Battery cell and electric device

Abstract

The invention relates to the technical field of batteries, in particular to a battery cell and a power utilization device. The battery cell comprises a cover plate, a shell and a pole group; the cover plate comprises a cover plate body and a first plastic part, the liquid injection part comprises a surrounding wall and a bottom wall, the bottom wall and the cover plate are oppositely arranged at intervals in the length direction, and the surrounding wall is arranged around the bottom wall by at least one circle so as to define a liquid injection groove which is open to the liquid injection hole; an air passing gap is formed between one end, far away from the insulating body in the width direction, of the liquid injection part and the shell, the liquid injection part further comprises an air passing channel penetrating through the enclosure bulkhead, so that a side exhaust port is formed in the enclosure bulkhead, and the side exhaust port is connected with the liquid injection groove and the air passing gap. According to the battery cell structure, the problems that in an existing battery cell structure, electrolyte flow guide holes are generally formed below cover plate lower plastic cement to serve as exhaust holes to guide gas in the battery cell to the outside, but physical interference is easily formed between the insulating rubber tape on the surface of the pole group and the exhaust holes, then the exhaust holes are blocked, battery cell exhausting is not complete, and battery cell bulging is caused are solved.

Description

Technical Field

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

[0002] In the battery manufacturing process, the pre-charging stage and the baking stage before electrolyte filling are key processes to ensure battery performance and safety. Among them, the pre-charging process is the core link for the first charging activation of the battery cell. During this process, the electrolyte and electrode materials undergo an interfacial reaction, which inevitably generates trace amounts of gas. The baking process before electrolyte filling aims to remove moisture from the inside of the battery cell (including components such as the electrode assembly and casing) to prevent moisture from reacting with the electrolyte to generate harmful gases that affect battery performance. During this baking process, trace amounts of residual organic matter inside the battery cell and the evaporation of moisture will also generate a certain amount of gas.

[0003] To effectively expel the gas generated during the aforementioned processes, existing battery cell structures typically utilize electrolyte drainage holes located beneath the plastic under the cover plate as vents to guide the gas inside the cell to the outside, preventing gas accumulation and pressure increases. However, during cell assembly, the electrode surfaces are usually covered with insulating tape. Unfortunately, this tape is prone to misalignment, wrinkling, or over-covering, causing physical interference between the tape and the electrolyte drainage holes beneath the cover plate. This blockage of the vents leads to incomplete gas release and cell bulging. Summary of the Invention

[0004] The purpose of this application is to provide a battery cell and an electrical device, thereby solving the problem that existing battery cell structures usually have electrolyte drainage holes set under the plastic under the cover plate as venting holes to guide the gas inside the battery cell to the outside. However, the insulating tape on the surface of the electrode group and the venting holes are prone to physical interference, which can block the venting holes and cause the battery cell to bulge due to incomplete venting.

[0005] According to a first aspect of this application, a battery cell is provided, the battery cell including a cover plate, a housing and an electrode assembly, the battery cell having a length direction and a width direction that are perpendicular to each other, the cover plate covering one side of the housing in the length direction to form a receiving space for accommodating the electrode assembly; The cover plate includes a cover plate body and a first plastic part, the first plastic part being disposed inside the housing and fixed to one side of the cover plate body in the length direction; The cover plate body has a liquid injection hole that penetrates itself at one end in the width direction. The first plastic part includes an insulating body and a liquid injection part connected along the width direction. The liquid injection part is arranged opposite to the liquid injection hole. The injection section includes a surrounding wall and a bottom wall. The bottom wall and the cover plate are spaced apart and opposite to each other along the length direction. The surrounding wall is arranged around the bottom wall at least once to form an injection groove that is open to the injection hole. An air gap is formed between the end of the liquid injection section away from the insulating body in the width direction and the housing. The liquid injection section also includes an air passage that penetrates the enclosure wall to form a side exhaust port in the enclosure wall. The side exhaust port connects the liquid injection tank and the air gap.

