Cover plate and battery cell

Abstract

The application relates to the technical field of batteries, in particular to a cover plate and a battery cell. The cover plate comprises an insulating plastic part, a cover plate body, a supporting plate and a first insulating film. The insulating plastic part is arranged on one side of the cover plate body, and the cover plate body is provided with an explosion-proof valve. The side of the cover plate body facing the insulating plastic part is provided with a supporting protrusion protruding to the side where the insulating plastic part is located, the supporting plate is connected with the supporting protrusion to form a ventilation gap with the cover plate body. One side of the insulating plastic part is attached to the cover plate body, and the other side is used to be attached to a pole group. In the thickness direction, the insulating plastic part is provided with a window penetrating through the insulating plastic part, the supporting plate penetrates through the window, the first insulating film is attached to the supporting plate and is flush with the side of the insulating plastic part facing away from the cover plate body. The application solves the problem that in the existing energy storage battery cell, under the impact of high-temperature and high-pressure airflow inside the battery cell, the pole group will move to the side of the explosion-proof valve, causing the front end of the pole group to block the explosion-proof valve and the space size occupied by the battery cell cover plate to be large.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a cover plate and a battery cell. Background Technology

[0002] Lithium-ion batteries are widely used in various fields such as transportation power supplies, power storage, new energy storage power supplies, and aerospace and military industries due to their advantages such as large capacity, high operating voltage, strong charge retention, and long cycle life. Existing energy storage cell structures generally include a cover plate (including aluminum plates and plastic parts), a casing, a bare cell insulating film, electrode assembly, and electrolyte. The plastic parts primarily serve as insulation and protection, and for heat-melting to fix the bare cell insulating film.

[0003] Energy storage cells generally have large capacities and higher safety requirements. Blade energy storage cells typically have electrodes on the same side, with the explosion-proof valve on the opposite side cover plate to achieve thermal-electric separation and improve cell safety. However, in the event of thermal runaway, the explosion-proof valve opens to release pressure and exhaust air. Under the impact of the high-temperature, high-pressure airflow inside the cell (after the plastic parts melt), the electrode assembly can move towards the explosion-proof valve side, causing the front end of the electrode assembly to block the valve. This significantly reduces the venting effect of the explosion-proof valve and lowers the cell's safety performance. Furthermore, the cover plate of existing blade energy storage cells occupies a large space after assembly, affecting the cell's energy density. Summary of the Invention

[0004] The purpose of this application is to provide a cover plate and a battery cell, thereby solving the problem that in existing energy storage battery cells, under the impact of high temperature and high pressure airflow inside the battery cell (after the plastic parts melt), the electrode assembly will move towards the explosion-proof valve side, resulting in the front end of the electrode assembly blocking the explosion-proof valve and the battery cell cover plate occupying a large space.

[0005] According to a first aspect of this application, a cover plate is provided, the cover plate having a thickness direction, the cover plate including an insulating plastic part, a cover plate body, a support plate and a first insulating film, the insulating plastic part being disposed on one side of the cover plate body in the thickness direction, the cover plate body being provided with an explosion-proof valve; a support protrusion protruding towards the side of the insulating plastic part is provided on the side of the cover plate body facing the insulating plastic part, the support plate being connected to the support protrusion to form an air gap with the cover plate body; one side of the insulating plastic part in the thickness direction is fitted to the cover plate body, and the other side is used to fit with an electrode assembly; along the thickness direction, the insulating plastic part is provided with a through-hole, the support plate passing through the through-hole, the first insulating film being attached to the support plate and flush with the side of the insulating plastic part facing away from the cover plate body; the support plate, the explosion-proof valve and the through-hole are arranged facing each other in the thickness direction.

[0006] In any of the above technical solutions, further, the thickness t2 of the first insulating film is 0.2mm-0.5mm, the first insulating film includes an insulating film layer and an adhesive layer, and the first insulating film is adhered to the support plate by its own adhesive layer; and / or, the support plate has a vent hole that penetrates itself, and the first insulating film has a through hole that penetrates itself, and the positions of the through hole and the vent hole correspond one-to-one.

