Battery cell cover plate and battery cell

Abstract

A battery cell comprises a battery cell cover plate. The battery cell cover plate comprises: a top cover sheet (10), provided with a mounting hole (11) passing through a main body thereof; a pressure relief assembly (20), arranged in the mounting hole (11); and a separating member (30), arranged on the side of the top cover sheet (10) facing a battery cell casing (60) and covering the mounting hole (11) so as to separate the pressure relief assembly (20) from an electrolyte (100) in the battery cell casing (60). By providing the separating member (30), the pressure relief assembly (20) is separated from the electrolyte (100) in the battery cell casing (60). Even if the electrolyte (100) shakes back and forth in the battery cell casing (60), direct impact cannot be caused to the pressure relief assembly (20). Instead, force acts on the separating member (30), thus achieving the effect of well cushioning the impact force of the electrolyte (100), preventing the pressure relief assembly (20) from being opened in advance under the impact of the electrolyte (100), reducing the risk of electrolyte leakage of the battery cell, and ensuring the sealing requirement of the battery cell, thereby prolonging the service life and improving the safety of the battery cell.

Description

Cell cover and cell

[0001] Cross-references to related applications

[0002] This application claims priority to Chinese Patent Application No. CN202410693648.5, filed on May 31, 2024, entitled "Cell Cover and Cell", the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of battery technology, and in particular to a cell cover and a cell. Background Technology

[0004] With the increasing maturity of lithium-ion battery technology, lithium-ion batteries are widely used as power batteries in electric vehicles and energy storage, and the requirements for the performance and safety of lithium-ion batteries are becoming increasingly stringent.

[0005] Currently, a battery cell mainly consists of a cover plate, a housing, electrode groups, end plates, side plates, bare cell insulating sheets, and electrode groups. The cover plate and housing, after welding, form a sealed space that protects the electrode groups and provides a certain level of mechanical strength. The side plates and bare cell insulating sheets are welded and fixed to the outside of the electrode groups. The bare cell insulating sheets are fused to the plastic parts on the cover plate, thus fixing the electrode groups inside the housing and preventing short circuits. An explosion-proof valve is installed on the cover plate to promptly release pressure and expel gas from the housing in case of cell failure, ensuring safe use of the battery cell.

[0006] When the explosion-proof valve on the cover plate is located at the bottom of the battery pack, a cavity is formed inside the cell, consisting of an end plate, the explosion-proof valve, and plastic parts. The electrolyte inside the cell will accumulate in the cavity. When the battery moves with the electric vehicle or is subjected to vibration, the electrolyte will slosh around in the cavity, causing the electrolyte to continuously impact the explosion-proof valve. This can easily damage and crack the explosion-proof valve, leading to cell leakage, premature opening of the explosion-proof valve, and other issues, affecting the cell's lifespan and safety.

[0007] Application content

[0008] In view of this, the purpose of this application is to provide a cell cover and a cell to solve the problem that when the explosion-proof valve on the existing cover is located at the bottom of the cell, the electrolyte inside the cell will accumulate on one side of the explosion-proof valve. When the battery moves with the electric vehicle or is subjected to vibration, the electrolyte will shake back and forth and continuously impact the explosion-proof valve, causing damage and cracking of the explosion-proof valve. This can easily lead to cell leakage, premature opening of the explosion-proof valve, and other problems, thereby affecting the service life and safety of the cell.

[0009] One object of this application is to provide a battery cell cover plate, wherein the battery cell cover plate comprises:

[0010] The top cover has mounting holes that penetrate its main body;

[0011] A pressure relief assembly is disposed in the mounting hole, the length dimension of the pressure relief assembly in the first direction is M, and the width dimension of the pressure relief assembly in the second direction is N;

[0012] A separator is disposed on the side of the top cover facing the cell housing and covers the mounting hole to separate the pressure relief assembly from the electrolyte inside the cell housing.

[0013] Beneficial effects: By setting a separator on the side of the top cover facing the cell housing, the pressure relief assembly and the electrolyte inside the cell housing are separated. Even if the electrolyte sloshes back and forth inside the cell housing, it cannot directly impact the pressure relief assembly. Instead, the force is applied to the separator, thus effectively buffering the impact force of the electrolyte. This prevents the pressure relief assembly from opening prematurely due to the impact of the electrolyte, ensuring that the pressure relief assembly opens normally under the set pressure and meets the working requirements of the cell. In addition, it can reduce the incidence of damage and cracking of the pressure relief assembly, thereby reducing the risk of electrolyte leakage, ensuring the sealing requirements of the cell electrolyte, and improving the service life and safety of the cell.