[0006] In any of the above technical solutions, the air passage is further provided at the end of the liquid injection part away from the insulating body in the width direction.

[0007] In any of the above technical solutions, the air passage further divides the enclosure into two sections.

[0008] In any of the above technical solutions, the battery cell further includes a thickness direction, which is perpendicular to the plane defined by the length direction and the width direction. The air passage is located at the middle of the injection section in the thickness direction.

[0009] In any of the above technical solutions, the air passage extends through the bottom wall along the length direction to form a liquid passage. The liquid inlet and the side exhaust port are connected.

[0010] In any of the above technical solutions, further, in the width direction, the liquid outlet and the liquid injection hole are staggered; And / or, the liquid outlet is formed at one end of the bottom wall in the width direction away from the insulating body and is aligned with the side vent.

[0011] In any of the above technical solutions, further, in the width direction, the dimension of the liquid injection part is N, and the dimension of the air passage is n; The battery cell also has a thickness direction, which is perpendicular to the plane defined by the length direction and the width direction. In the thickness direction, the size of the liquid injection groove is M, and the size of the air passage is m. Where, 0.25≤ ≤0.5; and / or, 0.15≤ ≤0.25.

[0012] In any of the above technical solutions, the battery cell further includes a thickness direction, which is perpendicular to the plane defined by the length direction and the width direction. The enclosure includes a sloping enclosure, a first straight enclosure, and two second straight enclosures. The second straight enclosures extend along the width direction. The first straight enclosure and the sloping enclosure are opposite to each other and spaced apart along the width direction. The first straight enclosure and the sloping enclosure are respectively connected to the two ends of the second straight enclosure. The ventilation channel sequentially cuts the first straight enclosure into a first segment and a second segment. The injection section also includes two flow-guiding barriers, which are spaced apart and facing each other in the thickness direction. The flow-guiding barriers have a first end and a second end that are opposite each other in the width direction. The first ends of both flow-guiding barriers are connected to the inclined barrier. One of the two flow-guiding barriers is connected to the end of the first section near the second section, and the other of the two flow-guiding barriers is connected to the end of the second section near the first section. Viewed along the length direction, the injection hole is located between the two flow guide barriers.

[0013] In any of the above technical solutions, the two flow-guiding barriers are further arranged symmetrically about the centerline of the first plastic part in the thickness direction; And / or, the flow guide enclosure includes a first straight section, an expansion section and a second straight section connected sequentially along the width direction. Both the first straight section and the second straight section extend along the width direction. The cross-section of the expansion section perpendicular to the length direction is arc-shaped, and the arc shape wraps around the outside of the injection hole.

[0014] According to a second aspect of this application, an electrical device is provided, including a battery cell as described above.

[0015] The battery cell of this application includes a cover plate, a housing, and an electrode assembly. The battery cell has a length direction and a width direction that are perpendicular to each other. The cover plate is disposed on one side of the housing along the length direction to form a receiving space for accommodating the electrode assembly. The cover plate includes a cover plate body and a first plastic part. The first plastic part is disposed inside the housing and fixed to one side of the cover plate body along the length direction. One end of the cover plate body in the width direction has a liquid injection hole that penetrates through it. The first plastic part includes an insulating body and a liquid injection part connected along the width direction. The liquid injection part is disposed opposite to the liquid injection hole. The liquid injection part includes a surrounding wall and a bottom wall. The bottom wall is spaced apart from the cover plate along the length direction and disposed opposite to it. The surrounding wall is disposed around the bottom wall at least once to form a liquid injection groove that is open to the liquid injection hole. An air gap is formed between the end of the liquid injection part away from the insulating body in the width direction and the housing. The liquid injection part also includes an air passage that penetrates the surrounding wall to form a side exhaust port in the surrounding wall. The side exhaust port connects the liquid injection groove and the air gap.