[0007] In any of the above technical solutions, the cover plate further includes a length direction perpendicular to the thickness direction, and the insulating plastic part includes a first support portion, an exhaust portion, and a second support portion connected sequentially along the length direction. The first support portion and the second support portion have the same structure, and the window is opened in the exhaust portion. In the thickness direction, the first support portion and the second support portion protrude from the side opposite to the cover plate body relative to the exhaust portion, and the first insulating film is flush with the side of the first support portion and the second support portion opposite to the cover plate body. In the thickness direction, the exhaust portion is flush with the side of the first support portion and the second support portion facing the cover plate body.

[0008] In any of the above technical solutions, the first support portion and the second support portion both include a bottom wall and an eaves surrounding the edge of the bottom wall. The first support portion and the second support portion form an exhaust groove that opens to one side of the cover plate body. The bottom wall has an exhaust hole that penetrates itself. In the thickness direction, the side of the exhaust portion facing the cover plate body is flush with the eaves. The eaves of the first support portion and the eaves of the second support portion both have exhaust notches on opposite sides in the length direction. The side of the exhaust notch facing the cover plate body is open. The exhaust notch connects the exhaust groove and the window.

[0009] In any of the above technical solutions, the opening extends to the eaves of the first support and the second support respectively at the two opposite ends in the length direction; and / or, a reinforcing rib extending toward the side of the cover plate body is provided on the side of the bottom wall facing the cover plate body, and the reinforcing rib is lower than the eaves in the thickness direction.

[0010] In any of the above technical solutions, the cover plate further includes a width direction, and the length direction, width direction and thickness direction are perpendicular to each other; the dimensions of the first support part, the second support part and the exhaust part are equal in the width direction, and the cover plate satisfies: 3mm≤(B-W2) / 2≤5mm, where B is the dimension of the insulating plastic part in the width direction and W2 is the dimension of the window in the width direction.

[0011] In any of the above technical solutions, the cover plate further includes a width direction, and the length direction, the width direction, and the thickness direction are perpendicular to each other; the dimensions of the first support part, the second support part, and the exhaust part are equal in the width direction, and the cover plate satisfies: 0.45≤L2 / A≤0.55, where A is the dimension of the insulating plastic part in the length direction, and L2 is the dimension of the window in the length direction.

[0012] In any of the above technical solutions, the cover plate further includes a width direction, and the length direction, width direction, and thickness direction are perpendicular to each other; the cover plate satisfies: 2mm≤(L2-L1) / 2≤4mm, 2mm≤(W2-W1) / 2≤4mm, where L2 is the dimension of the opening in the length direction, L1 is the dimension of the support plate in the width direction, W2 is the dimension of the opening in the width direction, and W1 is the dimension of the support plate in the width direction.

[0013] In any of the above technical solutions, further, the number of the supporting protrusions is multiple, and the multiple supporting protrusions are arranged around the edge of the supporting plate. The size of the supporting protrusions in the thickness direction is between 2mm and 3mm. The wall thickness of the supporting plate in the thickness direction is t = 0.8mm-1.5mm, and the wall thickness of the exhaust part in the thickness direction is h = 1mm-1.5mm.

[0014] According to a second aspect of this application, a battery cell is provided, including a cover plate as described above. The battery cell further includes an electrode assembly and a second insulating film. The electrode assembly includes an outer side surface and an end surface in the thickness direction. The end surface of the electrode assembly is in contact with the first support portion, the second support portion, and the first insulating film. The second insulating film covers the outer side surface of the electrode assembly. One end of the second insulating film in the thickness direction is open, and one end of the second insulating film in the thickness direction is fixedly connected to the edge.

[0015] The cover plate of this application includes an insulating plastic part, a cover plate body, a support plate, and a first insulating film. The insulating plastic part is disposed on one side of the cover plate body in the thickness direction, and the cover plate body is provided with an explosion-proof valve. A support protrusion protruding towards the insulating plastic part is provided on the side of the cover plate body facing the insulating plastic part. The support plate is connected to the support protrusion to form a ventilation gap with the cover plate body. One side of the insulating plastic part in the thickness direction is attached to the cover plate body, and the other side is used to attach to the electrode assembly. Along the thickness direction, the insulating plastic part has a through-hole, through which the support plate passes. The first insulating film is attached to the support plate and is flush with the side of the insulating plastic part facing away from the cover plate body. The support plate, the explosion-proof valve, and the through-hole are arranged facing each other in the thickness direction.