[0014] In one alternative embodiment, the separator is formed as a sheet-like structure;

[0015] And / or, the thickness t of the separator is 0.03mm ≤ t ≤ 0.3mm.

[0016] In one alternative embodiment, the separator is spaced apart from the pressure relief assembly;

[0017] The distance m between the separator and the pressure relief assembly is 0.2mm ≤ m ≤ 1mm.

[0018] In one alternative embodiment, the separator is provided with a buffer portion, which is formed as a cut structure, so that the separator can deform when it is impacted by the electrolyte.

[0019] In one optional embodiment, the buffer portion is formed as a strip structure extending along the plane of the separator, the length dimension of the strip structure is L1, the dimension of the separator in the length direction of the strip structure is L2, and L1 / L2=L1 / (M+4)=0.2~0.6;

[0020] And / or, the buffer portion is located at the middle position of the separator.

[0021] In one optional embodiment, the buffer portion is formed as a structure with multiple through holes spaced apart, the total area of ​​the buffer portion is S1, the area of ​​the separator is S2, and S1 / S2 = S1 / [π×(N+4)]. 2 / 4+(MN)×(N+4)]=0.3~0.6.

[0022] In one alternative implementation, the separator is a flexible element;

[0023] And / or, the separator is a corrosion-resistant component.

[0024] In one optional implementation, the pressure relief assembly includes:

[0025] An explosion-proof patch is disposed on the side of the top cover plate facing away from the cell housing;

[0026] An explosion-proof valve is embedded inside the mounting hole.

[0027] In one optional embodiment, the mounting hole is formed as a stepped structure, and the mounting hole includes a first mounting part, a second mounting part and a third mounting part arranged sequentially along its axial direction, wherein the maximum length of the first mounting part in the extension direction of the top cover piece is less than the maximum length of the second mounting part in the extension direction of the top cover piece and the maximum length of the third mounting part in the extension direction of the top cover piece.

[0028] The explosion-proof valve is embedded in the second mounting part, the explosion-proof patch is attached to the end of the first mounting part, and the separator is attached to the end of the third mounting part;

[0029] And / or, the cell cover plate further includes:

[0030] A lower insulating member is disposed on the side of the top cover plate facing the cell housing, and a separator is sandwiched between the top cover plate and the lower insulating member.

[0031] Another object of this application is to provide a battery cell including the battery cell cover plate described in any of the above technical solutions. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0033] Figure 1 is an exploded view of the battery cell cover plate provided in an embodiment of this application;

[0034] Figure 2 is a partially enlarged schematic diagram of the cell cover plate provided in an embodiment of this application;

[0035] Figure 3 is a schematic diagram of the assembly of the cell cover and the cell housing provided in an embodiment of this application;

[0036] Figure 4 is an enlarged schematic diagram of the structure at point A in Figure 3;

[0037] Figure 5 is a schematic diagram of the structure of the buffer section of the battery cell cover provided in the embodiment of this application, which is a strip structure, from a first perspective;

[0038] Figure 6 is a schematic diagram of the structure of the buffer section of the battery cell cover provided in the embodiment of this application, which is a strip structure, from a second perspective;

[0039] Figure 7 is a schematic diagram of the structure of the buffer section of the battery cell cover plate provided in the embodiment of this application, which is a strip structure, from a third-person perspective;

[0040] Figure 8 is a schematic diagram of the structure of the separator with multiple through holes in the buffer part of the battery cell cover provided in the embodiment of this application;

[0041] Figure 9 is a schematic diagram of the pressure relief assembly in the cell cover provided in the embodiment of this application.

[0042] Explanation of reference numerals in the attached drawings: 10-Top cover plate; 11-Mounting hole; 111-First mounting part; 112-Second mounting part; 113-Third mounting part; 20-Pressure relief assembly; 21-Explosion-proof patch; 22-Explosion-proof valve; 30-Separator; 31-Buffer part; 41-Upper insulating part; 42-Lower insulating part; 50-End plate; 60-Cell housing; 70-Electrode post; 71-First electrode post part; 72-Second electrode post part; 80-Sealing part; 90-Electrode group; 100-Electrolyte; D1-First direction; D2-Second direction. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0044] According to a first aspect of this application, a cell cover plate is provided, which includes a top cover plate 10, a pressure relief assembly 20, and a separator 30.

