A battery cell

Abstract

The utility model provides a kind of battery monomer, comprising: shell, the shell has opening;Cover plate, the cover plate is used to cover and close the opening, the cover plate includes the top surface away from the inside of the shell, the top surface has the recessed area recessed towards the inside of the shell;First insulating piece, the first insulating piece is fixed on the top surface and covers the recessed area, the first insulating piece has pressure relief structure, the pressure relief structure is configured to make the pressure in the recessed area not more than threshold value, pressure relief structure guarantees the insulating property of first insulating piece, ensure the use safety and reliability of battery monomer.

Description

Technical Field

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

[0002] In the development of battery technology, besides improving the performance of individual battery cells, safety is also a crucial issue that cannot be ignored. If the safety of individual battery cells cannot be guaranteed, then those cells cannot be used. Therefore, how to enhance the safety of individual battery cells is a pressing technical problem that needs to be solved in battery technology. Utility Model Content

[0003] This utility model provides a battery cell to solve the technical problem that the insulating components covered by the battery cell cover plate are damaged or fail to connect due to changes in air pressure in the recessed area on the top surface of the cover plate.

[0004] The battery cell provided by this utility model includes: a housing having an opening; a cover plate for closing the opening, the cover plate including a top surface away from the interior of the housing, the top surface having a recessed area facing the interior of the housing; and a first insulating member fixed to the top surface and covering the recessed area, the first insulating member having a pressure relief structure configured such that the pressure in the recessed area does not exceed a threshold value.

[0005] In one embodiment of the present invention, the pressure relief structure is an exhaust hole, which penetrates the first insulating member along the thickness direction of the first insulating member; along the thickness direction of the cover plate, the orthographic projection of the exhaust hole on the top surface of the cover plate is at least partially located within the recessed area.

[0006] In one embodiment of this utility model, the pressure relief structure is a thinning portion, the first insulating member and the recessed area form a closed chamber, the thinning portion defines a pressure relief area, and the thinning portion is configured to open with the thinning portion as the boundary when the pressure in the recessed area reaches a threshold, so as to release the pressure in the recessed area; along the thickness direction of the first insulating member, the maximum thickness of the thinning portion is less than the maximum thickness of the first insulating member; along the thickness direction of the cover plate, the orthographic projection of the thinning portion on the top surface of the cover plate is at least partially located in the recessed area.

[0007] In one embodiment of the present invention, along the thickness direction of the first insulating member, the maximum thickness of the thinned portion is H1, the maximum thickness of the first insulating member is H2, and H1 / H2≤0.8.

[0008] In one embodiment of this utility model, the pressure relief structure is an exhaust port, which connects the recessed area to the outside. Along the thickness direction of the cover plate, the orthographic projection of the exhaust port on the cover plate is located outside the recessed area. Along the thickness direction of the cover plate, the cover plate includes a bottom surface opposite to the top surface, and the first insulating member includes a first surface away from the interior of the housing. The battery cell also includes an exhaust channel, which is disposed between the first surface and the bottom surface, and the exhaust port communicates with the recessed area through the exhaust channel.

[0009] Furthermore, in one embodiment of the present invention, the exhaust channel is formed by the top surface being recessed towards the bottom surface; and / or the first insulating member includes a second surface disposed opposite to the first surface along the thickness direction, and the exhaust channel is formed by the second surface being recessed towards the first surface.

[0010] Furthermore, in one embodiment of the present invention, the first insulating member further includes a marking portion, which is used to form a pattern to distinguish the positive and negative electrodes of the battery cell, and the marking portion is the vent hole; or the marking portion is a vent outlet, and the vent outlet penetrates the first insulating member along the thickness direction of the first insulating member.

[0011] Furthermore, in one embodiment of the present invention, the exhaust port is disposed on at least one side of the first insulating member along a preset direction, the preset direction being perpendicular to the thickness direction of the first insulating member; the first insulating member includes a second surface disposed opposite to the first surface along the thickness direction, and the exhaust port is formed by the second surface being recessed into the first surface.