[0016] Based on the above technical features, the beneficial effects of this application are as follows: The cover plate of this application has a built-in explosion-proof valve. The cover plate body is equipped with a support protrusion and is protected by a support plate, which serves to protect the explosion-proof valve and prevent it from being blocked by the electrode assembly when the insulating plastic parts melt during thermal runaway of the battery cell, thus affecting the venting effect. The support plate in this application prevents the electrode assembly from continuing to move towards the explosion-proof valve even if the insulating plastic parts melt, thus avoiding the electrode assembly's front end blocking the explosion-proof valve. Furthermore, the venting gap between the cover plate body and the support plate allows for venting, thereby improving the safety performance of the battery cell. The thermal runaway venting path of the battery cell in this application (in the early stage of thermal runaway, before the insulating plastic parts melt): battery cell interior - venting gap / window - explosion-proof valve, to meet the venting requirements.

[0017] Based on this, the support plate passes through the opening, and the first insulating film is flush with the side of the insulating plastic part facing away from the cover plate body. This reduces the total height of the insulating plastic part (dimension in the thickness direction), minimizing the occupied height space and increasing the cell capacity. In other words, the total height of the entire cover plate assembly (dimension in the thickness direction) = the total height of the cover plate body + support protrusion + support plate + first insulating film. That is, the insulating plastic part does not occupy extra space in the thickness direction (the length direction of the cell), thereby increasing the cell capacity. In addition, when the electrode assembly is assembled with the cover plate, one end of the electrode assembly is in contact with one side of the insulating plastic part (including the first insulating film), ensuring the insulation performance at the contact point between the electrode assembly and the support plate.

[0018] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 A schematic diagram showing the assembly structure of the cover plate according to an embodiment of this application is provided. Figure 2 A schematic diagram showing the assembly structure of the first insulating film and the support plate according to an embodiment of this application is provided. Figure 3 A schematic diagram of the overall structure of the cover plate according to an embodiment of this application is shown; Figure 4 Show Figure 3 Side view; Figure 5 A schematic diagram of the structure of an insulating plastic part according to an embodiment of this application is shown; Figure 6 Show Figure 5 Another structural diagram from another perspective; Figure 7 Show Figure 5 Side view; Figure 8 A schematic diagram showing the dimensions of a support plate according to an embodiment of this application; Figure 9 Show Figure 5 Top view.

[0021] Icons: 100 - Insulating plastic part; 110 - First support part; 120 - Exhaust part; 130 - Second support part; 121 - Window; 111 - Exhaust hole; 112 - Bottom wall; 113 - Edge; 114 - Exhaust notch; 115 - Exhaust groove; 200 - Cover plate body; 300 - Support plate; 310 - Vent hole; 400 - Support protrusion; 410 - Vent gap; 500 - Reinforcing rib; 600 - First insulating film; X - Length direction; Y - Width direction; Z - Thickness direction. Detailed Implementation

[0022] The following detailed embodiments are provided to help the reader gain a comprehensive understanding of the methods, apparatus, and / or systems described herein. However, various changes, modifications, and equivalents of the methods, apparatus, and / or systems described herein will be apparent after understanding the disclosure of this application. For example, the order of operations described herein is merely illustrative and is not limited to the order set forth herein; changes that will be apparent after understanding the disclosure of this application are possible, except for operations that must occur in a specific order. Furthermore, for clarity and brevity, descriptions of features known in the art may be omitted.

[0023] The features described herein may be implemented in different forms and should not be construed as being limited to the examples described herein. Rather, the examples described herein have been provided merely to illustrate some of the many feasible ways of implementing the methods, apparatus, and / or systems described herein that will be apparent upon understanding the disclosure of this application.

[0024] Throughout the specification, when an element (such as a layer, region, or substrate) is described as being "on" another element, "connected to" another element, "bonded to" another element, "on" another element, or "covering" another element, it may be directly "on" another element, "connected to" another element, "bonded to" another element, "on" another element, or "covering" another element, or there may be one or more other elements in between. In contrast, when an element is described as being "directly on" another element, "directly connected to" another element, "directly bonded to" another element, "directly on" another element, or "directly covering" another element, there may be no other elements in between.