[0045] The specific structure of the above-described components of the cell cover plate according to this embodiment will be described below.

[0046] In this embodiment, as shown in Figures 3, 4, and 9, the cell cover plate is assembled with the cell housing 60 to form a closed space inside. The electrode assembly 90 is disposed within the closed space. The top cover plate 10 has a mounting hole 11 that penetrates its main body. The pressure relief assembly 20 is disposed in the mounting hole 11. The shape of the mounting hole 11 is conformally adapted to the shape of the pressure relief assembly 20 to ensure that the pressure relief assembly 20 can close the mounting hole 11. Furthermore, when the cell is a blade cell or a square cell, the top cover plate 10 is formed into a rectangular structure; when the cell is a cylindrical cell, the top cover plate 10 is formed into a circular structure.

[0047] It should be noted that the side of the pressure relief assembly 20 facing the cell housing 60 must not be obstructed by any other structure to form a ventilation space. The end plate 50 presses against one end of the electrode assembly 90, so that the ventilation space has sufficient volume to ensure smooth gas ventilation. When the pressure relief assembly 20 is located at the bottom of the cell (for example, as shown in Figure 3, the cell cover is formed as a vertically arranged strip structure and the pressure relief component is located at one end of the length direction of the cell cover), at least a portion of the electrolyte 100 inside the cell is located in the ventilation space. When the cell shakes or is vibrated, the electrolyte 100 also reciprocates inside the cell.

[0048] In this embodiment, as shown in Figures 1 to 7, the separator 30 is disposed on the side of the top cover 10 facing the cell housing 60 and covers the mounting hole 11 to separate the pressure relief assembly 20 from the electrolyte 100 inside the cell housing 60. This allows the electrolyte 100 to directly contact the separator 30 without directly contacting the pressure relief assembly 20. Even if the electrolyte 100 oscillates back and forth inside the cell housing 60 as described above, it cannot directly impact the pressure relief assembly 20. Instead, the force is applied to the separator 30, thus effectively buffering the impact force of the electrolyte 100. This prevents the pressure relief assembly 20 from opening prematurely due to the impact of the electrolyte 100, ensuring that the pressure relief assembly 20 opens normally under the set pressure. Furthermore, it reduces the incidence of damage and cracking of the pressure relief assembly 20, thereby reducing the risk of electrolyte 100 leakage.

[0049] Specifically, in this embodiment, as shown in Figures 1 to 7, the separator 30 can be bonded to the side of the top cover 10 facing the cell housing 60. The separator 30 is formed as a sheet structure, for example, the separator 30 can be formed as a thin film structure. In the preferred embodiment, as shown in Figure 7, the thickness t of the separator 30 is 0.03mm≤t≤0.3mm. This ensures that the separator 30 can effectively withstand the impact of the electrolyte 100, and when the cell fails and generates high-pressure gas inside, it ensures that the high-pressure gas can break through or damage the connection between the separator 30 and the top cover 10, so as to ensure that the pressure relief assembly 20 can open normally under the set pressure and ensure the safety of the cell.

[0050] More specifically, in this embodiment, as shown in Figures 1 to 7, the separator 30 is a flexible component. That is, when the electrolyte 100 acts on the separator 30, the separator 30 can deform under the impact of the electrolyte 100, thus ensuring that the separator 30 has a certain ability to buffer the impact of the electrolyte 100, thereby improving the protective effect of the separator 30 on the pressure relief assembly 20. And / or, the separator 30 is a corrosion-resistant component, thus avoiding contact between the separator 30 and the electrolyte 100, which could lead to corrosion of the separator 30, further ensuring the reliability of the protective effect of the separator 30 on the pressure relief assembly 20. In one optional embodiment, the separator 30 is made of PC material, giving it both flexibility and corrosion resistance; in another optional embodiment, the separator 30 is made of PET material, which also satisfies the optimal choice between flexibility and corrosion resistance.

[0051] In this embodiment, as shown in Figures 2 to 4, the separator 30 and the pressure relief assembly 20 are spaced apart. This avoids direct contact between the separator 30 and the pressure relief assembly 20, which could lead to the separator 30 easily transmitting force to the pressure relief assembly 20 when the separator 30 is impacted by the electrolyte 100. This improves the reliability of the protective effect of the separator 30 on the pressure relief assembly 20. In a preferred embodiment, as shown in Figure 2, the distance m between the separator 30 and the pressure relief assembly 20 is 0.2mm ≤ m ≤ 1mm. This creates a buffer space between the separator 30 and the pressure relief assembly 20 to allow the separator 30 to deform under the impact of the electrolyte 100 without increasing the thickness of the top cover 10 or affecting the overall size of the assembled battery cell.