[0012] Furthermore, in one embodiment of the present invention, the battery cell further includes a second insulating member, which is laid on the outer surface of the housing. The second insulating member includes a flanged portion located between the first insulating member and the cover plate, and the flanged portion is fixedly connected to the first insulating member. Along the preset direction, the minimum dimension of the flanged portion is L, where L≥5mm.

[0013] Furthermore, in one embodiment of the present invention, along the length direction of the cover plate, the minimum distance between the recessed area and the edge of the cover plate is D1, the maximum size of the cover plate is D2, and D1 / D2≥1 / 3.

[0014] Compared with the prior art, the present invention has at least the following beneficial effects:

[0015] This invention features a pressure relief structure on the first insulating component. When the battery cell generates heat during operation, causing the gas in the enclosed space to expand and the pressure to rise, the pressure relief structure can promptly release the high-pressure gas, preventing pressure buildup and avoiding situations where the first insulating component bulges, tears, or even fails to adhere to the cover plate due to excessive pressure. This prevents dangerous situations such as short circuits and leakage caused by damage to the first insulation. Furthermore, the pressure relief structure on the first insulating component adds almost no additional material costs or manufacturing process complexity, making it highly suitable for application in mass production. Attached Figure Description

[0016] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. It is obvious that the drawings described below are merely some embodiments of this application, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0017] In the attached diagram:

[0018] Figure 1 A schematic diagram showing the unfolded components of a battery cell according to an embodiment of the present invention;

[0019] Figure 2 This is a front view of the first insulating member, which is provided as an exhaust port in one embodiment of the present invention for relieving pressure.

[0020] Figure 3 This is a front view of the first insulating member, which is provided as an exhaust port in a certain embodiment of the present utility model;

[0021] Figure 4 This is a front view of the first insulating member, which is a thinned portion, provided in one embodiment of the present invention for relieving pressure.

[0022] Figure 5 yes Figure 4 Sectional view along the AA direction;

[0023] Figure 6 yes Figure 5 A magnified view of a portion of Part B;

[0024] Figure 7 This is a front view of the first insulating member, which is a thinned portion, provided in a certain embodiment of the present invention for relieving pressure.

[0025] Figure 8 yes Figure 7 Sectional view in the CC direction;

[0026] Figure 9This is a front view of the first insulating member, which is a thinned portion, provided in one embodiment of the present utility model as a pressure relief structure;

[0027] Figure 10 yes Figure 9 Sectional view in the DD direction;

[0028] Figure 11 This is a front view of the first insulating member, which is a thinned portion, provided in another embodiment of the present invention for relieving pressure.

[0029] Figure 12 This is a front view of a first insulating member provided in one embodiment of the present invention, where the pressure relief structure is an exhaust port and the first insulating member has an exhaust channel;

[0030] Figure 13 yes Figure 7 Sectional view in the EE direction;

[0031] Figure 14 This is a front view of a first insulating member provided in one embodiment of the present invention, wherein the marking part is an exhaust port and the first insulating member has an exhaust channel;

[0032] Figure 15 This is a front view of the first insulating member with an exhaust hole as the marking part provided in one embodiment of the present invention;

[0033] Figure 16 This is a front view of a first insulating member provided in one embodiment of the present invention, wherein the exhaust port is disposed along one side of the first insulating member along a preset direction and the first insulating member has an exhaust channel.

[0034] Figure 17 This is a schematic diagram showing the unfolded components of a battery cell including a second insulating member, provided in one embodiment of the present invention.

[0035] Figure 18 This is a schematic diagram of the structure of the cover plate provided in one embodiment of the present invention.