[0016] Based on the above technical features, the beneficial effects of this application are as follows: The battery cell of this application adds an additional venting path to the original venting path (injection guide hole - injection tank - injection hole) of the cover plate. That is, an air passage is set through the wall of the injection part, and the injection tank formed by the top wall and the wall of the injection part is connected to the air passage gap formed between the end of the injection part away from the insulating body in the width direction and the shell, thereby forming a new additional venting path (air passage gap - side vent - air passage - injection tank - injection hole). With this setting, when the injection guide hole is blocked, the gas inside the battery cell can be discharged through the air passage gap - side vent - air passage - injection tank - injection hole, so as to avoid the problem of battery cell swelling caused by incomplete venting.

[0017] 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

[0018] 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.

[0019] Figure 1 A top view of the cover plate according to an embodiment of this application is shown. Figure 2 Show Figure 1 A schematic diagram of the AA cross-sectional structure; Figure 3 An exploded view of the cover plate according to an embodiment of this application is shown. Figure 4 A bottom view of the cover plate according to an embodiment of this application is shown. Figure 5 A partial structural schematic diagram of a battery cell according to an embodiment of this application is shown; Figure 6 A schematic diagram showing the exhaust path of a battery cell according to an embodiment of this application; Figure 7 A schematic diagram of the isometric structure of the first plastic part according to an embodiment of this application is shown; Figure 8 This diagram shows another isometric view of the first plastic part according to an embodiment of this application; Figure 9 A bottom view of the structure of the first plastic material according to an embodiment of this application is shown.

[0020] Icons: 100-Cover plate body; 110-Injection hole; 121-Riveting block; 122-Electrical post; 130-Second plastic part; 140-Sealing ring; 200-First plastic part; 201-Insulating body; 202-Injection section; 210-Bottom wall; 220-Enclosure wall; 221-Slanted enclosure; 222-First straight enclosure; 2221-First section; 2222-Second section; 223-Second straight enclosure; 230-Flow guide enclosure; 231-First straight section; 232-Expansion section; 233-Second straight section; 240-Gas passage; 241-Injection port; 242-Side exhaust port; 300-Electrical assembly; 400-Housing shell; 500-Gas gap; L-Length direction; W-Width direction; T-Thickness direction. Detailed Implementation

[0021] 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.

[0022] 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.

[0023] 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.

[0024] As used herein, the term “and / or” includes any one of the relevant items listed and any combination of any two or more items.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] The first aspect of this application provides a battery cell that solves the problem that existing battery cell structures typically have electrolyte drainage holes under the plastic cover as venting holes to guide gas inside the cell to the outside. However, the insulating tape on the electrode surface easily interferes with the venting holes, thus blocking them and causing incomplete venting and cell bulging. See below for reference. Figures 1 to 9 The present application describes a battery cell according to some embodiments. Furthermore, for ease of description, the hereinafter referred to as the battery cell having a length direction L, a width direction W, and a thickness direction that are perpendicular to each other.

[0031] like Figures 1 to 9 As shown, the battery cell of this application includes a cover plate, a housing 400, and an electrode assembly 300. The battery cell has a length direction L and a width direction W that are perpendicular to each other. The cover plate is disposed on one side of the housing 400 in the length direction L to form a receiving space for accommodating the electrode assembly 300. The cover plate includes a cover plate body 100 and a first plastic part 200. The first plastic part 200 is disposed inside the housing 400 and fixed to one side of the cover plate body 100 in the length direction L. One end of the cover plate body 100 in the width direction W has a through-hole injection hole 110. The first plastic part 200 includes an insulating body 201 and an injection portion 20 connected along the width direction W. 2. The liquid injection section 202 is arranged opposite to the liquid injection hole 110. The liquid injection section 202 includes a surrounding wall 220 and a bottom wall 210. The bottom wall 210 and the cover plate are spaced apart and arranged opposite each other along the length direction L. The surrounding wall 220 is arranged around the bottom wall 210 at least once to form an open liquid injection groove facing the liquid injection hole 110. An air gap 500 is formed between the end of the liquid injection section 202 away from the insulating body 201 in the width direction W and the housing 400. The liquid injection section 202 also includes an air passage 240 that penetrates the surrounding wall 220 to form a side exhaust port 242 in the surrounding wall 220. The side exhaust port 242 connects the liquid injection groove and the air gap 500.

