are used to describe the orientation and positional relationships shown in the accompanying drawings and should not be construed as limiting the embodiments of this invention. Furthermore, in the context, it should be understood that when an element is mentioned as being connected "upper" or "lower" to another element, it can be directly connected to the other element "upper" or "lower," or indirectly connected through an intermediate element. It should also be understood that directional terms such as upper side, lower side, left side, right side, front side, and rear side not only represent positive orientation but can also be understood as lateral orientation. For example, "below" can include directly below, lower left, lower right, lower front, and lower rear.

[0035] Lithium-ion batteries play a vital role in daily life and production. In new energy vehicles, lithium-ion batteries are the core power source, their high energy density and fast charging capabilities meeting range requirements. They are also used in equipment such as electric drills and cutting machines, where high power density and rapid discharge characteristics improve work efficiency. Mobile phones, laptops, and tablets rely on lithium-ion batteries to achieve miniaturization and weight reduction. However, lithium-ion batteries suffer from several manufacturing issues. For example, the positive electrode tab may be inserted backwards into the negative electrode, causing an internal short circuit. Furthermore, lithium plating may occur at the edge of the negative electrode during use, potentially leading to short circuits and, due to thermal runaway, safety accidents.

[0036] In the design and manufacture of lithium-ion batteries, to address the aforementioned problems, thereby reducing the risk of the positive electrode tab being inserted backwards into the negative electrode, and suppressing lithium plating, this invention provides a separator structure. For example... Figure 3 As shown, the diaphragm structure includes a diaphragm body 1 and a blocking element 4.

[0037] The diaphragm body 1 is sandwiched between the positive electrode 2 and the negative electrode 3, with the edge of the diaphragm body 1 extending outwards from the positive electrode 2 and the negative electrode 3. The blocking member 4 is made of insulating material and is fixedly disposed on the side of the diaphragm body 1 facing the negative electrode 3. The blocking member 4 is located at the first end of the negative electrode 3, and the first end is on the same side as the end of the positive electrode 2 with the positive electrode tab 21. The blocking member 4 can prevent the positive electrode tab 21 from contacting the first end of the negative electrode 3.

[0038] By fixing a blocking member 4 at the edge of the diaphragm body 1, the blocking member 4 provides insulation protection for the end of the negative electrode plate 3, thereby preventing the positive electrode tab 21 from being inserted into the negative electrode plate 3, thus reducing the risk of the positive electrode tab 21 being inserted backwards into the negative electrode plate 3. Moreover, due to the insulating properties of the blocking member 4, lithium plating can be suppressed, thereby further reducing the risk of internal short circuits in the battery cell.

[0039] In some embodiments, the projection of the blocking member 4 along the direction perpendicular to the positive electrode plate 2 at least partially coincides with the positive electrode tab 21, and the length of the overlap is not less than the length of the positive electrode tab 21. For example... Figure 3 As shown, the length of the positive electrode tab 21 refers to its length perpendicular to the plane of the paper. This design effectively prevents the positive electrode tab 21 from being inserted backwards into the negative electrode plate 3, thus preventing the positive electrode tab 21 from contacting the first end of the negative electrode plate 3.

[0040] In some embodiments, the positive electrode 2 is formed by coating both sides of the current collector with a positive active material (such as lithium iron phosphate, lithium cobalt oxide, or lithium manganese oxide), and the current collector is typically aluminum foil (requiring high oxidation resistance). The negative electrode 3 is formed by coating both sides of the current collector with a negative active material (graphite, silicon-based composite material, or lithium titanate), and the current collector is typically copper foil (offering better conductivity).

[0041] In some embodiments, adhesive is applied to the side of the diaphragm body 1 facing the negative electrode 3, and the blocking member 4 is bonded to the diaphragm body 1 by the adhesive. By fixing the blocking member 4 with adhesive, a stable connection between the blocking member 4 and the diaphragm body 1 can be ensured. Moreover, installing the blocking member 4 with adhesive does not require changing the original manufacturing process of the diaphragm, thereby reducing the impact on the existing manufacturing process.

[0042] In some embodiments, the blocking element 4 is made of one or a mixture of polyimide, Teflon, glass fiber, and silicone. The blocking element 4, made of one or a mixture of these materials, has good insulation properties, effectively preventing the positive electrode tab 21 of the positive electrode 2 from being inserted backwards into the negative electrode 3, thus preventing a short circuit. The blocking element 4 has high-temperature resistance, maintaining its mechanical properties and dimensional stability even at high temperatures. During cell operation, even if a large amount of heat is generated causing the cell temperature to rise steadily, the performance of the blocking element 4 remains unaffected, thus effectively preventing the positive electrode tab 21 of the positive electrode 2 from being inserted backwards into the negative electrode 3. Furthermore, the blocking element 4 has good chemical inertness, effectively preventing corrosion from the electrolyte.