[0036] The attached figures are labeled as follows:

[0037] 100, Cover plate; 110, Recessed area; 200, First insulating component; 210, Pressure relief structure; 211, Vent hole; 212, Thinning section; 213, Vent outlet; 214, Marking section; 220, First surface; 230, Second surface; 300, Vent passage; 400, Housing; 500, Second insulating component; 510, Flanged edge; 600, Explosion-proof valve; 700, Pole post. Detailed Implementation

[0038] The following specific examples illustrate the implementation of this utility model. Those skilled in the art can easily understand other advantages and effects of this utility model from the content disclosed in this specification. This utility model can also be implemented or applied through other different specific embodiments. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this utility model. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0039] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. The drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components. In actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0040] To improve the insulation performance of battery cells, an insulating layer is typically placed on the cover of the battery cell. The top surface where the cover and the insulating layer meet often has a recessed area for other functional requirements, creating a relatively enclosed space between the insulating layer and the recessed area. In some cases, the battery cell generates heat during use, some of which is transferred to the cover, raising its temperature. This increased temperature causes the gas between the insulating layer and the recessed area to expand, increasing the pressure within the enclosed space. Since the cover is typically stronger than the insulating layer, the insulating layer is more susceptible to pressure changes, leading to bulging or deformation. In more severe cases, the insulating layer may even be lifted or broken, causing the connection between it and the cover to fail, thus reducing the insulation performance of the battery cell and compromising its safety and reliability. This invention addresses this by incorporating a pressure relief structure on the insulating layer to ensure that the pressure in the recessed area does not exceed a threshold, thereby maintaining a certain degree of integrity of the insulating layer and the connection strength between it and the cover.

[0041] The technical solution of this utility model will be described in detail below with reference to specific embodiments:

[0042] Please see Figures 1-18The battery cell provided by this utility model includes: a housing 400, a cover plate 100, and a first insulating member 200. The housing 400 has an opening for easy installation of electrode components. The cover plate 100 is used to close the opening. The cover plate 100 includes a top surface away from the interior of the housing 400. The top surface of the cover plate 100 has a recessed area 110 that is recessed toward the interior of the housing 400. The first insulating member 200 is fixed to the top surface and covers the recessed area 110. The first insulating member 200 has a pressure relief structure 210. Specifically, the pressure relief structure 210 can be a vent 211, a thinning portion 212, etc. The pressure relief structure 210 can ensure that the pressure in the recessed area 110 does not exceed a threshold.

[0043] The pressure relief structure 210 provides a pressure release channel for the closed space formed between the first insulating component 200 and the recessed area 110 of the cover plate 100. When the battery cell heats up during operation, causing the gas in the closed space to expand and the pressure to rise, the pressure relief structure 210 can release the high-pressure gas in time, avoiding pressure accumulation and preventing the first insulating component 200 from bulging, tearing, or being pushed up due to excessive pressure, resulting in failure of connection with the cover plate 100 or even detachment. This prevents dangerous situations such as short circuits, leakage, and end cover corrosion caused by damage to the first insulating component 200. In addition, setting the pressure relief structure 210 on the first insulating component 200 adds almost no additional material cost or manufacturing process complexity, so it is also very conducive to application in mass production.

[0044] Please see Figure 2 , Figure 3 , Figure 15 In an optional embodiment of this utility model, the pressure relief structure 210 is an exhaust hole 211, which penetrates the first insulating member 200 along its thickness direction. Along the thickness direction of the cover plate 100, the orthographic projection of the exhaust hole 211 on the top surface of the cover plate 100 is at least partially located within the recessed area 110. That is, the exhaust hole 211 can be a through hole located directly above the recessed area 110, with an opening area equal to or smaller than the area of ​​the recessed area 110. Alternatively, it can be a through hole entirely located obliquely above the recessed area 110, but with a portion of its orthographic projection located within the recessed area 110. Specifically, the shape of the exhaust hole 211 can be... Figure 2 The rectangle shown can also be Figure 3 The circle shown can also be an ellipse, a cross, or a combination of shapes. The cross-sectional area of ​​the vent 211 cannot be too large. An excessively large vent 211 can cause external foreign objects to fall into the recessed area 110 and come into contact with the cover plate 100, easily trapping metal shavings, foreign objects, particles, and other impurities, potentially causing short circuits and cover plate corrosion. In some embodiments, the maximum cross-sectional area of ​​a single vent 211 does not exceed 15 mm². 2 It can be 1mm 2 2mm2 2.5mm 2 4mm 2 5mm 2 9mm 2 12mm 2 For example, a single vent 211 can be a round hole with a diameter of 4 mm or a square hole with a side length of 2 mm, without any specific limitation here.

