Battery cell top cover, battery cell, battery module, battery pack and vehicle

Abstract

The battery cell top cover comprises a top cover main body, a top cover body and a cover body, the anti-explosion valve is arranged on the same side as the positive electrode contact and the negative electrode contact of the battery cell, and a protective layer is arranged on one side, facing the interior of the battery cell, of the anti-explosion valve. The invention further relates to a battery cell comprising the battery cell top cover, a battery module, a battery pack, a vehicle and a method for manufacturing the battery cell top cover.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of power batteries, in particular to a battery cell top cover with an anti-corrosion designed explosion-proof valve, a battery cell, a battery module, a battery pack and a vehicle. BACKGROUND

[0002] With the rapid development of new energy vehicles, lithium ion power batteries as the power source also step into the fast lane, and the safety of the battery is particularly important.

[0003] Currently, an explosion-proof valve is usually arranged on the top cover of a single battery to release pressure in the case of thermal runaway. However, in order to avoid the explosion-proof valve arranged towards the vehicle cabin from exploding and spewing high-temperature and high-pressure gas into the cabin, many batteries are currently arranged in an inverted structure of the battery cell. However, in the case of the inverted battery cell, the electrolyte is in contact with the explosion-proof valve, and the explosion-proof valve is usually thin and has a notch thereon, which is easy to be corroded through, which will cause electrolyte leakage and thus safety problems.

[0004] In addition, if the explosion-proof valve is corroded through by the electrolyte to cause leakage, the entire battery pack, rather than a single battery cell, usually needs to be replaced, and the cost of replacing the battery pack is very high.

[0005] Therefore, in order to avoid the risk of corrosion of the explosion-proof valve caused by the inverted battery cell without significantly increasing the cost, it is desirable to provide a battery cell top cover with an anti-corrosion designed explosion-proof valve, so as to further improve the safety of the battery and reduce the cost and be easy to implement. SUMMARY

[0006] The summary is provided to introduce some concepts in a simplified form that will be further described in the following detailed description. The summary is not intended to identify key or essential features of the claimed subject matter nor is it intended to be used to determine the scope of the claimed subject matter.

[0007] In view of the above problems, according to a first aspect of the present application, a battery cell top cover for a battery cell is provided, comprising: a top cover body; an explosion-proof valve arranged on the same side as positive and negative contacts of the battery cell, wherein a protective layer is arranged on a side of the explosion-proof valve facing the inside of the battery cell.

[0008] In the technical scheme of the embodiment of the present application, a protective layer (for example, a passivation layer) is arranged on the surface of the explosion-proof valve of the battery cell to avoid contact between the electrolyte and the explosion-proof valve, which can avoid the problems of corrosion and leakage caused by contact between the electrolyte and the explosion-proof valve in the case of the inverted battery cell, further improve the safety of the battery, and reduce the cost and be easy to implement.

[0009] According to an embodiment of the present application, the protective layer comprises an anodic oxidation layer, a polymer film, a UV cured film or a powder coating.

[0010] According to a further embodiment of the present invention, the explosion-proof valve further includes an explosion-proof sheet, the explosion-proof sheet sealing the explosion-proof hole reserved on the top cover of the battery cell, the explosion-proof sheet including a temperature-sensitive material layer, a metal layer and a nylon protective layer, wherein the protective layer is disposed on the side of the explosion-proof sheet facing the inside of the battery cell.

[0011] According to a further embodiment of the present invention, the temperature-sensitive material layer is made of one of polypropylene (PP), polyethylene terephthalate (PET), high-density polyethylene (HDPE), polyvinyl chloride (PVC), low-density polyethylene (LDPE), polystyrene (PS), and polycarbonate (PC).

[0012] According to a further embodiment of the invention, the metal layer is made of one of aluminum, copper, or stainless steel.

[0013] According to a further embodiment of the present invention, the explosion-proof valve is provided with multiple reinforcing ribs and grooves.

[0014] According to a second aspect of the present invention, a method for manufacturing a battery cell top cover is provided, the method comprising: forming a top cover body; forming an explosion-proof valve on the same side of the positive and negative contacts of the battery cell; and forming a protective layer on the explosion-proof valve on the side facing the interior of the battery cell.