[0043] In some embodiments, the adhesive is made of one or a mixture of natural rubber, synthetic rubber, silicone, and polyurethane. The synthetic rubber can be general-purpose rubbers such as styrene-butadiene rubber, neoprene rubber, and butyl rubber, or specialty rubbers such as silicone rubber and fluororubber. An adhesive made from one or more of the above materials is applied to the separator body 1 to form an organic adhesive coating. This organic adhesive coating ensures effective adhesion to the separator body 1 and the aforementioned blocking member 4, thereby ensuring a stable connection between the blocking member 4 and the separator body 1 after subsequent adhesion. The organic adhesive formed from one or more of the above materials maintains stable performance even at extreme temperatures, and can withstand high temperatures while maintaining adhesion. During the operation of the lithium-ion battery, heat is generated, but this heat does not affect the adhesive's performance, thus preventing the blocking member 4 from detaching from the separator body 1. Furthermore, the adhesive has excellent chemical corrosion resistance, ensuring effective adhesion to the blocking member 4 even when immersed in electrolyte.

[0044] like Figure 3 As shown, in some embodiments, the height H1 of the adhesive ranges from 0.1mm to 10mm. Specifically, the height of the adhesive along the diaphragm body 1 can be 1mm, 2mm, 3mm, etc., without much limitation; designers can design according to actual needs. If the height H1 of the adhesive is less than 0.1mm, the blocking element 4 cannot be effectively bonded. If the height H1 of the adhesive is greater than 10mm, it will result in adhesive waste and may bond with the negative electrode plate 3. By limiting the height of the adhesive coating on the diaphragm body 1, the area for subsequent effective bonding of the blocking element 4 can be guaranteed, thereby ensuring that the blocking element 4 is stably set on the diaphragm body 1. Moreover, by reasonably designing the height of the adhesive, the amount of adhesive used can be saved, improving economy.

[0045] In some embodiments, the thickness L1 of the blocking member 4 ranges from 1µm to 1000µm. Specifically, the thickness L1 of the blocking member 4 can be 10µm, 20µm, 30µm, 40µm, etc. The designer can determine the thickness L1 of the blocking member 4 according to the actual cell conditions, without imposing too many restrictions here. Since the thickness L1 of the blocking member 4 determines the range of the edge of the negative electrode plate 3 covered, when the thickness L1 of the blocking member 4 is less than 1µm, it cannot prevent the positive electrode tab 21 from contacting the first end of the negative electrode plate 3; when the thickness L1 of the blocking member 4 is greater than 1000µm, it will affect the installation of the positive electrode plate 2, making it impossible for the separator body 1 to effectively adhere to the positive electrode plate 2. By reasonably designing the thickness of the blocking member 4, the end of the negative electrode plate 3 can be effectively blocked, thereby reducing the risk of the positive electrode tab 21 being inserted backwards into the negative electrode plate 3 and reducing the risk of thermal runaway.

[0046] In some embodiments, the blocking member 4 completely covers the end of the negative electrode plate 3. With this configuration, the blocking member 4 can completely prevent the positive electrode tab 21 from being inserted into the negative electrode plate 3, thereby completely eliminating the risk of internal short circuits in the cell caused by the positive electrode tab 21 being inserted backwards into the negative electrode plate 3. Furthermore, the blocking member 4 can effectively suppress lithium plating, thereby completely solving the problem of lithium plating across the separator body 1 at the end of the negative electrode plate 3 facing the blocking member 4, causing internal short circuits in the cell.

[0047] In some embodiments, in order to prevent the lithium plating phenomenon from causing a short circuit inside the cell at the periphery of the negative electrode 3, a blocking member 4 is fixedly provided at the edge of the separator body 1 along the circumferential direction of the separator body 1. The blocking member 4 forms a closed U-shape, which can effectively suppress the lithium plating phenomenon at the edge of the negative electrode 3, thereby eliminating the short circuit problem caused by the lithium plating crossing the separator body 1 and short-circuiting with the positive electrode 2 at the edge of the negative electrode 3.