[0025] As used herein, the term “and / or” includes any one of the relevant items listed and any combination of any two or more items.

[0026] Although terms such as “first,” “second,” and “third” may be used herein to describe individual components, assemblies, regions, layers, or parts, these components, assemblies, regions, layers, or parts are not limited by these terms. Rather, these terms are used only to distinguish one component, assembly, region, layer, or part from another. Therefore, without departing from the teachings of the examples described herein, the first component, assembly, region, layer, or part referred to as the second component, assembly, region, layer, or part may also be referred to as the second component, assembly, region, layer, or part.

[0027] For ease of description, spatial relation terms such as “above,” “upper,” “below,” and “lower” are used herein to describe the relationship between one element and another, as shown in the accompanying drawings. Such spatial relation terms are intended to include not only the orientation depicted in the drawings but also different orientations of the device during use or operation. For example, if the device in the drawings is flipped, an element described as being “above” or “upper” relative to another element will subsequently be “below” or “lower” relative to that other element. Therefore, the term “above” includes both “above” and “below” orientations depending on the spatial orientation of the device. The device may also be positioned in other ways (e.g., rotated 90 degrees or in other orientations), and the spatial relation terms used herein will be interpreted accordingly.

[0028] The terminology used herein is for the purpose of describing various examples only and is not intended to limit this disclosure. Unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. The terms “comprising,” “including,” and “having” enumerate the stated features, quantities, operations, components, elements, and / or combinations thereof, but do not exclude the presence or addition of one or more other features, quantities, operations, components, elements, and / or combinations thereof.

[0029] Variations in the shapes shown in the accompanying drawings may occur due to manufacturing techniques and / or tolerances. Therefore, the examples described herein are not limited to the specific shapes shown in the accompanying drawings, but include changes in shape that may occur during manufacturing.

[0030] The features of the examples described herein can be combined in various ways that will be apparent upon understanding the disclosure of this application. Furthermore, although the examples described herein have a wide variety of constructions, other constructions are possible, as will be apparent upon understanding the disclosure of this application.

[0031] The first aspect of this application provides a cover plate, thereby solving the problem in existing energy storage cells that, under the impact of high-temperature and high-pressure airflow inside the cell (after the plastic parts melt), the electrode assembly will move towards the explosion-proof valve side, resulting in the front end of the electrode assembly blocking the explosion-proof valve and the cell cover plate occupying a large space. The following will refer to... Figures 1 to 9 The cover plate described in some embodiments of this application will be described in detail below. For ease of description, the cover plate will be described as having a length direction X, a width direction Y, and a thickness direction Z that are perpendicular to each other.

[0032] like Figure 1 , Figure 2 and Figure 3As shown, the cover plate of this application includes an insulating plastic part 100, a cover plate body 200 (e.g., a plain aluminum plate), a support plate 300 (e.g., an aluminum part), and a first insulating film 600. The insulating plastic part 100 is disposed on one side of the cover plate body 200 in the thickness direction Z. The cover plate body 200 is provided with an explosion-proof valve (not shown in the figure). A support protrusion 400 (e.g., formed by stamping from the cover plate body 200) protruding towards the insulating plastic part 100 is provided on the side of the cover plate body 200 facing the insulating plastic part 100. The support plate 300 is connected to the support protrusion 400 to form a ventilation gap 410 between itself and the cover plate body 200. The side of the insulating plastic part 100 in the thickness direction Z is connected to the cover plate body 200. The body 200 is attached to the other side, and the other side is used to attach to the electrode assembly. Along the thickness direction Z, the insulating plastic part 100 is provided with a window 121 that penetrates through itself. The support plate 300 passes through the window 121 (with the plane perpendicular to the thickness direction Z as the projection plane, the projection outline of the support plate 300 is within the projection outline of the window 121). The first insulating film 600 is attached to the support plate 300 and is flush with the side of the insulating plastic part 100 that is opposite to the cover plate body 200. The support plate 300, the explosion-proof valve and the window 121 are arranged facing each other in the thickness direction Z.