[0045] Vent 211 is normally open, so even small changes in pressure inside the recessed area 110 will be responded to promptly by vent 211, allowing the internal pressure of the recessed area 110 to balance with the external pressure, thereby reducing the risk of failure of the first insulating component 200. Therefore, the pressure relief structure 210 is configured to ensure that the pressure inside the recessed area 110 does not exceed a threshold value; in other words, due to the presence of the pressure relief structure 210, the pressure inside the recessed area 110 does not exceed a certain value. This threshold value may differ for different battery cells in different embodiments. For example, in some embodiments where vent 211 is provided, this threshold value is approximately the external pressure of the battery cell. It should be noted that for the same battery cell, this threshold value can also vary. For example, when the external pressure changes, the threshold value in some embodiments will also change accordingly. The presence of the pressure relief structure 210 ensures that the difference between the pressure inside the recessed area and this threshold value is always within a certain range and does not exceed the threshold value. That is, this threshold value can be adjusted by adjusting the size of the recessed area 110, the size of the first insulating component 200, the setting method of the pressure relief mechanism 210, or the external pressure. In addition, the temperature of some battery cells may rise and fall repeatedly during use. As a result, the pressure in the recessed area 110 will also fluctuate. At this time, the first insulator 200 will be affected by cyclic stress, which may cause the connection between the first insulator 200 and the cover plate 100 to fail. However, the vent 211 can respond to the cyclic changes of pressure for a long time, thereby maintaining the insulation performance of the first insulator 200 during long-term use.

[0046] Please see Figures 4-11 In an optional embodiment of this utility model, the pressure relief structure 210 is a thinning portion 212. The first insulating member 200 and the recessed area 110 form a closed chamber. The thinning portion 212 defines a pressure relief area. The thinning portion 212 is configured to open with the thinning portion 212 as the boundary when the pressure in the recessed area 110 reaches a threshold, so as to release the pressure in the recessed area 110. Along the thickness direction of the first insulating member 200, the maximum thickness of the thinning portion 212 is less than the maximum thickness of the first insulating member 200. Along the thickness direction of the cover plate 100, the orthographic projection of the thinning portion 212 on the top surface of the cover plate 100 is at least partially located within the recessed area 110. Specifically, the thinning portion 212 can be as shown in Figure 4- Figure 6The rectangular groove shown can also be a groove of other shapes, or a closed annular groove, or a partially annular groove. In some embodiments, the thinning portion 212 can be as follows: Figures 4-6 As shown in the narrow, elongated region, when the pressure within the recessed region 110 reaches a threshold, the narrow, elongated thinning portion 212 can rupture and open to form a narrow slit, reducing the strength of the first insulating member 200 in the vicinity. The gas within the recessed region 110 causes a partial height difference in the thickness direction between the first insulating members 200 on both sides of the slit, allowing some pressure to escape through the space created by this height difference. In other embodiments, the thinning portion 212 can be as follows: Figures 7-8 The thinning region shown has a certain area, and its outline can be rectangular, parallelogram, circular, or polygonal. Within this thinning region, the thinned portions 212 have essentially the same thickness, and the maximum thickness within the thinning region is less than the maximum thickness of the first insulating member 200. When the pressure within the recessed region 110 reaches a threshold, the first insulating member 200 can open along the boundary between the thinned region and the non-thinned region, and can also open at a partial location within the thinned region. This helps reduce processing difficulty and improves pressure relief efficiency and reliability. In some other embodiments, the thinned portion 212 can be a combination of one or more thinning segments, and these thinning segments can be made using, for example... Figures 9-10 The figure shown can be formed by connecting the beginning and end of a circle to create a closed figure. Alternatively, it can be represented as follows: Figure 11 The non-closed shape shown is not specifically limited here. When the pressure inside the recessed area 110 reaches the threshold, the first insulating member 200 can be opened along the closed thinning section, causing the portion of the first insulating member 200 surrounded by the closed thinning section to fall off, releasing the pressure inside the recessed area 110, or it can be broken open along the non-closed thinning section, causing part of the first insulating member 200 to flip along the unbroken part, connecting the recessed area 110 with the outside, releasing the pressure inside the recessed area 110.