[0052] Furthermore, in this embodiment, as shown in Figures 5 to 7, a buffer portion 31 is provided on the separator 30. The buffer portion 31 is formed with a slit structure, which allows the separator 30 to deform more easily when impacted by the electrolyte 100, thereby playing a certain buffering role and effectively absorbing the impact from the electrolyte 100, improving the protective effect of the separator 30. Importantly, the buffer portion 31 ensures that when the cell fails and the gas pressure inside the cell housing 60 increases, the gas can quickly rush to the pressure relief assembly 20 through the buffer portion 31, ensuring timely pressure relief, guaranteeing cell safety, and preventing the separator 30 from detaching from the top cover 10 under high pressure and attaching to the pressure relief assembly 20, which would prevent the pressure relief assembly 20 from opening normally.

[0053] Specifically, the cut structure can be formed by a cutter engraving along a preset trajectory on the separator 30, so that the width of the buffer part 31 is very small. In this way, while ensuring that the separator 30 can be easily deformed to buffer the electrolyte 100, it can also ensure that the separator 30 reliably separates the electrolyte 100 and the pressure relief assembly 20.

[0054] Furthermore, in an optional embodiment, as shown in Figures 5 to 7, the buffer portion 31 is formed as a strip structure extending along the plane of the separator 30, ensuring that the width of the buffer portion 31 is much smaller than the length of the buffer portion 31, so as to improve the reliability of blocking the electrolyte 100 from impacting the pressure relief assembly 20. The buffer portion 31 can extend along the length direction of the separator 30 or along the width direction of the separator 30. In a preferred embodiment, the buffer portion 31 is located in the middle position of the separator 30, so as not to affect the connection between the separator 30 and the top cover plate 10, and to ensure that the internal gas can be smoothly discharged from the buffer portion 31 under high pressure.

[0055] Further, as shown in Figures 6 and 9, the length of the buffer section 31 of the strip structure is L1, and the dimension of the separator 30 in the length direction of the strip structure is L2. Preferably, L1 / L2 = L1 / (M+4) = 0.2~0.6, where M is the length of the pressure relief assembly 20 in the first direction D1. This avoids the situation where L1 is too short, leading to an increase in the actual opening pressure of the pressure relief assembly 20 and compromising effective protection, or where L1 is too long, causing the electrolyte to easily breach the pressure relief assembly 20. In this embodiment, the length direction of the buffer section 31 is the first direction D1 of the pressure relief assembly 20.

[0056] The following experimental verification is conducted under the constraint that L1 / L2 = L1 / (M+4) = 0.2 to 0.6:

[0057] Experiment 1: The length of the pressure relief assembly 20 in the first direction D1 is M = 20 mm, and the corresponding length of L2 is 24 mm. The preset opening pressure of the pressure relief assembly 20 is 0.6 ± 0.2 MPa. The test results are shown in Table 1.

[0058] Table 1

[0059] Test 2: The length of the pressure relief assembly 20 in the first direction D1 is M = 25 mm, and the corresponding length of L2 is 29 mm. The preset opening pressure of the pressure relief assembly 20 is 0.6 ± 0.2 MPa. The test results are shown in Table 2.

[0060] Table 2

[0061] Test 3: The length of the pressure relief assembly 20 in the first direction D1 is M = 30 mm, and the corresponding length of L2 is 34 mm. The preset opening pressure of the pressure relief assembly 20 is 0.9 ± 0.2 MPa. The test results are shown in Table 3.

[0062] Table 3

[0063] As shown in Tables 1 to 3, in Examples 1-1, 1-2, 2-1, 2-2, 3-1, and 3-2, L1 / L2 is less than 0.2. The actual opening pressure of the pressure relief component 20 is greater than the preset opening pressure. This is because the length of L1 is too short, causing the pressure relief component 20 to fail to open in time, thus failing to ensure the safe use of the battery cell. In Examples 1-8, 1-9, 2-8, 2-9, 3-8, and 3-9, L1 / L2 is greater than 0.6. Although the actual opening pressure of the pressure relief component 20 meets the preset requirements, there is still a situation where the electrolyte pushes the pressure relief component 20 open. This is because the length of L1 is too long, causing the separator 30 to fail to effectively form protection.