[0033] With this configuration, the cover plate body 200 of this application has an integrated explosion-proof valve. The cover plate body 200 is equipped with a support protrusion 400 and is protected by a support plate 300, which serves to protect the explosion-proof valve. This prevents the explosion-proof valve from being blocked by the electrode assembly and affecting the venting effect when the insulating plastic part 100 melts during thermal runaway of the battery cell. The support plate 300 ensures that even if the insulating plastic part 100 melts and the electrode assembly moves towards the explosion-proof valve, the electrode assembly will not continue to move towards the explosion-proof valve due to the presence of the support plate 300, preventing the front end of the electrode assembly from blocking the explosion-proof valve. Furthermore, the ventilation gap 410 between the cover plate body 200 and the support plate 300 allows for venting, thereby improving the safety performance of the battery cell. The thermal runaway venting path of the battery cell in this application (in the early stage of thermal runaway, before the insulating plastic part 100 melts): battery cell interior - ventilation gap 410 / window 121 - explosion-proof valve, to meet the venting requirements.

[0034] Based on this, the support plate 300 passes through the opening 121, and the first insulating film 600 is flush with the side of the insulating plastic part 100 facing away from the cover plate body 200. This reduces the total height of the insulating plastic part 100 (its dimension in the thickness direction Z), reducing the occupied height space and increasing the cell capacity. In other words, the total height of the entire assembled cover plate (its dimension in the thickness direction Z) = the total height of the cover plate body 200 + the support protrusion 400 + the support plate 300 + the first insulating film 600. That is, the insulating plastic part 100 does not occupy extra space in the thickness direction Z (the length direction of the cell), thereby increasing the cell capacity. Figure 4As shown, the total height H2 (dimension in the thickness direction Z) of the entire assembled cover plate is equal to the total height H3 of the cover plate body 200 + supporting protrusion 400 + supporting plate 300 + first insulating film 600, where H3 = H2. The insulating plastic part 100 has the lowest height, ensuring the utilization rate of the cell space. In addition, after the electrode assembly is assembled with the cover plate, one end of the electrode assembly is attached to one side of the insulating plastic part 100 (including the first insulating film 600), ensuring the insulation performance at the contact point between the electrode assembly and the supporting plate 300.

[0035] In the embodiments of this application, preferably, the thickness t2 of the first insulating film 600 is 0.2mm-0.5mm, so as to balance the insulation performance at the contact position between the electrode group and the support plate 300 and the energy density of the entire cell.

[0036] Preferably, the first insulating film 600 includes an insulating film layer and an adhesive layer, and the first insulating film 600 is adhered to the support plate 300 by its own adhesive layer. The insulating film layer and the adhesive layer should meet the following conditions.

[0037] Insulating film layer: The material contains polypropylene (PP); its insulation resistance is greater than 1 gigaohm at 500VDC voltage; and its heat shrinkage rate is ≤4% after heat shrinkage for 8 hours at 120℃.

[0038] Adhesive layer: Uses thermally stable insulating adhesive; the adhesive layer is tested according to GB / T2792-2014 standard, with a 180° peel force greater than 30 Newtons (N); it is tested according to ASTM D3654 standard, with a holding force greater than 60 hours without peeling; and it is tested according to GB / T31125-2014 standard, with an initial tack greater than 20 Newtons (N).

[0039] In addition, in the embodiments of this application, in order to further enhance the exhaust effect, such as Figure 2 As shown, the support plate 300 has a vent 310 that penetrates through itself, and the first insulating film 600 has a through hole that penetrates through itself (the through hole is not shown in the figure). The positions of the through hole and the vent 310 correspond one-to-one.

[0040] In the embodiments of this application, preferably, such as Figure 1As shown, there are multiple support protrusions 400, which are arranged around the edge of the support plate 300. The dimensions of the support protrusions 400 in the thickness direction Z are between 2mm and 3mm. For example, there are four support protrusions 400, which are respectively located at the four corners of the support plate 300. The dimensions of the support protrusions 400 in the thickness direction Z are between 2mm and 3mm, meaning the distance between the support plate 300 and the cover plate body 200 is between 2mm and 3mm. With this arrangement, if the dimension of the support protrusion 400 in the thickness direction Z is less than 2mm, it will affect venting; if the dimension of the support protrusion 400 in the thickness direction Z is greater than 3mm, it will affect the energy density of the battery cell.