[0048] In some embodiments, the diaphragm body 1 and the blocking member 4 are integrally formed. The diaphragm body 1 and the blocking member 4 are designed as an integrated structure, integrally formed during manufacturing, eliminating the need for applying adhesive and then bonding the blocking member 4, thus simplifying the manufacturing process. Furthermore, since there is no need to use adhesive to fix the blocking member 4, adhesive costs are saved, reducing the risk of the positive electrode tab 21 being inserted backwards into the negative electrode sheet 3 while ensuring the economic efficiency of manufacturing the diaphragm structure. It also ensures the stability of the connection between the diaphragm body 1 and the blocking member 4. In this embodiment, the diaphragm can be made of polyolefin materials, or a modified material can be coated on a polyolefin material. Specifically, the diaphragm uses polyethylene (PE) or polypropylene (PP) as the polyolefin material. The diaphragm body 1 made of polyethylene has low resistance, high ion permeability, and a melting point of approximately 130-140°C, ensuring the conductivity of the battery cell. The diaphragm body 1 made of polypropylene has better high-temperature resistance than polyethylene (melting point approximately 160-170°C), but slightly lower porosity, also ensuring the conductivity of the battery cell. Furthermore, multi-layer composite structures (such as PP / PE / PP) can be used to manufacture the separator to balance heat resistance and mechanical strength. Alternatively, a ceramic coating (such as Al2O3 or SiO2) can be applied to the separator body 1; coating with ceramic particles improves the high-temperature resistance, mechanical strength, and electrolyte wettability of the separator body 1, while reducing thermal shrinkage. Alternatively, a polymer coating (such as PVDF or aramid) can be applied to the separator body 1 to enhance its thermal stability and chemical inertness, while also improving electrolyte absorption capacity. Moreover, the thickness of the separator body 1 is typically between 5μm and 40μm. Consumer lithium-ion batteries often use ultra-thin separators of 16μm-25μm, while power lithium-ion batteries require thicker films of 20μm-40μm to ensure mechanical strength. The porosity of the separator body 1 needs to reach 35%-60%, with a pore size range of 0.03μm-0.5μm. Uniform pore size distribution can reduce the internal resistance of the cell and avoid excessive local current. Furthermore, the diaphragm body 1 needs to be resistant to corrosion from highly polar organic electrolytes (such as LiPF6) and should not decompose or swell during long-term use.

[0049] This embodiment also provides a battery cell, including a positive electrode 2, a negative electrode 3, and a separator structure as described above, with the separator structure sandwiched between the positive electrode 2 and the negative electrode 3. Using the separator structure described above in the battery cell can reduce the risk of the positive electrode tab 21 being inserted backwards into the negative electrode 3, and can suppress lithium plating, thereby reducing the risk of internal short circuits in the battery cell.

[0050] This embodiment also provides a battery module, including multiple sets of cells as described above, which are connected in series or in parallel. The battery module uses a metal frame or plastic casing to fix the multiple sets of cells, preventing displacement or damage to the cells due to vibration or impact. Using the cells as described above can reduce the risk of the positive electrode tab 21 being inserted backwards into the negative electrode plate 3, and can suppress lithium plating, thereby reducing the risk of internal short circuits within the cells.

[0051] This embodiment also provides a vehicle including the battery module described above, which can reduce the risk of the positive electrode tab 21 being inserted backward into the negative electrode plate 3 and can suppress lithium plating, thereby reducing the risk of internal short circuit in the battery cell.

[0052] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A diaphragm structure, characterized in that, include: A diaphragm body (1) is sandwiched between a positive electrode plate (2) and a negative electrode plate (3); The blocking member (4) is made of insulating material. The blocking member (4) is fixedly disposed on the side of the diaphragm body (1) facing the negative electrode plate (3), and the blocking member (4) is located at the first end of the negative electrode plate (3). The first end is located on the same side as the end of the positive electrode plate (2) with the positive electrode tab (21). The blocking member (4) can prevent the positive electrode tab (21) from contacting the first end of the negative electrode plate (3).

2. The diaphragm structure according to claim 1, characterized in that, The diaphragm body (1) is coated with adhesive on the side facing the negative electrode plate (3), and the blocking member (4) is bonded to the diaphragm body (1) by adhesive.

3. The diaphragm structure according to any one of claims 1-2, characterized in that, The material of the blocking element (4) is one or a mixture of polyimide, Teflon, glass fiber, and silicone.

4. The diaphragm structure according to claim 2, characterized in that, The adhesive is made of one or a mixture of natural rubber, synthetic rubber, silicone, and polyurethane.

5. The diaphragm structure according to claim 2, characterized in that, The height of the adhesive ranges from 0.1mm to 10mm.

6. The diaphragm structure according to any one of claims 1-2, characterized in that, The thickness of the blocking element (4) ranges from 1um to 1000um.

7. The diaphragm structure according to any one of claims 1-2, characterized in that, The blocking element (4) completely covers the end of the negative electrode plate (3).

8. A battery cell, characterized in that, It includes a positive electrode (2), a negative electrode (3), and a diaphragm structure as described in any one of claims 1-7, wherein the diaphragm structure is sandwiched between the positive electrode (2) and the negative electrode (3).

9. A battery module, characterized in that, It includes multiple sets of battery cells as described in claim 8, wherein the multiple sets of battery cells are connected in series or in parallel.

10. A vehicle, characterized in that, Includes the battery module as described in claim 9.

Images