Battery cell cover plate assembly, battery cell, and battery pack

Abstract

The application relates to the technical field of batteries and discloses a battery cell cover plate assembly, a battery cell and a battery pack. The battery cell cover plate assembly comprises a cover plate and a stepped liquid injection port. The stepped liquid injection port comprises at least two steps, the first step is arranged through the cover plate, the remaining steps are arranged on the outer surface of the cover plate, the opening size of the first step is smaller than the minimum opening size of the remaining steps; the first step is sealed by a first sealing nail; the outermost step away from the cover plate is sealed by a second sealing nail after each liquid injection, and is removed together with the second sealing nail before the next liquid injection to expose the next step for secondary or multiple liquid injection. The battery cell cover plate assembly provided by the application comprises a stepped liquid injection port with at least two steps, when the electrolyte of the battery cell is insufficient, the outermost step and the second sealing nail can be removed, so that secondary or multiple liquid injection can be carried out on the battery cell through the first step, the cycle life of the battery cell is prolonged, and the reliability of the step utilization of the retired battery cell is ensured.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of battery, in particular to a battery cell cover plate assembly, a battery cell and a battery pack. BACKGROUND

[0002] With the continuous development of lithium ion battery technology, higher requirements are put forward for the cycle life of lithium ion battery.

[0003] Lithium ion batteries are pre-reserved with liquid injection ports to fill electrolyte, which is used to maintain the cycle life of lithium ions. Generally, lithium ion batteries are provided with internal liquid injection ports. After the electrolyte is injected into the battery cell shell, the liquid injection port is sealed by welding a sealing pin. During the cycle process of the battery cell, the electrolyte will continuously repair the solid electrolyte interface film on the surface of the positive and negative electrode materials, which will be continuously consumed. However, the current battery cell cannot be refilled with electrolyte. Until the electrolyte injected for the first time is consumed in the continuous charging and discharging cycle of the battery cell, the cycle life of the battery cell ends.

[0004] The battery cell in the related art has a situation of insufficient electrolyte during the cycle process, which leads to a shortened service life of the lithium ion battery cell. SUMMARY

[0005] Therefore, the present application provides a battery cell cover plate assembly, a battery cell and a battery pack to solve the problem of insufficient electrolyte during the cycle process of the battery cell and shortened service life.

[0006] In a first aspect, the present application provides a battery cell cover plate assembly, comprising a cover plate and a stepped liquid injection port. The stepped liquid injection port comprises at least two steps, the first step is provided through the cover plate, and the remaining steps are provided on the outer surface of the cover plate. The opening size of the first step is smaller than the smallest opening size of the remaining steps. The first step is sealed by a first sealing pin. The outermost step away from the cover plate is sealed by a second sealing pin after each injection, and is removed together with the second sealing pin before the next injection to expose the next step for secondary or multiple injections.

[0007] Beneficial effects: The purpose of the present application is to solve the problem of rapid attenuation of the cycle life of the battery cell due to insufficient electrolyte in the later stage of the cycle process. The stepped liquid injection port of the battery cell cover plate assembly provided by the present application is different from the traditional liquid injection port and is provided as a liquid injection port comprising at least two steps. When the first injected electrolyte of the battery cell is insufficient, the outermost step and the second sealing pin can be removed, so that the battery cell can be refilled through the first step. The setting of multiple steps allows multiple injections, thereby achieving the purpose of prolonging the cycle life of the battery cell. Since the stepped liquid injection port is provided with at least two steps, after the power battery is retired, the reliability of the step utilization of the retired battery cell can be ensured by refilling the electrolyte twice or multiple times.

[0008] In an alternative embodiment, the opening size of the stepped liquid injection port increases from the first step to the outermost step.

[0009] In an alternative embodiment, a terminal is further included, and the terminal is arranged on the cover plate; the height of the outermost step of the stepped liquid injection port protruding from the outer surface of the cover plate is not greater than the height of the terminal protruding from the outer surface of the cover plate.