[0032] With this configuration, the battery cell of this application adds an additional venting path to the original venting path of the cover plate (liquid injection guide hole - liquid injection tank - liquid injection hole 110). That is, an air passage 240 is provided through the enclosure wall 220 of the liquid injection part 202, and the liquid injection tank formed by the top wall of the liquid injection part 202 and the enclosure wall 220 are connected to the air passage gap 500 formed between the end of the liquid injection part 202 away from the insulating body 201 in the width direction W and the housing 400, thereby forming a new additional venting path (air passage gap 500 - side vent 242 - air passage 240 - liquid injection tank - liquid injection hole 110). With this configuration, when the liquid injection guide hole is blocked, the gas inside the battery cell can be discharged through the air passage gap 500 - side vent 242 - air passage 240 - liquid injection tank - liquid injection hole 110, so as to avoid the problem of battery cell swelling caused by incomplete venting. On the other hand, when the liquid injection process is evacuated, the liquid injection tank and the inside of the cell are connected by an additional venting path, so that the gas pressure inside the liquid injection tank and the cell is close to the same. The electrode group 300 is less likely to block the existing guide hole or the liquid inlet 241 mentioned below, thus facilitating venting.

[0033] In the embodiments of this application, such as Figures 2 to 9 As shown, the venting channel 240 is located at the end of the liquid injection section 202 in the width direction W away from the insulating body 201. In this way, the venting channel 240 can make the exhaust path closer to the housing 400, effectively shortening the length of the additional exhaust path and reducing the retention of gas between the electrode group 300 and the liquid injection tank. At the same time, it avoids the conflict between the exhaust channel and the electrolyte injection path (directly below the liquid injection hole 110), ensuring that the electrolyte flows into the electrode group 300 preferentially during liquid injection and the gas is quickly discharged during venting, further optimizing the synergy between liquid injection and venting.

[0034] Preferably, such as Figure 4 and Figure 7 As shown, the above-mentioned exhaust channel 240 cuts the enclosure 220 into two sections, thus creating an open gap in the side exhaust port 242, which greatly increases the cross-sectional area of ​​the exhaust channel and reduces the gas flow resistance.

[0035] Preferably, such as Figure 4 and Figure 7 As shown, the venting channel 240 is located in the middle of the liquid injection section 202 in the thickness direction T. In other words, the two parts formed by the venting channel 240 cutting off the above-mentioned enclosure 220 have the same size in the thickness direction T. In this way, the gas at different thickness positions inside the housing 400 can enter the exhaust channel evenly and quickly, avoiding local bulging caused by excessive local gas pressure, and improving the overall uniformity of force on the battery cell and its safety.

[0036] Preferably, such as Figure 4 and Figures 7 to 9As shown, the above-mentioned air passage 240 penetrates the bottom wall 210 along the length direction L to form a liquid passage 241, so as to realize the liquid injection tank to inject liquid into the cell through the liquid passage 241.

[0037] However, it is not limited to this. As not shown in the figure, the bottom wall 210 may also be provided with other guide holes. Optionally, there may be multiple guide holes, which may be distributed in the bottom wall 210.

[0038] Preferably, such as Figure 4 and Figures 7 to 9 As shown, the liquid inlet 241 is connected to the side vent 242, which further increases the effective venting area of ​​the liquid injection section 202 (i.e., liquid inlet 241 + side vent 242) and the liquid injection path (i.e., when the liquid inlet 241 is blocked by the electrode group 300, the electrolyte can enter the cell through the side vent 242 and the gas gap 500).