[0015] According to one embodiment of the present invention, the protective layer includes an anodized layer, a polymer film, a UV-cured film, or a powder coating.

[0016] According to a further embodiment of the present invention, the temperature-sensitive material layer is made of one of polypropylene (PP), polyethylene terephthalate (PET), high-density polyethylene (HDPE), polyvinyl chloride (PVC), low-density polyethylene (LDPE), polystyrene (PS), and polycarbonate (PC), and the metal layer is made of one of aluminum, copper, or stainless steel.

[0017] According to a further embodiment of the present invention, the explosion-proof valve is provided with multiple reinforcing ribs and grooves.

[0018] According to a third aspect of the present invention, a battery cell is provided, the battery cell comprising: a battery cell top cover as described in any of the preceding aspects; a bare battery cell; a battery cell insulating film surrounding the bare battery cell; and a housing disposed outside the battery cell insulating film, the housing being connected to the battery cell top cover by laser welding.

[0019] According to a third aspect of the present invention, a battery module comprising a plurality of cells as described in the foregoing aspects is provided.

[0020] According to a fourth aspect of the present invention, a battery pack comprising a plurality of battery modules as described in the foregoing aspects is provided.

[0021] According to a fifth aspect of the invention, a vehicle is provided comprising a battery pack as described in the foregoing aspects.

[0022] To address the problems existing in the prior art, this invention provides a corrosion-resistant design scheme for explosion-proof valves. By setting a passivation protective layer on the surface of the explosion-proof valve, the electrolyte is prevented from contacting the explosion-proof valve, thereby avoiding safety and economic problems caused by corrosion of the explosion-proof valve.

[0023] These and other features and advantages will become apparent from the following detailed description and with reference to the accompanying drawings. It should be understood that the foregoing general description and the following detailed description are illustrative only and do not limit the scope of the claims. Attached Figure Description

[0024] To gain a more detailed understanding of the manner in which the features of this disclosure are described above, reference can be made to the various embodiments for a more specific description of the above-briefly summarized aspects, some of which are illustrated in the accompanying drawings. However, it should be noted that the drawings illustrate only certain typical aspects of this disclosure and should not be considered as limiting its scope, as this description may allow for other equivalent and effective aspects.

[0025] Figure 1 A schematic diagram of the structure of a square battery cell in the prior art is shown.

[0026] Figure 2 A top view of the cell top cover of an explosion-proof valve with a corrosion-resistant design according to an embodiment of the present disclosure is shown.

[0027] Figure 3 A side view of the cell top cover of an explosion-proof valve with a corrosion-resistant design according to an embodiment of the present disclosure is shown.

[0028] Figure 4 An example flowchart of a method for manufacturing a cell top cover of an explosion-proof valve with a corrosion-resistant design according to an embodiment of the present disclosure is shown.

[0029] Figure 5 An example vehicle including the battery pack disclosed herein is shown. Detailed Implementation

[0030] The following detailed description is sufficient to enable any person skilled in the art to understand the technical content of one or more embodiments of this specification and to implement them accordingly. Furthermore, based on the specification, claims, and drawings disclosed herein, those skilled in the art can easily understand the objects and advantages associated with one or more embodiments of this specification. Throughout this specification, the term "vehicle" refers to any type of automobile, including but not limited to cars, vans, trucks, buses, etc. For simplicity, the invention is described in relation to "automobile." The terms "A or B" as used in this specification mean "A and B" and "A or B," and do not imply that A and B are exclusive unless otherwise stated.

[0031] As mentioned above, explosion-proof valves are usually installed on the top cover of the battery cells to release pressure and prevent explosion in the event of thermal runaway. However, in order to avoid the explosion-proof valve facing the vehicle compartment bursting and spraying high-temperature and high-pressure gas into the compartment, many batteries are now designed with the cells inverted. In this case, the contact between the electrolyte and the explosion-proof valve (usually a thin metal sheet) may cause corrosion problems and lead to electrolyte leakage.