[0064] Referring to Tables 1 to 3, it can be seen that Examples 1-3 to 1-7, Examples 2-3 to 2-7, and Examples 3-3 to 3-7 can all simultaneously satisfy the condition that the electrolyte 100 will not open the pressure relief component 20 and that the actual opening pressure of the pressure relief component 20 is within the range of the preset opening pressure. Therefore, it is proved that the limiting condition of L1 / L2=L1 / (M+4)=0.2~0.6 can ensure that the separator 30 plays a good role in buffering the impact force of the electrolyte 100, thereby avoiding the situation that the pressure relief component 20 will open prematurely under the impact of the electrolyte, and ensuring that the pressure relief component 20 opens normally under the set pressure.

[0065] In another optional embodiment, as shown in Figures 8 and 9, the buffer portion 31 is formed as a structure with multiple through holes spaced apart. The shape of the through holes can be circular or rectangular, etc. The multiple through holes can be arranged linearly, annularly, or in a rectangular array. The total area of ​​the buffer portion 31 is S1, that is, S1 is the sum of the areas of all the through holes. The area of ​​the separator 30 is S2, that is, S2 is the area of ​​the region enclosed by the outer edge of the separator 30, that is, not the area after removing S1; preferably, S1 / S2 = S1 / [π×(N+4)]. 2 / 4+(MN)×(N+4)]=0.3~0.6, where M is the length dimension of the pressure relief component 20 in the first direction D1, and N is the width dimension of the pressure relief component 20 in the second direction D2. This avoids S1 being too small, which would increase the actual opening pressure of the pressure relief component 20 and fail to guarantee effective protection, or S1 being too large, which would make it easy for the electrolyte to push open the pressure relief component 20. Thus, when the cell produces gas to the preset pressure, it can ensure that the pressure relief component 20 opens smoothly, and at the same time, it can alleviate the impact of the electrolyte on the pressure relief component 20 when the cell shakes, and prevent the pressure relief component 20 from opening prematurely.

[0066] In this embodiment, the first direction D1 is perpendicular to the second direction D2, and the pressure relief component 20 is formed as an elliptical structure with a rectangular middle section and semicircular sides on the first direction D1.

[0067] The following discussion concerns S1 / S2 = S1 / [π×(N+4)]. 2 The experiment was conducted to verify the condition that [ / 4+(MN)×(N+4)]=0.3~0.6.

[0068] Test 4: The length dimension M of the pressure relief assembly 20 in the first direction D1 is 20mm, and the width dimension N of the pressure relief assembly 20 in the second direction D2 is 8.5mm, correspondingly S2 = 266.5mm. 2 The preset opening pressure of the pressure relief component 20 is 0.9±0.2 MPa. The test results are shown in Table 4.

[0069] Table 4

[0070] Test 5: The length of the pressure relief assembly 20 in the first direction D1 is M = 24 mm, and the width of the pressure relief assembly 20 in the second direction D2 is N = 9 mm, corresponding to S2 = 327.7 mm. 2 The preset opening pressure of the pressure relief component 20 is 0.9±0.2 MPa. The test results are shown in Table 5.

[0071] Table 5

[0072] Test 6: The length of the pressure relief assembly 20 in the first direction D1 is M = 24 mm, the width of the pressure relief assembly 20 in the second direction D2 is N = 12 mm, and the corresponding S2 = 393 mm. 2 The preset opening pressure of the pressure relief component 20 is 0.6±0.2 MPa. The test results are shown in Table 6.

[0073] Table 6

[0074] Referring to Tables 4 to 6, in Examples 4-1, 4-2, 5-1, 5-2, 6-1, and 6-2, S1 / S2 is less than 0.3, and the actual opening pressure of the pressure relief component 20 is greater than the preset opening pressure. This is because S1 is too small, causing the pressure relief component 20 to fail to open in time, thus failing to ensure the safe use of the battery cell. In Examples 4-7, 4-8, 5-7, 5-8, 6-7, and 6-8, S1 / S2 is greater than 0.6. Although the actual opening pressure of the pressure relief component 20 meets the preset requirements, there is still a situation where the electrolyte pushes the pressure relief component 20 open. This is because S1 is too large, causing the separator 30 to fail to effectively form protection.