[0047] Specifically, the first insulating member 200 can be a composite structure made of insulating and flame-retardant polycarbonate (PC) or similar substrate with adhesive backing. The adhesive backing is used to attach the first insulating member 200 to the top surface of the cover plate 100. In this case, a thinning portion 212 can be formed by not providing adhesive backing directly below a portion of the first insulating member 200. In other embodiments, the thinning portion 212 can be formed by further thinning on the substrate. To prevent the thinning portion 212 from being too thick, resulting in a high structural strength at the thinning portion 212 and causing the pressure change in the recessed area 110 to be unable to open the thinning portion 212, the ratio of the maximum thickness of the thinning portion 212 to the maximum thickness of the first insulating member 200 can be limited to a range not exceeding 0.8. For example, this ratio can be 0.2, 0.3, 0.4, 0.45, 0.55, 0.7, or 0.8. Furthermore, when the thickness of the thinned portion 212 is too small, it is not convenient to manufacture and form the first insulating member 200, and the reliability of the thinned portion 212 is reduced. It is easy for it to open on its own due to external impact or vibration when the pressure in the recessed area 110 has not reached the threshold, thereby reducing the insulation effect of the first insulating member 200 on the cover plate 100. Therefore, the aforementioned ratio can be no less than 0.2 and no more than 0.8 to ensure that the first insulating member 200 can always open at the preset thinned portion 212, thereby improving reliability.

[0048] In some battery cells, an explosion-proof valve 600 is provided on the cover plate 100 to open and release the internal pressure of the housing 400 when the pressure inside the housing 400 reaches a threshold. The explosion-proof valve 600 can be located near the center of the cover plate 100 or near one edge of the cover plate 100. The working principle of the thinning part 212 in the above design is similar to that of some explosion-proof valves 600; both of them rupture and open to release pressure after being subjected to a certain pressure. Since the thinning portion 212 is thinned based on the thickness of the first insulating member 200, when the pressure in the recessed area does not exceed the threshold (as in normal conditions), the thinning portion 212 is connected to the other parts of the first insulating member 200. That is to say, the surface of the first insulating member 200 on the side away from the cover plate 100 is intact, and there is no situation where part of the cover plate 100 is exposed to the outside due to the opening of the thinning portion 212. This is beneficial to maintain the integrity of the first insulating member 200, reduce the probability of foreign objects entering the recessed area 110 through the first insulating member 200 and causing short circuits or damage to the cover plate 100, and improve the environmental adaptability and long-term reliability of the battery cell. During battery use, when the air pressure in the recessed area 110 is abnormal due to heat, vibration or impact, the first insulating member 200 is opened with the thinning portion 212 as the boundary to achieve directional and reliable pressure relief.

[0049] Please see Figure 6In an optional embodiment of this utility model, along the thickness direction of the first insulating member 200, the maximum thickness of the thinned portion 212 is H1, and the maximum thickness of the first insulating member 200 is H2. The ratio of H1 to H2 is less than or equal to 0.8, to ensure that the thinned portion 212 and other parts of the first insulating member 200 have a significant thickness difference, so that the mechanical strength of the thinned portion 212 is significantly lower than that of other parts of the first insulating member 200. This ensures that when the air pressure in the recessed area 110 increases, the first insulating member 200 will inevitably be torn open in a timely and sensitive manner with the thinned portion 212 as the boundary, rather than randomly opening from an uncertain point on the first insulating member 200. In addition, in order to prevent the thinned portion 212 from being too thin to be difficult to form or from being accidentally damaged by a little external pressure, causing debris to enter the recessed area 110 and causing problems such as short circuit or corrosion of the cover plate 100, in some embodiments, the ratio of H1 to H2 can be further made to satisfy a value greater than or equal to 0.5 and less than or equal to 0.8.