[0041] Preferably, the wall thickness of the support plate 300 in the thickness direction Z is t=0.8mm-1.5mm, so as to balance the support strength of the support plate 300 and the energy density of the overall battery cell.

[0042] In the embodiments of this application, such as Figures 3 to 6 As shown, the insulating plastic part 100 includes a first support portion 110, an exhaust portion 120, and a second support portion 130 connected sequentially along the length direction X. The first support portion 110 and the second support portion 130 have the same structure, and a window 121 is formed in the exhaust portion 120. In the thickness direction Z, the first support portion 110 and the second support portion 130 protrude from the side opposite to the cover plate body 200 relative to the exhaust portion 120, so as to form a height difference with the exhaust portion 120, so as to reserve space for the installation of the support protrusion 400, the support plate 300, and the first insulating film 600. Preferably, in the thickness direction Z, the support plate 300 passes through the opening 121, and the first insulating film 600 is flush with the side of the first support portion 110 and the second support portion 130 facing away from the cover plate body 200. The venting portion 120 is flush with the side of the first support portion 110 and the second support portion 130 facing the cover plate body 200. This arrangement can increase the contact area between the insulating plastic part 100 and the electrode group and the cover plate body 200 on both sides, thereby effectively ensuring the structural strength of the insulating plastic part 100 to meet the cell design requirements. That is, it ensures that the insulating plastic part 100 will not deform during the cell assembly process or during subsequent cell vibration, impact testing and use, thereby improving the safety performance of the cell.

[0043] Furthermore, in the embodiments of this application, in order to balance the venting effect and structural strength of the insulating plastic part 100, such as Figure 5 and Figure 6As shown, both the first support portion 110 and the second support portion 130 include a bottom wall 112 and an eave 113 surrounding the edge of the bottom wall 112. The first support portion 110 and the second support portion 130 form an exhaust groove 115 that opens to one side of the cover plate body 200. The bottom wall 112 has an exhaust hole 111 that penetrates through it. In the thickness direction Z, the side of the exhaust portion 120 facing the cover plate body 200 is flush with the eave 113. Both the eaves 113 of the first support portion 110 and the eaves 113 of the second support portion 130 have exhaust notches 114 on opposite sides in the length direction X. The side of the exhaust notch 114 facing the cover plate body 200 is open. The exhaust notch 114 connects the exhaust groove 115 and the window 121. The thermal runaway venting path of the battery cell in this application also includes (in the early stage of thermal runaway, before the insulating plastic part 100 melts): inside the battery cell - vent hole 111 - vent groove 115 - vent gap 114 - ventilation gap 410 / window 121 - explosion-proof valve 210, to meet the venting requirements.

[0044] Furthermore, to enhance the structural strength of the insulating plastic part 100, in the embodiments of this application, such as... Figure 6 As shown, a reinforcing rib 500 extending towards the cover plate body 200 is provided on the side of the bottom wall 112 facing the cover plate body 200. The reinforcing rib 500 is cross-shaped and connected to the edge 113 to divide the exhaust groove 115 into four small exhaust grooves. In addition, in the thickness direction Z, the reinforcing rib 500 should be lower than the edge 113 to facilitate communication between the four small exhaust grooves and to facilitate the exhaust of internal gas to the exhaust opening 114.

[0045] In the embodiments of this application, such as Figure 5 , Figure 6 and Figure 9 As shown, the two opposite ends of the window 121 in the length direction X extend to the edge 113 of the first support 110 and the second support 130 respectively, so as to balance the structural strength and ventilation effect of the insulating plastic part 100 and facilitate the installation of the support plate 300.