[0075] Referring to Tables 4 to 6, it can be seen that Examples 4-3 to 4-6, Examples 5-3 to 5-6, and Examples 6-3 to 6-6 can all simultaneously satisfy the condition that the electrolyte 100 will not break open the pressure relief component 20 and that the actual opening pressure of the pressure relief component 20 is within the range of the preset opening pressure. Therefore, it is proven that S1 / S2=S1 / [π×(N+4)]. 2 The constraint of [ / 4+(MN)×(N+4)]=0.3~0.6 ensures that the separator 30 effectively buffers the impact of the electrolyte 100, thereby preventing the pressure relief assembly 20 from opening prematurely due to the impact of the electrolyte and ensuring that the pressure relief assembly 20 opens normally under the set pressure.

[0076] Furthermore, in this embodiment, as shown in Figures 1 to 4, the pressure relief assembly 20 includes an explosion-proof patch 21 and an explosion-proof valve 22. The explosion-proof patch 21 is disposed on the side of the top cover 10 facing away from the battery cell housing 60; the explosion-proof valve 22 is embedded inside the mounting hole 11, and the explosion-proof patch 21 can protect the explosion-proof valve 22.

[0077] Further, in this embodiment, as shown in Figures 1 to 4, the mounting hole 11 is formed into a stepped structure. Specifically, the mounting hole 11 includes a first mounting portion 111, a second mounting portion 112, and a third mounting portion 113 arranged sequentially along its axial direction. The maximum length of the first mounting portion 111 in the extending direction of the top cover plate 10 is less than the maximum length of the second mounting portion 112 in the extending direction of the top cover plate 10, and less than the maximum length of the third mounting portion 113 in the extending direction of the top cover plate 10. The first mounting part 111 is located on the side away from the cell housing 60, and the third mounting part 113 is located on the side closer to the cell housing 60. The explosion-proof valve 22 is embedded in the second mounting part 112, the explosion-proof patch 21 is attached to the end of the first mounting part 111, and the separator 30 is attached to the end of the third mounting part 113. This arrangement of the explosion-proof patch 21, the explosion-proof valve 22, and the separator 30 at intervals satisfies the protection requirements of the explosion-proof patch 21 and the separator 30 for the explosion-proof valve 22, and facilitates the assembly of the cell cover plate. In this embodiment, the extending direction of the top cover plate 10 is the length direction of the top cover plate 10.

[0078] In this embodiment, as shown in Figures 1 to 4, the cell cover plate further includes a terminal post 70, an upper insulating member 41, and a lower insulating member 42. The top cover plate 10 has a through hole for mounting the terminal post 70. The terminal post 70 includes a positive terminal post and a negative terminal post. The positive terminal post is connected to the positive tab on the electrode assembly 90, and the negative terminal post is connected to the negative tab on the electrode assembly 90. In this embodiment, as shown in Figures 1 and 3, the terminal post 70 is formed as a split structure to facilitate assembly of the terminal post 70 with the top cover plate 10. Specifically, the terminal post 70 includes... The first electrode post 71 and the second electrode post 72 are located on the side of the cell cover plate away from the cell housing 60, and the second electrode post 72 are located on the side of the cell cover plate close to the cell housing 60. The second electrode post 72 has a connecting part that protrudes towards the first electrode post 71, so that the first electrode post 71 and the second electrode post 72 are connected. The top cover plate 10 is sandwiched between the first electrode post 71 and the second electrode post 72. The first electrode post 71 and the second electrode post 72 can be connected by riveting.

[0079] It should be noted that when the cell is a blade cell, the cell cover includes a positive cover and a negative cover. The positive electrode tab is set on the positive cover, and the negative cover is set on the negative cover. At least one of the positive cover and the negative cover is provided with a pressure relief component 20, and the separator 30 is provided with the pressure relief component 20. When the cell is a square cell, the positive electrode tab, the negative electrode tab, and the pressure relief component 20 can be set on the same cell cover.

[0080] Further, as shown in Figure 1, the upper insulating member 41 is disposed between the first electrode post 71 and the top cover plate 10. The upper insulating member 41 tightly covers part of the outer wall of the first electrode post 71, ensuring the reliability of the insulation between the electrode post 70 and the top cover plate 10. Even further, as shown in Figures 1 to 4, the lower insulating member 42 is disposed on the side of the top cover plate 10 facing the cell housing 60. The separator 30 is sandwiched between the top cover plate 10 and the lower insulating member 42. The two side surfaces of the separator 30 are in contact with the top cover plate 10 and the lower insulating member 42 respectively, ensuring reliable installation of the separator 30. Both the upper insulating member 41 and the lower insulating member 42 are formed by plastic injection molding to provide insulation.