[0050] Please see Figures 12-14 , Figure 16 In an optional embodiment of this utility model, the pressure relief structure 210 is an exhaust port 213. The exhaust port 213 connects the recessed area 110 and the outside. Along the thickness direction of the cover plate 100, the orthographic projection of the exhaust port 213 on the cover plate 100 is located outside the recessed area 110, that is, the exhaust port 213 and the recessed area 110 are staggered in a plane perpendicular to the thickness direction of the cover plate 100. Along the thickness direction of the cover plate 100, the cover plate 100 includes a bottom surface opposite to the top surface. The first insulating member 200 includes a first surface 220 away from the interior of the housing 400. The battery cell also includes an exhaust channel 300. The exhaust channel 300 is disposed between the first surface 220 and the bottom surface. The exhaust port 213 is connected to the recessed area 110 through the exhaust channel 300. Specifically, the exhaust port 213 can be a through hole opened on the first insulating member 200 or a groove provided on the edge of the first insulating member 200.

[0051] In the above structural design, the exhaust port 213 is not located directly above the recessed area 110. The recessed area 110 has a greater depth than the non-recessed area of ​​the cover plate 100, posing a greater risk of accumulating foreign objects and increasing the probability of short circuits or corrosion. Therefore, by offsetting the exhaust port 213 from the recessed area 110 compared to placing it directly above it, the risk of foreign objects accumulating between the cover plate 100 and the first insulating member 200 can be minimized. On one hand, this design significantly reduces the probability of external foreign objects entering the recessed area 110 through the exhaust port 213. On the other hand, the exhaust port 213 can be flexibly positioned to avoid the main coverage area of ​​the first insulating member 200, thereby better ensuring the insulation performance of the first insulating member 200. Simultaneously, the exhaust channel 300 can guide the high-pressure gas in the recessed area 110 to the exhaust port 213 for timely discharge, achieving a reliable pressure relief function.

[0052] In an optional embodiment of this utility model, the exhaust channel 300 is formed by a recess from the top surface of the cover plate 100 toward the bottom surface. Specifically, the groove for forming the exhaust channel 300 can be stamped, cut, or etched on the top surface of the cover plate 100. Since the cover plate 100 is generally made of copper or aluminum, the exhaust channel 300 has high structural strength. In addition, it can also keep the first insulating member 200 relatively intact; and / or as Figures 7-9 , Figure 11 As shown, the first insulating member 200 includes a second surface 230 disposed opposite to the first surface 220 along the thickness direction. An exhaust channel 300 is formed by recessing from the second surface 230 toward the first surface 220. Specifically, the groove-shaped exhaust channel 300 can be machined into the first insulating member 200 by means of molding, hot cutting, machining, or integral molding. Alternatively, the first insulating member 200 can adopt a structure with an insulating and flame-retardant material such as polycarbonate (PC) as the base material and adhesive backing. In this case, it can be achieved by leaving certain areas un-adhesive. An adhesive backing is used to form the venting channel 300. Specifically, the thickness of the adhesive layer can be between 0.05mm and 0.2mm. Furthermore, to prevent the venting channel 300 from being too narrow to function properly, and too wide to cause the first insulating component 200 to fail, and to prevent the hiding of foreign objects, the width of the un-adhesive area used to form the venting channel 300 can be between 0.5mm and 5mm. In addition, at least one venting channel 300 should pass through or communicate with the recessed area 110. In some embodiments, the number of venting channels 300 does not exceed four. Specifically, when the venting channel 300 is straight, each segment can be considered as one channel (e.g., ...). Figure 12(A channel running longitudinally or laterally). When the exhaust channel 300 is curved, each segment of the curve can be considered a channel. The structure connecting the exhaust channel 300 and the exhaust port 213 is not included in the number of exhaust channels. The design of this embodiment helps to avoid the situation where the connection area between the first insulating member 200 and the cover plate 100 is too small due to an excessive number of exhaust channels 300, which would cause the first insulating member 200 to easily separate from the cover plate 100 and fail, thereby reducing the insulation performance of the cover plate 100 and reducing the creepage distance.