[0039] Furthermore, such as Figure 4 and Figures 7 to 9 As shown, the liquid inlet 241 is open at the end of the bottom wall 210 in the width direction W away from the insulating body 201, and is aligned with the side vent 242. Thus, the liquid inlet 241 and the side vent 242 form an open gap on the edge defined by the side of the injection section 202 in the length direction L away from the cover plate body 100 and the side in the width direction W away from the insulating body 201. This further ensures the balance of internal and external air pressure of the cell before sealing. During the cell injection process, when the guide hole on the upper surface of the electrode assembly 300 is blocked, the electrolyte can flow out from the side vent 242-vent gap, avoiding the risk of electrolyte overflow. Simultaneously, during the cell injection process, if the guide hole on the upper surface of the electrode assembly 300 is blocked without the new venting path of this application, the internal venting of the cell will be incomplete, affecting the injection volume, thus reducing the efficiency of electrolyte injection and increasing the injection time. With the addition of a new venting path, the gas inside the battery cell can be discharged through the venting gap 500-side venting port 242-venting channel 240-injection tank-injection hole 110, which can ensure complete venting inside the battery cell and thus not affect the injection volume, thereby increasing the injection efficiency.

[0040] Preferably, such as Figure 5As shown, in the width direction W, the electrolyte inlet 241 and the injection hole 110 are staggered. Thus, during electrolyte injection, the electrolyte injected into the injection tank through the injection hole 110 is first buffered and redirected by the bottom wall 210, diffuses along the tank, and then flows into the cell through the electrolyte inlet 241. This effectively avoids the electrolyte directly impacting the diaphragm below the electrolyte inlet 241 during injection, preventing excessive local stress on the diaphragm and causing it to adhere to the electrolyte inlet 241, resulting in secondary blockage. This reduces the impact force of the electrolyte on the diaphragm, decreases the probability of the diaphragm clogging the electrolyte inlet 241, and also makes the electrolyte distribution on the electrode assembly 300 more uniform, improving the charging and discharging consistency of the cell.

[0041] In an embodiment, such as Figure 4 and Figure 9 As shown, in the width direction W, the size of the liquid injection section is N, and the size of the air passage 240 is n; in the thickness direction T, the size of the liquid injection groove is M, and the size of the air passage 240 is m.

[0042] It should be noted that, as Figures 7 to 9 As shown, the aforementioned air passage 240 penetrates the bottom wall 210 along the thickness direction T. The dimension of the air passage 240 in the width direction (i.e., Figure 9 The n) shown can be understood as the dimension of the aforementioned liquid outlet 241 in the width direction. For example... Figures 7 to 9 As shown, the aforementioned air passage 240 penetrates the enclosure 220 along the width direction W, and the dimension of the aforementioned air passage 240 in the thickness direction T (i.e., Figure 9 The m shown can be understood as the dimension of the aforementioned side exhaust port 242 in the thickness direction T. Additionally, as... Figures 7 to 9 As shown, the liquid inlet 241 and the side exhaust port 242 are aligned in the thickness direction T. That is to say, the dimension of the liquid inlet 241 in the thickness direction T is also equal to the value of m.

[0043] Preferably, 0.25≤ If the size of the electrolyte inlet 241 is too large (≤0.5), it will not only cause the electrolyte to be injected too quickly, easily overflowing and impacting the electrode assembly 300, but also greatly reduce the impact resistance of the bottom wall 210. If the size is too small, the effective electrolyte flow area will be small, which will greatly affect the electrolyte injection efficiency of the cell. Controlling the size ratio of the electrolyte inlet 241 to the electrolyte inlet 241 in the width direction W within the range of 0.25-0.5 can ensure that the electrolyte inlet 241 has a sufficient electrolyte flow area, ensuring the electrolyte injection efficiency. At the same time, it not only avoids the conflict between the electrolyte inlet 241 and the electrolyte inlet 241 boundary, but also ensures the structural strength of the electrolyte injection part 202.