[0010] In an alternative embodiment, the total height of the stepped liquid injection port protruding from the outer surface of the cover plate is H, and H≤3.2mm.

[0011] In an alternative embodiment, the material wall thickness of each step of the stepped liquid injection port is T, and 0.5mm≤T≤2.5mm.

[0012] In an alternative embodiment, the outermost step of the stepped liquid injection port is a circular ring, and the maximum inner diameter of the outermost step is D, and D≤30mm.

[0013] In an alternative embodiment, each step of the stepped liquid injection port includes a first sealing surface extending in the thickness direction of the cover plate and a second sealing surface parallel to the cover plate, and there are at least one step, and the included angle between the second sealing surface and the first sealing surface is α, and α>90°.

[0014] In an alternative embodiment, the top surface of the second sealing nail does not exceed the end surface of the outermost step.

[0015] In a second aspect, the application further provides an electric core, including a shell, a pole group, and the electric core cover plate assembly in the above technical solution, the shell has a receiving cavity, and the shell has an open end; the pole group is arranged in the receiving cavity of the shell; the electric core cover plate assembly is arranged at the open end of the shell, and the pole group is packaged in the shell, and the stepped liquid injection port of the electric core cover plate assembly is in communication with the receiving cavity.

[0016] Beneficial effects: because the electric core includes the electric core cover plate assembly, it has the same effect as the electric core cover plate assembly, which is not described here.

[0017] In a third aspect, the application further provides a battery pack including the electric core in the above technical solution.

[0018] Beneficial effects: because the battery pack includes the electric core, it has the same effect as the electric core, which is not described here. BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to make the technical solutions in the embodiment of the present application or the prior art clearer, the accompanying drawings needed in the description of the embodiment or the prior art will be briefly introduced. Obviously, the accompanying drawings in the following description are only some embodiments of the present application, and other accompanying drawings can be obtained by those skilled in the art without any creative effort based on these accompanying drawings.

[0020] Figure 1 A top view of an electric cell cover plate assembly according to an embodiment of the present application;

[0021] Figure 2 A sectional view along A-A of the structure shown in Figure 1

[0022] A sectional view along A-A of the structure shown in Figure 3 Figure 2 A sectional view along A-A of the structure shown in

[0023] Figure 4 Figure 3 A sectional view along A-A of the structure shown in

[0024] Figure 5 A sectional view along A-A of the structure shown in

[0025] Figure 6 A sectional view along A-A of the structure shown in Figure 5

[0026] A sectional view along A-A of the structure shown in Figure 7

[0027] A sectional view along A-A of the structure shown in Figure 8 Figure 7 A sectional view along A-A of the structure shown in

[0028] Figure 9 A sectional view along A-A of the structure shown in Figure 8

[0029] A sectional view along A-A of the structure shown in Figure 10 Figure 9 A sectional view along A-A of the structure shown in

[0030]

[0031] 1, cover plate; 2, stepped injection port; 21, first stage; 22, outermost stage; 3, first sealing pin; 4, second sealing pin; 5, terminal. DETAILED DESCRIPTION

[0032] ​​​​​In order to make the purposes, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative efforts belong to the scope of the present application.

[0033] The embodiments of the present application are described below with reference to the drawings. Figures 1 to 10

[0034] According to the embodiments of the present application, in a first aspect, an electric cell cover plate assembly is provided, which comprises a cover plate 1 and a stepped liquid injection port 2. The stepped liquid injection port 2 comprises at least two steps, the first step 21 is provided through the cover plate 1, and the remaining steps are provided on the outer surface of the cover plate 1. The opening size of the first step 21 is smaller than the minimum opening size of the remaining steps. The first step 21 is sealed by a first sealing nail 3. The outermost step 22 away from the cover plate is sealed by a second sealing nail 4 after each liquid injection, and is removed together with the second sealing nail 4 before the next liquid injection to expose the next step for secondary or multiple liquid injection.