[0032] To address this issue, this specification proposes an explosion-proof valve design that avoids direct contact between the electrolyte and the valve by setting an anti-corrosion protective layer on the valve surface. This avoids the aforementioned electrolyte leakage problem and is cost-effective and easy to implement.

[0033] As the core component of a power battery, the battery cell is the basic unit for storing energy in a battery system, determining core performance characteristics such as energy density, power performance, safety, and lifespan. Structurally, battery cells are mainly divided into three types: cylindrical, prismatic, and pouch cells. The following explanation uses a prismatic cell as an example; however, it should be understood that the explosion-proof valve design of this invention is not limited to prismatic cells.

[0034] For example, see Figure 1 It shows a schematic diagram of the structure of a prior art square battery cell 100. For example... Figure 1 As shown, the square battery cell 100 may include a battery cell top cover 102, a bare battery cell 104, a battery cell insulating film 106, and a housing 108.

[0035] The top cover 102 of the battery cell is provided with a positive terminal 110, a negative terminal 112, and an explosion-proof valve 114 located on the same side as the positive terminal 110 and the negative terminal 112.

[0036] The bare cell 104 (also known as the electrode assembly) can be formed by a winding process or a stacking process of a positive electrode sheet, a negative electrode sheet and a separator film, and the cell insulating film 106 surrounds the bare cell 104.

[0037] The housing 108 includes a base plate and side plates connected to the base plate. The base plate and side plates enclose a receiving cavity, wherein the housing 108 has an opening communicating with the receiving cavity. The cell top cover 102 can be placed over the opening to close the receiving cavity. For example, the cell top cover 102 and the housing 108 can be connected by laser welding. The bare cell 104 is placed in the receiving cavity, and the electrolyte can be immersed in the bare cell 104, thereby playing a role in conducting ions between the positive electrode and the negative electrode.

[0038] Therefore, when the battery cell is inverted, the electrolyte will come into contact with the explosion-proof valve, posing a risk of corrosion and breakdown of the valve. To avoid this situation, please refer to the following... Figures 2-3 An example structure of the corrosion-resistant explosion-proof valve of the present invention is described in detail.

[0039] Figures 2-3 Top and side views of the cell top cover 200 of an explosion-proof valve with a corrosion-resistant design according to an embodiment of the present disclosure are shown respectively.

[0040] like Figures 2-3 As shown, the cell top cover 200 may include a top cover body 202. The top cover body 202 may include, for example, a top cover plate, a positive terminal, a negative terminal, or an electrolyte injection port. In a single cell, the positive and negative terminals, adapter plates, and cell tabs of the top cover are welded together to ensure the conduction of the cell's charging and discharging current. In a battery module, the top cover terminals are laser-welded and bolted to the busbar to form a series / parallel connection. The electrolyte injection port is mainly used to inject electrolyte into the cell after the top cover is welded to the casing, and then the injection port is sealed with a sealing pin using laser welding. During the sealing inspection after the top cover is welded, helium gas is generally introduced through the injection port to detect the pressure change inside the battery, thereby judging the weld sealing performance.

[0041] In addition, the top cover 200 of the battery cell may also include an explosion-proof valve 204 disposed on the same side as the positive and negative contacts of the battery cell, wherein an anti-corrosion protective layer 206 is disposed on the side of the explosion-proof valve 204 facing the inside of the battery cell.

[0042] In one embodiment, the protective layer 206 may include, but is not limited to, an anodized layer, a polymer film, a UV-cured film, or a powder coating.

[0043] In one embodiment, the explosion-proof valve 204 may further include an explosion-proof sheet that can seal the explosion-proof hole reserved on the top cover of the battery cell. The explosion-proof sheet may include a temperature-sensitive material layer, a metal layer, and a nylon protective layer. The protective layer 206 may be disposed on the side of the explosion-proof sheet facing the inside of the battery cell.

[0044] In a further embodiment, the aforementioned temperature-sensitive material layer may be made of one of polypropylene (PP), polyethylene terephthalate (PET), high-density polyethylene (HDPE), polyvinyl chloride (PVC), low-density polyethylene (LDPE), polystyrene (PS), or polycarbonate (PC).