[0044] Refer to Table 1. Table 1 shows the monitoring of whether the immersion time of different cells meets the requirement (≤48H) and whether there is damage to the electrode sheets when the plastic layer under the cell is a constant value of 12.5mm and the value of n is different. Table 1:

[0045] Refer to Table 2. Table 2 shows the monitoring of whether the immersion time of different cells meets the requirement (≤48H) and whether there is damage to the electrode sheets when the plastic layer under the cell is a constant value of 15mm and the value of n is different. Table 2:

[0046] The examples given in Tables 1 and 2 above illustrate that when the value of n / N is in the range of 0.25 to 0.5, the cell immersion time meets the requirements and the electrode is undamaged.

[0047] Preferably, 0.15≤ ≤0.25 means that the area ratio of the injection tank to the liquid outlet 241 is controlled within the range of 0.15-0.25, which can effectively balance the liquid flow rate and the venting space (the remaining volume of the injection tank is the gas buffer space). This ensures rapid electrolyte injection while preventing gas from being unable to escape due to the injection tank being completely filled with electrolyte, thus achieving a precise match between injection efficiency and venting safety.

[0048] Refer to Table 3. Table 3 shows the results for different values ​​of m and n for the lower plastic thickness (M=12mm, N=12.5mm). The results indicate that the battery cell does not bulge under these conditions, i.e., the thickness is within the tolerance range (20±0.2mm), and the extrusion pressure of the plastic compression diaphragm meets the requirements (40N~60N). Table 3:

[0049] Refer to Table 4. Table 4 shows the results for different values ​​of m and n for the plastic diaphragm (M=13mm, N=15mm) to ensure the cell does not bulge, i.e., whether the thickness is within the tolerance range (19±0.2mm) and whether the extrusion pressure of the plastic diaphragm meets the requirements (40N~60N). Table 4:

[0050] The examples given in Tables 3 and 4 above illustrate that when Satisfying 0.15≤ When the thickness is ≤0.25, the cell thickness meets the tolerance range, and the extrusion pressure of the separator and plastic meets the range requirements.

[0051] In an embodiment, preferably, such as Figures 2 to 9As shown, the aforementioned enclosure 220 may include a sloping enclosure 221, a first straight enclosure 222, and two second straight enclosures 223. The second straight enclosures 223 extend along the width direction W. The first straight enclosure 222 and the sloping enclosure 221 are arranged opposite each other and spaced apart along the width direction W. The first straight enclosure 222 and the sloping enclosure 221 are respectively connected to the two ends of the second straight enclosure 223. The air passage 240 sequentially cuts the first straight enclosure 222 into a first segment 2221 and a second segment 2222 (in conjunction with the above "the air passage 240 is located at the liquid injection section 202 in the width direction W of the far... The inclined baffle 221 is provided along the edge of the bottom wall 210 on the side closest to the insulating body 201. In this way, on the one hand, by providing the inclined baffle 221 to connect the insulating body 201 and the bottom wall 210, the electrolyte can be effectively guided to the bottom of the injection tank, reducing the risk of electrolyte overflowing into the insulating body 201. On the other hand, the straight baffle provided at both ends of the thickness direction T and the end of the width direction W away from the insulating body 201 of the injection part 202 can facilitate the positioning of the first plastic part 200.