[0035] The purpose of the present application is to solve the problem that the cycle life of the electric cell is attenuated too quickly due to insufficient electrolyte at the later stage of the cycle of the electric cell. The electric cell cover plate assembly provided by the present application is different from the traditional liquid injection port. The stepped liquid injection port 2 is provided as a liquid injection port comprising at least two steps. When the first injection of electrolyte into the electric cell is insufficient, the outermost step 22 and the second sealing nail 4 can be removed, so that the first step 21 can be used for secondary injection of electrolyte into the electric cell. The multiple steps can be used for multiple liquid injection, thereby achieving the purpose of prolonging the cycle life of the electric cell. Since the stepped liquid injection port 2 is provided with at least two steps, after the power battery is retired, the reliability of the step utilization of the retired electric cell can be ensured by secondary or multiple electrolyte injection. Since the remaining steps are provided on the outer surface of the cover plate 1, the outermost step 22 and the second sealing nail 4 can be ground away during the subsequent secondary or multiple liquid injection, which is convenient for operation, facilitates accurate liquid injection, and facilitates welding of the second sealing nail on the next step after liquid injection, i.e. the outermost step after liquid injection, thereby reducing the welding difficulty, improving the welding quality, and ensuring the sealing effect.

[0036] Specifically, the outer surface of the cover plate 1 refers to the surface on the side opposite to the liquid injection direction of the cover plate. In the orientation shown in the drawings, the outer surface of the cover plate 1 is its upper surface. Figures 2 to 10

[0037] In some embodiments, the opening size of the stepped liquid injection port 2 increases from the first step 21 to the outermost step 22.

[0038] ​​Since the stepped liquid injection port 2 is arranged in a stepped manner, and the opening size of the stepped liquid injection port 2 increases from the first stepped portion 21 to the outermost stepped portion 22, the outermost stepped portion 22 and the second sealing nail 4 can be ground away during each injection, so that the next outer stepped portion is completely exposed, facilitating injection and assembly of the second sealing nail 4, reducing sealing difficulty, and improving the efficiency of secondary or multiple injections. At the same time, after the outermost layer and the second sealing nail 4 are ground away during multiple injections, the next outer stepped portion is used as a new outermost stepped portion 22, and a new second sealing nail 4 is used to seal it, which can effectively prevent electrolyte leakage during multiple injections.

[0039] Specifically, the contour shape of the stepped liquid injection port 2 is not limited, such as a circular shape or a square shape. When the contour of the stepped liquid injection port 2 is circular, the opening size refers to the inner diameter thereof.

[0040] In some embodiments, the terminal 5 is further included, and the terminal 5 is arranged on the cover plate 1; the height of the outermost stepped portion 22 of the stepped liquid injection port 2 protruding from the outer surface of the cover plate 1 is not greater than the height of the terminal 5 protruding from the outer surface of the cover plate 1.

[0041] In this way, the stepped liquid injection port 2 can realize secondary or multiple injections to prolong the service life of the battery cell while not affecting the welding and Pack or assembly of the single battery cell, and does not occupy additional space in the height direction of the battery cell.

[0042] In some embodiments, the total height of the stepped liquid injection port 2 protruding from the outer surface of the cover plate 1 is H, and H≤3.2mm.

[0043] Specifically, the total height of the stepped liquid injection port 2 protruding from the outer surface of the cover plate 1 is the total height of the outermost stepped portion 22 protruding from the outer surface of the cover plate 1, as shown in Figure 5 or Figure 7 H is not greater than 3.2mm, which can ensure that the welding and Pack or assembly of the single battery cell are not affected, and additional space in the height direction of the battery cell is not occupied.

[0044] Further, in some specific embodiments, H=3.0mm.

[0045] In some embodiments, the material wall thickness of each stepped portion of the stepped liquid injection port 2 is T, and 0.5mm≤T≤2.5mm.