[0045] In a further embodiment, the metal layer may be made of aluminum, copper or stainless steel.

[0046] In one embodiment, the explosion-proof valve 204 may also be provided with multiple reinforcing ribs and grooves. When the internal pressure of the battery increases and exceeds the opening pressure of the explosion-proof valve, the explosion-proof valve will rupture at the grooves and open to release pressure.

[0047] Of course, it is understood that explosion-proof valves can be designed in any other manner known in the art.

[0048] Figure 4 An example flowchart of a method 400 for manufacturing a cell top cover with a corrosion-resistant design for an explosion-proof valve according to an embodiment of the present disclosure is shown.

[0049] Method 400 begins at step 402, forming a top cover body 202. The top cover body 202 may include, for example, a top cover plate, a positive electrode post, a negative electrode post, or an injection port.

[0050] In step 404, an explosion-proof valve 204 is formed on the same side of the positive and negative contacts of the battery cell.

[0051] In step 406, a protective layer 206 is formed on the side of the explosion-proof valve facing the inside of the battery cell.

[0052] In one embodiment, the protective layer 206 may be formed using techniques such as anodizing or UV curing for corrosion resistance.

[0053] For example, the protective layer 206 can be an anodized layer, a polymer film, a UV-cured film, or a powder coating. Of course, it is understood that the protective layer 206 can also be formed using any other anti-corrosion technology or material known in the art.

[0054] In one embodiment, forming the explosion-proof valve 204 further includes forming an explosion-proof sheet that seals a pre-drilled explosion-proof hole on the top cover of the battery cell. The explosion-proof sheet may include a temperature-sensitive material layer, a metal layer, and a nylon protective layer. In this case, the protective layer may be formed on the side of the explosion-proof sheet facing the interior of the battery cell.

[0055] In one embodiment, the temperature-sensitive material layer may be made of one of polypropylene (PP), polyethylene terephthalate (PET), high-density polyethylene (HDPE), polyvinyl chloride (PVC), low-density polyethylene (LDPE), polystyrene (PS), and polycarbonate (PC), and the metal layer may be made of one of aluminum, copper, or stainless steel.

[0056] In one embodiment, the explosion-proof valve is provided with multiple reinforcing ribs and grooves (e.g., annular, U-shaped, arched, etc.).

[0057] In one embodiment of the present invention, a number of individual battery cells (i.e., battery cells) can be assembled together to form a battery module. The battery module contains two or more battery cells, the specific number of which depends on the application of the battery module and the parameters of the individual battery module.

[0058] For example, in a battery module, multiple battery cells can be arranged sequentially along the length of the module. Of course, they can also be arranged in any other manner. Furthermore, these multiple battery cells can be secured using fasteners.

[0059] In one embodiment of this application, two or more of the above-described battery modules can be assembled into a battery pack. The number of battery modules contained in the battery pack depends on the application of the battery pack and the parameters of individual battery modules. The battery pack may include a battery box and multiple battery modules disposed within the battery box. The battery box includes an upper box and a lower box, the upper box being able to cover and fit snugly onto the lower box to form a closed space for accommodating the battery modules. Two or more battery modules can be arranged in the battery box in a desired manner.

[0060] Figure 5 An example vehicle 500 including a battery pack according to this application is shown. The vehicle may include, but is not limited to, pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, etc. Currently, most passenger vehicle power batteries are single-pack systems (i.e., battery packs), which use assembly technology to integrate individual battery cells into a battery pack, mainly involving structure, thermal management, electrical connection design, and BMS technology. Assembly technology may include, for example, MTP, CTP, CTC, CTB, or MTP. For example, MTP technology refers to first integrating cells into modules, and then integrating modules into a pack. The core of MTP assembly technology lies in module design; a module generally consists of a frame (end plate, side plate, base plate), cells, high and low voltage electrical connection components, CCS components, insulation and buffer components. CTP technology refers to the technology of directly integrating cells into the pack. The characteristic of CTP technology is that the cells and the pack are permanently bonded and fixed by high-strength structural adhesive, therefore they cannot be disassembled and maintained.