[0046] Preferably, such as Figure 8 and Figure 9 As shown, the cover plate satisfies the following conditions: 2mm ≤ (L2-L1) / 2 ≤ 4mm, 2mm ≤ (W2-W1) / 2 ≤ 4mm, where L2 is the dimension of the window 121 in the length direction X, L1 is the dimension of the support plate 300 in the width direction Y, W2 is the dimension of the window 121 in the width direction Y, and W1 is the dimension of the support plate 300 in the width direction Y. This setting, 2mm ≤ (L2-L1) / 2 and 2mm ≤ (W2-W1) / 2, ensures no interference during assembly; (L2-L1) / 2 ≤ 4mm and (W2-W1) / 2 ≤ 4mm, ensures the supporting effect of the support plate 300 and its own ventilation effect.

[0047] Preferably, such as Figure 9 As shown, the dimensions of the first support portion 110, the second support portion 130, and the exhaust portion 120 are equal in the width direction Y. The cover plate satisfies: 3mm ≤ (B-W2) / 2 ≤ 5mm, where B is the dimension of the insulating plastic part 100 in the width direction Y, and W2 is the dimension of the opening 121 in the width direction Y. With this configuration, if 3mm > (B-W2) / 2, the edge distance of the support portion is too small, the insulating plastic part 100 is prone to deformation, and the structural strength is insufficient. If (B-W2) / 2 > 5mm, it will affect the support effect of the support plate 300 and its own exhaust effect.

[0048] Preferably, such as Figure 9 As shown, the cover plate satisfies: 0.45 ≤ L2 / A ≤ 0.55, where A is the dimension of the insulating plastic part 100 in the length direction X, and L2 is the dimension of the window 121 in the length direction X. With this setting, if L2 / A > 0.55, the window 121 will be too long, the insulating plastic part 100 will be easily deformed, and the structural strength will be insufficient. If 0.45 > L2 / A, it will affect the supporting effect of the support plate 300 and its own ventilation effect.

[0049] Preferably, such as Figure 7 As shown, the wall thickness h of the exhaust section 120 in the thickness direction Z is 1mm-1.5mm, in order to balance the structural strength of the insulating plastic part 100 and the energy density of the battery cell.

[0050] To verify the above scheme, different experimental designs were designed, and the results are as follows:

[0051] It is evident that when the above design scheme is met, the strength of the cover plate structure and the venting meet the requirements. At the same time, the battery cell structure can effectively avoid the problem of the upper electrode group moving and blocking the explosion-proof valve 210, which affects the venting effect of the explosion-proof valve 210, and greatly improves the safety performance of the battery cell.

[0052] According to a second aspect of this application, a battery cell is provided, including a cover plate as described above. The battery cell further includes an electrode assembly and a second insulating film. The electrode assembly includes an outer surface and an end face in the thickness direction. The end face of the electrode assembly is in contact with a first support portion 110, a second support portion 130, and a first insulating film 600. The second insulating film covers the outer surface of the electrode assembly (here, the outer surface refers to all outer surfaces except the end face of the electrode assembly). One end of the second insulating film in the thickness direction is open, and the other end of the second insulating film in the thickness direction is fixedly connected to an edge 113.

[0053] With this configuration, after the second insulating film wraps around the electrode assembly, one end is heat-fused to the edge 113 of the insulating plastic part. Moreover, when the electrode assembly is assembled with the cover plate, the end face of the electrode assembly is in contact with one side of the insulating plastic part (including the first insulating film 600), which can ensure the insulation performance of the contact position between the electrode assembly and the support plate.

[0054] Finally, it should be noted that the above-described embodiments are merely specific implementations of this application, used to illustrate the technical solutions of this application, and not to limit them. The protection scope of this application is not limited thereto. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments within the scope of the technology disclosed in this application, or make equivalent substitutions for some of the technical features. Such modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be covered within the protection scope of this application.

Claims

1. A cover plate, characterized in that, The cover plate has a thickness direction, and the cover plate includes an insulating plastic part, a cover plate body, a support plate and a first insulating film. The insulating plastic part is disposed on one side of the cover plate body in the thickness direction, and the cover plate body is provided with an explosion-proof valve. The cover plate body has a support protrusion on the side facing the insulating plastic part, which protrudes toward the side where the insulating plastic part is located. The support plate is connected to the support protrusion to form an air gap with the cover plate body. The insulating plastic part is attached to the cover plate body on one side in the thickness direction, and the other side is used to attach to the electrode assembly; along the thickness direction, the insulating plastic part is provided with a through-hole, the support plate passes through the through-hole, the first insulating film is attached to the support plate and is flush with the side of the insulating plastic part that is opposite to the cover plate body; the support plate, the explosion-proof valve and the through-hole are arranged facing each other in the thickness direction.