[0046] Controlling the material wall thickness T of each stepped portion of the stepped liquid injection port 2 in the range of 0.5mm to 2.5mm can meet the total height requirement of the stepped liquid injection port 2, and also ensure the strength of the stepped liquid injection port, resist stress deformation during welding and sealing, and ensure the sealing effect.

[0047] Further, in some specific embodiments, T=1mm.

[0048] In some embodiments, the outermost step 22 of the stepped liquid inlet 2 is circular ring-shaped, and the maximum inner diameter of the outermost step 22 is D, D≤30mm.

[0049] The circular ring-shaped step design helps to accurately control the liquid injection amount and injection speed. The maximum inner diameter D of the outermost step 22 is less than 30mm, which can make the liquid injection more concentrated, reduce the risk of liquid splashing, and improve the accuracy of liquid injection. At the same time, it reduces the splashing and waste of electrolyte during the injection process, ensures that more electrolyte can enter the battery interior, thereby improving the utilization rate of materials.

[0050] Further, in some specific embodiments, D=26mm.

[0051] In some embodiments, the cover plate 1 and the stepped liquid inlet 2 are made of metal materials.

[0052] The cover plate 1 and the stepped liquid inlet 2 are both made of metal materials, which generally have high strength and hardness and can withstand large mechanical stress. This makes the cover plate 1 and the stepped liquid inlet 2 less likely to deform or be damaged during long-term use, thereby improving the overall durability and reliability of the battery cell and meeting the demand for repeated use of the battery cell.

[0053] Metal materials can be processed through stamping, welding, machining and other processes, and have good plasticity and processability. This makes it easy to manufacture complex-shaped stepped liquid inlets 2 and cover plates 1, and ensures high precision and consistency.

[0054] The surface of the metal material is smooth and flat, which is conducive to forming a tight sealing structure. By cooperating with the rubber sealing pin or metal sealing pin, a highly reliable sealing effect can be achieved, effectively preventing electrolyte leakage.

[0055] Further, the metal includes aluminum, steel, aluminum alloy, and steel alloy.

[0056] In some embodiments, the first step 21 of the stepped liquid inlet 2 is stamped and formed from the cover plate 1, and the remaining steps are welded to the cover plate 1.

[0057] The first step 21 is formed directly from the cover plate 1 by stamping and forming, making it an integral part of the cover plate 1, which reduces the joints between components and improves the stability and reliability of the overall structure. The remaining steps are connected to the cover plate 1 by welding, which allows flexible selection of welding positions and methods, facilitating adjustment and optimization of the assembly process. Welding provides high-strength connections, ensuring the firmness between the steps.

[0058] In some embodiments, the first sealing pin 3 is a rubber sealing pin, and the second sealing pin 4 is a metal sealing pin.

[0059] The first sealing nail 3 seals the first stage 21 of the stepped liquid injection port 2, adopts a rubber sealing nail, and plays a temporary sealing role. The rubber sealing nail can be removed for secondary or multiple liquid injection. Due to the good elasticity and plasticity of the rubber sealing nail, the rubber sealing nail can tightly fit the first stage 21 of the stepped liquid injection port 2 during installation, thereby forming a good initial sealing effect. This helps to prevent leakage of electrolyte during liquid injection. At the same time, before secondary liquid injection or multiple liquid injection, the outermost stage 22 and the second sealing nail 4 need to be polished off. At this time, the rubber sealing nail can prevent metal debris from entering the inside of the battery cell. Since the first sealing nail 3 will directly contact the electrolyte, the first sealing nail 3 is made of a material resistant to electrolyte corrosion.

[0060] The second sealing nail 4 seals the outermost stage 22, adopts a metal sealing nail, and can achieve a good sealing effect to effectively prevent electrolyte leakage.

[0061] The stepped liquid injection port 2 uses a combination of rubber sealing nails and metal sealing nails, providing a double sealing mechanism and increasing the sealing reliability of the entire battery cell.