[0061] In the case of the battery cell being inverted, since the pressure relief valve of the battery cell faces downwards, combined with the unique pressure relief path design of the battery pack, it can ensure that the battery cell can quickly release heat and pressure downwards in the event of thermal runaway, thereby ensuring the safety of the passenger compartment above. In addition, through the pressure relief valve design of this invention, a protective film is set on the pressure relief valve facing the inside of the battery cell, which can prevent electrolyte from corroding the pressure relief valve and causing leakage problems. Moreover, it is low in cost and easy to implement.

[0062] The foregoing description includes examples of various aspects of the claimed subject matter. It is certainly impossible to describe every conceivable combination of components or methods for the purpose of depicting the claimed subject matter, but those skilled in the art will recognize that many further combinations and arrangements of the claimed subject matter are possible. Thus, the disclosed subject matter is intended to cover all such changes, modifications, and variations that fall within the spirit and scope of the appended claims.

Claims

1. A battery cell top cover, comprising: Top cover body; An explosion-proof valve is located on the same side as the positive and negative contacts of the battery cell. A protective layer is provided on the side of the explosion-proof valve facing the inside of the battery cell.

2. The cell top cover as described in claim 1, characterized in that, The protective layer includes an anodized layer, a polymer film, a UV-cured film, or a powder coating.

3. The cell top cover as described in claim 1, characterized in that, The explosion-proof valve further includes an explosion-proof disc, which seals a pre-drilled explosion-proof hole on the top cover of the battery cell. The explosion-proof disc includes a temperature-sensitive material layer, a metal layer, and a nylon protective layer. The protective layer is disposed on the side of the explosion-proof sheet facing the inside of the battery cell.

4. The cell top cover as described in claim 3, characterized in that, The temperature-sensitive material layer is made of one of the following: polypropylene (PP), polyethylene terephthalate (PET), high-density polyethylene (HDPE), polyvinyl chloride (PVC), low-density polyethylene (LDPE), polystyrene (PS), and polycarbonate (PC).

5. The cell top cover as described in claim 3, characterized in that, The metal layer is made of one of aluminum, copper, or stainless steel.

6. The cell top cover as described in claim 1, characterized in that, The explosion-proof valve is provided with multiple reinforcing ribs and grooves.

7. A method for manufacturing a cell top cover for a battery cell, comprising: Forming the main body of the top cover; An explosion-proof valve is formed on the same side of the positive and negative contacts of the battery cell; as well as A protective layer is formed on the side of the explosion-proof valve facing the inside of the battery cell.

8. The method as described in claim 7, characterized in that, The protective layer includes an anodized layer, a polymer film, a UV-cured film, or a powder coating.

9. The method as described in claim 7, characterized in that, The explosion-proof valve further includes an explosion-proof disc, which seals a pre-drilled explosion-proof hole on the top cover of the battery cell. The explosion-proof disc includes a temperature-sensitive material layer, a metal layer, and a nylon protective layer. The protective layer is disposed on the side of the explosion-proof sheet facing the inside of the battery cell.

10. The method as described in claim 9, characterized in that, The temperature-sensitive material layer is made of one of polypropylene (PP), polyethylene terephthalate (PET), high-density polyethylene (HDPE), polyvinyl chloride (PVC), low-density polyethylene (LDPE), polystyrene (PS), and polycarbonate (PC), and the metal layer is made of one of aluminum, copper, or stainless steel.

11. The method as described in claim 7, characterized in that, The explosion-proof valve is provided with multiple reinforcing ribs and grooves.

12. A battery cell, comprising: The battery cell top cover as described in any one of claims 1-6; Bare battery cells; The cell insulation film surrounding the bare cell; as well as The housing is disposed outside the insulating film of the battery cell, and the housing is connected to the top cover of the battery cell by laser welding.

13. A battery module comprising a plurality of cells as described in claim 12.

14. A battery pack comprising a plurality of battery modules as described in claim 13.

15. A vehicle comprising the battery pack as claimed in claim 14.

Images