[0081] It should be noted that, without the partition 30 (i.e., in the prior art), the ventilation space described above is formed by the end plate, the explosion-proof valve, and the lower insulating component; in this embodiment, the ventilation space is formed by the end plate 50, the partition 30, and the lower insulating component 42, thereby ensuring that when the electrolyte 100 enters the ventilation space, the partition 30 can prevent the electrolyte 100 from directly contacting the pressure relief component 20.

[0082] In addition, in this embodiment, as shown in Figures 1 to 4, the cell cover plate also includes a sealing element 80. The sealing element 80 can be formed as a sealing ring with an annular structure. Part of the sealing element 80 is sandwiched between the pole post 70 and the top cover plate, and part of the sealing element 80 is sandwiched between the lower insulating member 42 and the pole post 70, thereby ensuring the sealing performance of the cell cover plate.

[0083] The following tests are conducted on the battery cell formed by assembling the battery cell cover plate with the separator 30 in this embodiment with the battery cell cover plate without the separator in the prior art, to verify whether the separator 30 has an effective function of buffering the impact force of the electrolyte:

[0084] Test 7: The length dimension M of the pressure relief assembly 20 in the first direction D1 is 20mm, and the width dimension N of the pressure relief assembly 20 in the second direction D2 is 8.5mm. The test results are shown in Table 7.

[0085] Table 7

[0086] Test 8: The length dimension M of the pressure relief assembly 20 in the first direction D1 is 25mm, and the width dimension N of the pressure relief assembly 20 in the second direction D2 is 10mm. The test results are shown in Table 8.

[0087] Table 8

[0088] Test 9: The length dimension M of the pressure relief assembly 20 in the first direction D1 is 28mm, and the width dimension N of the pressure relief assembly 20 in the second direction D2 is 12mm. The test results are shown in Table 9.

[0089] Table 9

[0090] As can be seen from Tables 7 to 9, for pressure relief components 20 of different sizes and with different preset opening pressures, the actual opening pressure parameter of the pressure relief component 20 with the separator 30 is close to the preset opening pressure, while the actual opening pressure of the pressure relief component without the separator 30 is significantly lower than the preset opening pressure. Therefore, it is proven that the cell cover plate with the separator 30 has the effect of effectively buffering the impact force of the electrolyte.

[0091] It should be noted that, in this embodiment, the preset opening pressure of the pressure relief component 20 in tests one through nine is expressed as: theoretically, when the internal pressure of the battery cell increases to this parameter, the pressure relief component 20 needs to open in time to connect the inside and outside of the battery cell, thereby releasing the internal pressure of the battery cell to ensure the safe use of the battery cell. Therefore, the preset opening pressure of the pressure relief component 20 is the judgment standard for detecting the safety of the battery cell; the actual opening pressure of the pressure relief component 20 in Tables 1 through 9 is expressed as: the actual opening parameter of the pressure relief component 20 when the battery cell is pressurized during the test; when the pressure relief component 20 opens, the pressure relief component 20 opens ... If the actual opening parameters of the pressure relief component 20 (i.e., the actual opening pressure of the pressure relief component 20) are within the range of the set parameters (i.e., the preset opening pressure of the pressure relief component 20) required to ensure the safe use of the battery cell, the test is considered qualified. If the actual parameters are less than the set parameters, it means that the pressure relief component 20 opens prematurely, which is mainly due to the impact of the electrolyte on the pressure relief component 20. If the actual parameters are greater than the set parameters, it means that the opening time of the pressure relief component 20 is relatively delayed, which may be due to the separator 30 preventing the pressure inside the battery cell from breaking through the pressure relief component 20, thus failing to guarantee the safety requirements for the use of the battery cell.

[0092] It should be further noted that in Experiments 1 to 9 of this embodiment, the specifications and production batches of the battery cells tested in different embodiments within the same group of experiments are the same, in order to improve the accuracy of the test results. For example, taking Experiment 7 as an example, the difference between the battery cell cover plate with the separator 30 and the two battery cell cover plates without the separator in Example 7-1 is only the presence or absence of the separator 30. Furthermore, the specifications and production batches of all battery cells used for testing in Examples 7-1 to 7-5 are the same.