2. The cover plate according to claim 1, characterized in that, The thickness t2 of the first insulating film is 0.2mm-0.5mm. The first insulating film includes an insulating film layer and an adhesive layer. The first insulating film is adhered to the support plate by its own adhesive layer. And / or, the support plate has a vent hole that penetrates through it, and the first insulating film has a through hole that penetrates through it, with the through hole and the vent hole being positioned one-to-one.

3. The cover plate according to claim 2, characterized in that, The cover plate also has a length direction perpendicular to the thickness direction. The insulating plastic part includes a first support part, an exhaust part and a second support part connected sequentially along the length direction. The first support part and the second support part have the same structure. The window is opened in the exhaust part. In the thickness direction, the first support portion and the second support portion protrude relative to the exhaust portion toward the side opposite to the cover plate body, and the first insulating film is flush with the side of the first support portion and the second support portion opposite to the cover plate body. In the thickness direction, the vent is flush with one side of the first support and the second support facing the cover body.

4. The cover plate according to claim 3, characterized in that, Both the first support portion and the second support portion include a bottom wall and an edge provided around the edge of the bottom wall. The first support portion and the second support portion form an exhaust groove that opens to one side of the cover plate body. The bottom wall has an exhaust hole that penetrates itself. In the thickness direction, the side of the vent facing the cover plate body is flush with the edge. The edge of the first support and the edge of the second support are both provided with venting notches on opposite sides in the length direction. The side of the venting notch facing the cover plate body is open. The venting notch connects the venting groove and the window.

5. The cover plate according to claim 4, characterized in that, The window extends to the eaves of the first support and the second support at opposite ends along the length direction, respectively. And / or, a reinforcing rib extending toward the side of the cover plate body is provided on the side of the bottom wall facing the cover plate body, and the reinforcing rib is lower than the edge in the thickness direction.

6. The cover plate according to claim 4, characterized in that, The cover plate also has a width direction, and the length direction, the width direction and the thickness direction are perpendicular to each other; The dimensions of the first support, the second support, and the exhaust portion are equal in the width direction, and the cover plate satisfies: 3mm≤(B-W2) / 2≤5mm, where B is the dimension of the insulating plastic part in the width direction, and W2 is the dimension of the window in the width direction.

7. The cover plate according to claim 4, characterized in that, The cover plate also has a width direction, and the length direction, the width direction and the thickness direction are perpendicular to each other; The dimensions of the first support, the second support, and the exhaust portion are equal in the width direction, and the cover plate satisfies: 0.45≤L2 / A≤0.55, where A is the dimension of the insulating plastic part in the length direction, and L2 is the dimension of the window in the length direction.

8. The cover plate according to claim 4, characterized in that, The cover plate also has a width direction, and the length direction, the width direction and the thickness direction are perpendicular to each other; The cover plate satisfies: 2mm≤(L2-L1) / 2≤4mm, 2mm≤(W2-W1) / 2≤4mm, where L2 is the dimension of the opening in the length direction, L1 is the dimension of the support plate in the width direction, W2 is the dimension of the opening in the width direction, and W1 is the dimension of the support plate in the width direction.

9. The cover plate according to claim 4, characterized in that, The number of the support protrusions is multiple, and the multiple support protrusions are arranged around the edge of the support plate. The size of the support protrusions in the thickness direction is between 2mm and 3mm. The wall thickness of the support plate in the thickness direction is t=0.8mm-1.5mm, and the wall thickness of the exhaust part in the thickness direction is h=1mm-1.5mm.

10. A battery cell, characterized in that, The battery cell includes the cover plate according to any one of claims 4-9, and further includes an electrode assembly and a second insulating film; The electrode assembly includes an outer surface and an end face in the thickness direction. The end face of the electrode assembly is in contact with the first support portion, the second support portion, and the first insulating film. The second insulating film covers the outer surface of the electrode assembly. One end of the second insulating film in the thickness direction is open and fixedly connected to the edge in the thickness direction.

Images