[0053] The above design hides the exhaust channel 300 between the top surface of the cover plate 100 and the first surface 220 of the first insulating member 200, without taking up extra space, and can reliably realize the function of the auxiliary exhaust port 213 for pressure relief.

[0054] Please see Figure 15 In an optional embodiment of this utility model, the first insulating member 200 further includes a marking portion 214, which is used to form a pattern to distinguish the positive and negative electrodes of the battery cell. The marking portion 214 is a vent hole 211; or please refer to Figure 9 The marking portion 214 serves as the exhaust port 213, which penetrates the first insulating member 200 along its thickness direction. In some embodiments, the marking portions 214 for the positive and negative electrodes are generally located on the side of the corresponding polarity pole 700, while the pole 700 is located closer to both ends of the cover plate 100 along its length. The explosion-proof valve 600 is installed in the middle of the cover plate 100 along its length. The recessed area 110 is typically formed by stamping a bulge towards the internal electrode assembly of the housing 400 around the explosion-proof valve 600. In this way, the high-pressure gas in the recessed area 110 in the middle can be guided to the marking portion 214 through the exhaust channel 300 and then discharged. Compared with the scheme of setting the exhaust port 213 on the edge of the first insulating member 200 without setting the backing adhesive, the first insulating member 200 in the above scheme does not reduce the backing adhesive area at the edge and can be more firmly bonded to the cover plate 100.

[0055] The above design integrates the pressure relief function and the marking function into the marking part 214, thereby realizing the multi-functionality of the parts. This not only simplifies the structure and reduces costs, but also optimizes the spatial layout and avoids the possibility of mutual interference between functional components.

[0056] Please see Figure 16In an optional embodiment of the present invention, the exhaust port 213 is disposed on at least one side of the first insulating member 200 along a preset direction, the preset direction being perpendicular to the thickness direction of the first insulating member 200, that is, the exhaust port 213 is disposed at the edge of the first insulating member 200; the first insulating member 200 includes a second surface 230 disposed opposite to the first surface 220 along the thickness direction, and the exhaust port 213 is formed by recessing from the second surface 230 toward the first surface 220. This structural design, while realizing the pressure relief function, ensures the integrity of the first insulating member 200 as much as possible, thereby ensuring its insulation performance.

[0057] Please see Figure 17 In an optional embodiment of this utility model, the battery cell further includes a second insulating member 500. The second insulating member 500 is applied to the outer surface of the housing 400. Specifically, the second insulating member 500 may be a blue film. The second insulating member 500 includes a flanged portion 510 located between the first insulating member 200 and the cover plate 100. The flanged portion 510 extends from the edge of the cover plate 100 toward the center area of ​​the cover plate 100. The flanged portion 510 is fixedly connected to the first insulating member 200. Along a preset direction, the minimum dimension of the flanged portion 510 is L, where L≥5mm.

[0058] When the vent 213 is located at the edge of the first insulating member 200, in order to connect the recessed area 110 and the vent 213, the first insulating member 200 near the vent 213 will also have a venting channel 300 formed by the second surface 230 recessing towards the first surface 220. Especially when the venting channel 300 is formed without adhesive backing, the connection area between the edge and the flange 510 of the first insulating member 200 may be reduced, thereby reducing the connection strength between them. This may result in the edge of the first insulating member 200 lifting up, which is not conducive to improving the insulation performance of the battery cell. Therefore, by ensuring the minimum size of the flange 510 of the second insulating member 500, the insulation safety of the edge area of ​​the cover plate 100 is guaranteed.