[0093] According to the battery cell cover provided in this application, a separator is provided on the side of the top cover facing the battery cell housing to separate the pressure relief assembly from the electrolyte inside the battery cell housing. Even if the electrolyte sloshes back and forth inside the battery cell housing, the electrolyte cannot directly impact the pressure relief assembly, but instead acts on the separator. This effectively buffers the impact force of the electrolyte, thereby preventing the pressure relief assembly from opening prematurely due to the impact of the electrolyte and ensuring that the pressure relief assembly opens normally under the set pressure. In addition, it can also reduce the incidence of damage and cracking of the pressure relief assembly, thereby reducing the risk of electrolyte leakage.

[0094] According to the second aspect of this application, a battery cell includes the aforementioned battery cell cover plate, which is welded to the battery cell housing. A separator is provided on the side of the battery cell cover plate facing the battery cell housing to prevent direct contact between the electrolyte and the pressure relief component. This effectively buffers the impact force of the electrolyte, ensuring that the pressure relief component opens normally under the set pressure, meeting the battery cell's operating requirements and providing effective protection for the battery cell. In addition, it reduces the risk of electrolyte leakage, ensures the sealing requirements of the battery cell's electrolyte, and improves the battery cell's service life and safety.

[0095] Although embodiments of this application have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of this application, and all such modifications and variations fall within the scope defined by the appended claims. Industrial applicability

[0096] The cell cover of this application separates the pressure relief assembly from the electrolyte inside the cell housing by setting a separator on the side of the top cover facing the cell housing. Even if the electrolyte sloshes back and forth inside the cell housing, the electrolyte cannot directly impact the pressure relief assembly. Instead, the force is applied to the separator, thus effectively buffering the impact force of the electrolyte. This prevents the pressure relief assembly from opening prematurely due to the impact of the electrolyte, ensuring that the pressure relief assembly opens normally under the set pressure. In addition, it can also reduce the incidence of damage and cracking of the pressure relief assembly, thereby reducing the risk of electrolyte leakage.

Claims

1. An electrode cover plate, characterized by, The electric core cover plate comprises: a top cover sheet, which is provided with a mounting hole penetrating through the main body thereof; a pressure relief assembly arranged in the mounting hole, the length of the pressure relief assembly in a first direction being M, and the width of the pressure relief assembly in a second direction being N; a partition arranged on the side of the top cover sheet facing the electric core shell and covering the mounting hole to separate the pressure relief assembly and the electrolyte in the electric core shell; a buffer part is arranged on the partition, the buffer part is formed in a notch structure, so that the partition can be deformed when impacted by the electrolyte; the buffer part is formed in a strip structure extending along the plane of the partition, the length of the strip structure being L1, the dimension of the partition in the length direction of the strip structure being L2, L1 / L2=L1 / (M+4)=0.2-0.6; Or the buffer part is formed as a structure of multiple through holes arranged at intervals, the total area of the buffer part is S1, the area of the partition is S2, S1 / S2=S1 / [π×(N+4) 2 / 4+(M-N)×(N+4)]=0.3~0.

6.

2. The cell cover plate of claim 1, wherein, the partition is formed in a sheet structure; and / or, the thickness t of the partition is 0.03mm≤t≤0.3mm.

3. The cell cover plate of claim 1, wherein, The partition is arranged at a distance from the pressure relief assembly; the distance m between the partition and the pressure relief assembly is 0.2mm≤m≤1mm.

4. The cell cover plate of claim 1, wherein, The buffer part is arranged at the middle position of the partition.

5. The cell cover plate of claim 1, wherein, The partition is a flexible part.

6. The cell cover plate of claim 1, wherein, The partition is a corrosion-resistant part.

7. The cell cover plate of claim 1, wherein, The pressure relief assembly comprises: an explosion-proof patch arranged on the side of the top cover sheet away from the electric core shell; an explosion-proof valve embedded in the inside of the mounting hole.

8. The cell cover plate of claim 7, wherein, The mounting hole is formed in a stepped structure, the mounting hole comprises a first mounting part, a second mounting part and a third mounting part arranged in sequence along the axial direction thereof, the maximum length of the first mounting part in the extension direction of the top cover sheet < the maximum length of the second mounting part in the extension direction of the top cover sheet < the maximum length of the third mounting part in the extension direction of the top cover sheet; the explosion-proof valve is embedded in the second mounting part, the explosion-proof patch is attached to the end of the first mounting part, and the partition is attached to the end of the third mounting part.

9. The cell cover plate of claim 1, wherein, The electric core cover plate further comprises: a lower insulating part arranged on the side of the top cover sheet facing the electric core shell, and the partition is clamped between the top cover sheet and the lower insulating part.

10. An electric cell characterized by, comprising the electric core cover plate according to any one of claims 1 to 9.

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