[0052] Preferably, such as Figure 3 , Figure 7 and Figure 9 As shown, the injection section 202 also includes two flow guide barriers 230. The two flow guide barriers 230 are spaced apart and facing each other in the thickness direction T. The flow guide barriers 230 have a first end and a second end that are opposite each other in the width direction W. The first end of both flow guide barriers 230 is connected to the inclined barrier 221. One of the two flow guide barriers 230 is connected to the end of the first section 2221 near the second section 2222, and the other of the two flow guide barriers 230 is connected to the end of the second section 2222 near the first section 2221. Observed along the length direction L, the above-mentioned injection hole 110 is located between the two above-mentioned flow guides 230. In this way, the two flow guides 230 form a directional flow channel in the injection tank, guiding the electrolyte from the inclined barrier 221 side to the liquid outlet 241, avoiding local accumulation caused by disordered diffusion of electrolyte in the injection tank; at the same time, the gap between the flow guides 230 can guide the gas to converge towards the side exhaust port 242, further improving the directionality of liquid flow and exhaust, and reducing mutual interference.

[0053] Preferably, such as Figure 7 and Figure 9 As shown, the two flow guide barriers 230 are positioned about the centerline of the first plastic part 200 in the thickness direction T (e.g., Figure 1As shown in the figure (the dotted line in the figure is the center line), the electrolyte flow and gas diffusion in the injection tank are symmetrically arranged, so that the electrolyte flow and gas diffusion in the injection tank are symmetrically distributed, avoiding problems such as excessive / insufficient electrolyte and gas retention in some areas of the electrode group 300 caused by asymmetrical flow channels, ensuring the consistency of electrochemical reaction in each area of ​​the electrode group 300, and improving the cycle life and capacity stability of the cell.

[0054] Preferably, such as Figure 7 and Figure 9 As shown, the flow guide barrier 230 may include a first straight section 231, an expansion section 232, and a second straight section 233 connected sequentially along the width direction W. Both the first straight section 231 and the second straight section 233 extend along the width direction W. The cross-section of the expansion section 232 perpendicular to the length direction L is arc-shaped, and the arc shape wraps around the outside of the injection hole 110. In this way, the arc-shaped expansion section 232 increases the space in the middle of the injection tank, which on the one hand provides a buffer area for the electrolyte and reduces the impact pressure during injection; on the other hand, it expands the gas gathering space and reduces the gas flow resistance. At the same time, the straight section ensures the directional guidance of the electrolyte to the liquid outlet 241, and the arc-shaped section avoids turbulence caused by abrupt changes in the flow channel, making the electrolyte flow smoother and further improving the injection efficiency.

[0055] In summary, the battery cell of this application adds an additional venting path to the original venting path of the cover plate (liquid injection guide hole - liquid injection tank - liquid injection hole 110). That is, an air passage 240 is provided through the enclosure wall 220 of the liquid injection part 202, and the liquid injection tank formed by the top wall of the liquid injection part 202 and the enclosure wall 220 are connected to the air passage gap 500 formed between the end of the liquid injection part 202 away from the insulating body 201 in the width direction W and the housing 400, thereby forming a new additional venting path (air passage gap 500 - side vent 242 - air passage 240 - liquid injection tank - liquid injection hole 110). With this configuration, when the liquid injection guide hole is blocked, the gas inside the battery cell can be discharged through the air passage gap 500 - side vent 242 - air passage 240 - liquid injection tank - liquid injection hole 110, so as to avoid the problem of battery cell swelling caused by incomplete venting. On the other hand, when the liquid injection process is evacuated, the liquid injection tank and the inside of the cell are connected by an additional venting path, so that the gas pressure inside the liquid injection tank and the cell is close to the same. The electrode group 300 is less likely to block the existing guide hole or the liquid inlet 241 mentioned below, thus facilitating venting.

[0056] In addition, the cover plate of this application also includes a pole post 122, a second plastic part 130, a sealing ring 140 and a riveting block 121. The pole post 122 passes through the through holes of the first plastic part 200, the cover plate body 100, the sealing ring 140, the second plastic part 130 and the riveting block 121 in sequence, and is riveted to the riveting block 121.

[0057] According to a second aspect of this application, an electrical device is provided, including a battery cell as described above.