[0059] Please see Figure 18 In an optional embodiment of this utility model, along the length direction of the cover plate 100, the minimum distance between the recessed area 110 and the edge of the cover plate 100 is D1, and the maximum size of the cover plate 100 is D2, where D1 / D2≥1 / 3. That is, the recessed area 110 is set in the middle area of ​​the cover plate 100 as much as possible, rather than at the end. This allows the flanged part 510 to be more firmly bonded to the top surface of the cover plate 100, thereby avoiding the situation where the flanged part 510 lifts up later, causing the edge of the first insulating member 200 to pop up. This ensures the insulation effect of the first insulating member 200 on the cover plate 100 and improves the safety of the battery cell.

[0060] The above embodiments are merely illustrative of the principles and effects of this utility model and are not intended to limit the scope of this utility model. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of this utility model. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this utility model should still be covered by the claims of this utility model.

Claims

1. A battery cell, characterized in that, include: A housing having an opening; A cover plate for closing the opening, the cover plate including a top surface away from the interior of the housing, the top surface having a recessed area recessed toward the interior of the housing; A first insulating element is fixed to the top surface and covers the recessed area. The first insulating element has a pressure relief structure configured to ensure that the pressure in the recessed area does not exceed a threshold value.

2. The battery cell according to claim 1, characterized in that, The pressure relief structure is an exhaust port, which penetrates the first insulating member along the thickness direction of the first insulating member; Along the thickness direction of the cover plate, the orthographic projection of the vent hole on the top surface of the cover plate is at least partially located within the recessed area.

3. The battery cell according to claim 1, characterized in that, The pressure relief structure is a thinning section. The first insulating member and the recessed area form a closed chamber. The thinning section defines a pressure relief area. The thinning section is configured to open with the thinning section as the boundary when the pressure in the recessed area reaches a threshold, so as to release the pressure in the recessed area. Along the thickness direction of the first insulating member, the maximum thickness of the thinned portion is less than the maximum thickness of the first insulating member; Along the thickness direction of the cover plate, the orthographic projection of the thinned portion on the top surface of the cover plate is at least partially located within the recessed area.

4. The battery cell according to claim 3, characterized in that, The maximum thickness of the thinned portion is H1, and the maximum thickness of the first insulating component is H2, where H1 / H2 ≤ 0.

8.

5. The battery cell according to claim 1, characterized in that, The pressure relief structure is an exhaust port, which connects the recessed area to the outside. Along the thickness direction of the cover plate, the orthographic projection of the exhaust port on the cover plate is located outside the recessed area. Along the thickness direction of the cover plate, the cover plate includes a bottom surface disposed opposite to the top surface, and the first insulating member includes a first surface away from the interior of the housing; The battery cell also includes an exhaust channel, which is disposed between the first surface and the bottom surface, and the exhaust port communicates with the recessed area through the exhaust channel.

6. The battery cell according to claim 5, characterized in that, The exhaust channel is formed by a recess from the top surface toward the bottom surface; and / or The first insulating member includes a second surface disposed opposite to the first surface along the thickness direction, and the exhaust channel is formed by the second surface being recessed into the first surface.

7. The battery cell according to claim 2, characterized in that, The first insulating member further includes a marking portion, which is used to form a pattern distinguishing the positive and negative electrodes of the battery cell, and the marking portion is the vent hole; or The marking part is an exhaust port, which penetrates the first insulating member along the thickness direction of the first insulating member.

8. The battery cell according to claim 5, characterized in that, The exhaust port is disposed on at least one side of the first insulating member along a preset direction, the preset direction being perpendicular to the thickness direction of the first insulating member; The first insulating member includes a second surface disposed opposite to the first surface along the thickness direction, and the exhaust port is formed by the second surface being recessed into the first surface.

9. The battery cell according to claim 8, characterized in that, It also includes a second insulating element, which is laid on the outer surface of the housing. The second insulating element includes a flanged portion located between the first insulating element and the cover plate, and the flanged portion is fixedly connected to the first insulating element. Along the preset direction, the minimum dimension of the flange is L, where L ≥ 5 mm.

10. The battery cell according to claim 9, characterized in that, Along the length of the cover plate, the minimum distance between the recessed area and the edge of the cover plate is D1, the maximum size of the cover plate is D2, and D1 / D2 ≥ 1 / 3.

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