[0062] In some embodiments, each stage of the stepped liquid injection port 2 includes a first sealing surface extending along the thickness direction of the cover plate 1 and a second sealing surface parallel to the cover plate 1. There is at least one stage, and the included angle between the second sealing surface and the first sealing surface is α, α > 90°.

[0063] In this way, the second sealing surface of the stage in the stepped liquid injection port 2 forms a bevel structure relative to the first sealing surface. This can increase the contact area between the sealing nail and the stage, increase the sealing surface, and enable the sealing nail to better fit the stage surface when being pressed in, thereby improving the sealing effect and reducing the risk of electrolyte leakage. At the same time, the bevel structure causes the sealing nail to be subjected to a certain self-locking force after being pressed in, i.e., the sealing nail has a tendency to tighten inward when subjected to force. This helps to prevent the sealing nail from loosening due to vibration or external impact, thereby improving the stability of the sealing. In addition, the bevel structure makes it easier to align and press the sealing nail into the stepped liquid injection port 2 during installation. This not only simplifies the installation process, but also reduces the problem of sealing failure caused by improper installation.

[0064] In some embodiments, the top surface of the second sealing nail 4 does not exceed the end surface of the outermost stage 22.

[0065] In this way, the sealing nail can avoid occupying additional space in the height direction of the battery cell, making the overall size of the battery cell more compact. In addition, since the top surface of the second sealing nail 4 does not exceed the end surface of the outermost stage 22, the sealing nail can be effectively prevented from being physically damaged. For example, during transportation, installation or use, the sealing nail will not be damaged due to collision or friction, thereby improving its service life and the reliability of the sealing.

[0066] Specifically, the procedure for secondary or multiple injections is as follows:

[0067] When the electrolyte injected initially is insufficient during continuous circulation, the outermost step 22 and the second sealing nail 4 are ground off. During grinding, the first sealing nail 3 can prevent metal debris from entering the cell. The outermost step 22 is ground using vacuum suction or airflow to remove metal debris.

[0068] After the outermost step 22 and the second sealing nail 4 are ground off, the first sealing nail 3 is removed. Electrolyte is injected in a temperature, humidity and dust controlled environment. After injection, the first step 21 is sealed with a new first sealing nail 3, and the next outermost step (which is now the outermost step 22) is sealed by welding with the second sealing nail 4.

[0069] Specifically, taking the stepped injection port 2 with a three-stage stepped design as an example, refer to... Figure 7 The three-stage ladder allows for three injections. The first injection is performed through the first stage 21. After injection, the first stage 21 is sealed with a rubber sealing pin. The outermost stage 22, the third stage, is then sealed with a metal sealing pin. Figure 8 As shown.

[0070] During the second injection, the third step and the metal sealing pin are ground off, leaving only two steps, such as... Figure 9 As shown. Remove the first sealing pin 3 and perform a second injection. After the injection is complete, seal the first-stage step 21 with a rubber sealing pin, and weld a metal sealing pin to the next outermost step (the second-stage step), which is the outermost step 22 in the current state, to achieve a seal, as shown. Figure 10 As shown.

[0071] During the third injection, the outermost step 22, which is the original second step, and the metal sealing pin are ground away, leaving only the first step 21. The first sealing pin 3 is then removed, and the third injection is performed. The first step 21 is a stepped hole, consisting of a narrow lower opening and a wide upper opening. After injection, a rubber sealing pin is used to seal the narrow lower opening of the first step 21, and a metal sealing pin is used to seal the wide upper opening, thus sealing the stepped injection port 2.

[0072] To verify the technical effectiveness of this invention, specific experimental examples are provided below. The test results are shown in Table 1.

[0073] Table 1:

[0074]

[0075] As can be seen from Table 1, for batteries with the same materials, the cycle life of the battery is significantly improved after secondary or multiple electrolyte injections.