[0058] 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 battery cell, characterized in that, The battery cell includes a cover plate, a housing, and an electrode assembly. The battery cell has a length direction and a width direction that are perpendicular to each other. The cover plate is disposed on one side of the housing in the length direction to form a receiving space for accommodating the electrode assembly. The cover plate includes a cover plate body and a first plastic part, the first plastic part being disposed inside the housing and fixed to one side of the cover plate body in the length direction; The cover plate body has a liquid injection hole that penetrates itself at one end in the width direction. The first plastic part includes an insulating body and a liquid injection part connected along the width direction. The liquid injection part is arranged opposite to the liquid injection hole. The injection section includes a surrounding wall and a bottom wall. The bottom wall and the cover plate are spaced apart and opposite to each other along the length direction. The surrounding wall is arranged around the bottom wall at least once to form an injection groove that is open to the injection hole. An air gap is formed between the end of the liquid injection section away from the insulating body in the width direction and the housing. The liquid injection section also includes an air passage that penetrates the enclosure wall to form a side exhaust port in the enclosure wall. The side exhaust port connects the liquid injection tank and the air gap.

2. The battery cell according to claim 1, characterized in that, The air passage is located at the end of the liquid injection section away from the insulating body in the width direction.

3. The battery cell according to claim 2, characterized in that, The air passage cuts the enclosure into two sections.

4. The battery cell according to claim 3, characterized in that, The battery cell also has a thickness direction, which is perpendicular to the plane defined by both the length direction and the width direction; The air passage is located at the middle of the injection section in the thickness direction.

5. The battery cell according to claim 1, characterized in that, The air passage extends through the bottom wall along the length direction to form a liquid passage. The liquid inlet and the side exhaust port are connected.

6. The battery cell according to claim 5, characterized in that, In the width direction, the liquid outlet is offset from the liquid injection hole; And / or, the liquid outlet is formed at one end of the bottom wall in the width direction away from the insulating body and is aligned with the side vent.

7. The battery cell according to claim 1, characterized in that, In the width direction, the dimension of the injection section is N, and the dimension of the air passage is n; The battery cell also has a thickness direction, which is perpendicular to the plane defined by the length direction and the width direction. In the thickness direction, the size of the liquid injection groove is M, and the size of the air passage is m. Where, 0.25≤ ≤0.5; and / or, 0.15≤ ≤0.

25.

8. The battery cell according to claim 3, characterized in that, The battery cell also has a thickness direction, which is perpendicular to the plane defined by both the length direction and the width direction; The enclosure includes a sloping enclosure, a first straight enclosure, and two second straight enclosures. The second straight enclosures extend along the width direction. The first straight enclosure and the sloping enclosure are opposite to each other and spaced apart along the width direction. The first straight enclosure and the sloping enclosure are respectively connected to the two ends of the second straight enclosure. The ventilation channel sequentially cuts the first straight enclosure into a first segment and a second segment. The injection section also includes two flow-guiding barriers, which are spaced apart and facing each other in the thickness direction. The flow-guiding barriers have a first end and a second end that are opposite each other in the width direction. The first ends of both flow-guiding barriers are connected to the inclined barrier. One of the two flow-guiding barriers is connected to the end of the first section near the second section, and the other of the two flow-guiding barriers is connected to the end of the second section near the first section. Viewed along the length direction, the injection hole is located between the two flow guide barriers.

9. The battery cell according to claim 8, characterized in that, The two flow-guiding barriers are symmetrically arranged about the centerline of the first plastic part in the thickness direction; And / or, the flow-guiding barrier includes a first straight section, an expansion section and a second straight section connected sequentially along the width direction, the first straight section and the second straight section both extending along the width direction, the cross-section of the expansion section perpendicular to the length direction is arc-shaped, and the arc shape wraps around the outside of the injection hole.

10. An electrical device, characterized in that, Includes the battery cell as described in any one of claims 1-9.

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