[0076] According to the second aspect of the embodiments of the present application, there is further provided an electric core, comprising a shell, a pole group and the electric core cover plate assembly in the above embodiments, the shell has a containing cavity, the shell has an open end; the pole group is arranged in the containing cavity of the shell; the electric core cover plate assembly is arranged at the open end of the shell, encapsulating the pole group in the shell, and the stepped liquid injection port 2 of the electric core cover plate assembly is in communication with the containing cavity.

[0077] The electric core cover plate assembly provided by the present application can improve the situation that the electrolyte is not dried out during the cycle process when the electric core cover plate assembly is applied to the electric core. When the MOL stage of the electric core or the cycle life of the electric core reaches the set requirement, the outermost stepped stage 22 and the second sealing nail 4 are polished away, the first sealing nail 3 in the first stepped stage 21 is taken out, and the electrolyte is secondly injected. After the injection, the first stepped stage 21 is sealed by a new first sealing nail 3, and the outermost stepped stage 22 is sealed by a new second sealing nail 4, so as to better maintain or prolong the service life of the lithium ion electric core.

[0078] The electric core has the same effect as the electric core cover plate assembly, and thus will not be described here again.

[0079] According to the third aspect of the embodiments of the present application, there is further provided a battery pack, comprising the electric core in the above embodiments.

[0080] The battery pack has the same effect as the electric core, and thus will not be described here again.

[0081] Although the embodiments of the present application are described in conjunction with the drawings, various modifications and changes can be made by those skilled in the art without departing from the spirit and scope of the present application, and such modifications and changes fall within the scope defined by the appended claims.

Claims

1. An electrochemical cell cover plate assembly, comprising: The application relates to a cover plate of an electrochemical cell, comprising: a cover plate; a stepped liquid injection port, the stepped liquid injection port comprising at least two steps, a first step being provided through the cover plate, and the rest of the steps being provided on the outer surface of the cover plate, the opening size of the first step being smaller than the minimum opening size of the rest of the steps; the first step being sealed by a first sealing pin; the outermost step away from the cover plate being sealed by a second sealing pin after each liquid injection, and being removed together with the second sealing pin before the next liquid injection to expose the next step for secondary or multiple liquid injection; each step of the stepped liquid injection port comprising a first sealing surface extending along the thickness direction of the cover plate and a second sealing surface parallel to the cover plate, and there being at least one step, the included angle between the second sealing surface and the first sealing surface being alpha, alpha>90 DEG.

2. The cell cover plate assembly of claim 1, wherein, the opening size of the stepped liquid injection port increasing from the first step to the outermost step.

3. The cell cover plate assembly of claim 1 or 2, wherein, a terminal provided on the cover plate; the height of the outermost step of the stepped liquid injection port protruding from the outer surface of the cover plate being not greater than the height of the terminal protruding from the outer surface of the cover plate.

4. The cell cover plate assembly of claim 3, wherein, the total height of the stepped liquid injection port protruding from the outer surface of the cover plate being H, H<=3.2 mm.

5. The cell cover plate assembly of claim 1 or 2, wherein, the material wall thickness of each step of the stepped liquid injection port being T, 0.5 mm<=T<=2.5 mm.

6. The cell cover plate assembly of claim 1 or 2, wherein, the outermost step of the stepped liquid injection port being a circular ring, the maximum inner diameter of the outermost step being D, D<=30 mm.

7. The cell cover plate assembly of claim 1 or 2, wherein, the top surface of the second sealing pin not exceeding the end surface of the outermost step.

8. An electric cell characterized by The application relates to a shell of an electrochemical cell, comprising: a shell having a containing cavity, the shell having an open end; a pole group provided in the containing cavity of the shell; the electrochemical cell cover plate assembly of any one of claims 1 to 7 is provided at the open end of the shell, the pole group is encapsulated in the shell, and the stepped liquid injection port of the electrochemical cell cover plate assembly is in communication with the containing cavity.

9. A battery pack, characterized by, The application relates to an electrochemical cell comprising the electrochemical cell cover plate assembly.

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