A single battery and a battery pack

Abstract

This application provides a single-cell battery and a battery pack, belonging to the field of single-cell battery technology. The single-cell battery has two intersecting directions: a first direction, a second direction, and a third direction. The single-cell battery includes a casing, terminals, and an insulating diaphragm. The casing has a top cover and a bottom wall disposed opposite each other along the first direction. The terminals penetrate the top cover along the first direction towards the side opposite to the bottom wall. The insulating diaphragm wraps around the outer wall of the casing and protrudes from the top cover. The insulating diaphragm includes a first diaphragm covering the bottom wall, and the first diaphragm has at least one first through-hole penetrating along the first direction. The area of ​​the first diaphragm projected onto the bottom wall is S1, and the area of ​​the first through-hole projected onto the bottom wall is S2, satisfying 0 < S2 / S1 ≤ 1.2%. The single-cell battery provided in this application, by controlling the area occupied by the first through-hole in the first diaphragm, can not only ensure electrolyte injection efficiency but also improve the service life of the single-cell battery.

Description

Technical Field

[0001] This application relates to the field of single-cell battery technology, and more particularly to a single-cell battery and battery pack. Background Technology

[0002] With the development of new energy technologies and the increasing popularity of new energy vehicles, people's requirements for the safety of lithium-ion batteries and electric vehicles are further increasing. The large-area openings at the bottom of the insulating separators in traditional lithium-ion batteries may create lithium-ion channels at the openings. During long-term use, this can lead to corrosion of the battery casing at the openings, and in severe cases, battery leakage, which can then cause safety accidents. Utility Model Content

[0003] In view of this, the purpose of this application is to overcome the shortcomings of the prior art and provide a single cell battery and a battery pack.

[0004] This application provides the following technical solution: a single-cell battery, having a first orientation, comprising: The housing has a top cover and a bottom wall disposed opposite to each other along the first direction; Electrode assemblies are disposed within the housing; An insulating diaphragm is wrapped around a portion of the outer wall of the electrode assembly. The insulating diaphragm includes a first diaphragm facing the bottom wall, and the first diaphragm has at least one first through hole extending through the first diaphragm in the first direction for the electrolyte to flow through. Along the first direction, the area of ​​the first diaphragm projected onto the bottom wall is S1, and the area of ​​all the first through holes projected onto the bottom wall is S2, satisfying that 0 < S2 / S1 ≤ 1.2%.

[0005] In some embodiments, the first diaphragm has a plurality of spaced-apart first through holes.

[0006] In some embodiments, the single cell has a second direction and a third direction that intersect the first direction in pairs, and the first diaphragm has a first central axis parallel to the third central axis and a second central axis parallel to the second direction; The plurality of first through holes are about the first central axis, and / or the plurality of first through holes are symmetrical about the second central axis.

[0007] In some embodiments, the insulating diaphragm further includes a second diaphragm and a third diaphragm connected to the first diaphragm, the first diaphragm being located between the second diaphragm and the third diaphragm, and the second diaphragm and the third diaphragm being disposed on the outer walls of both sides of the electrode assembly along the second direction; Along the third direction, the second diaphragm has a first bending piece and a second bending piece at both ends, and the third diaphragm has a third bending piece and a fourth bending piece at both ends. The first bending piece and the third bending piece are connected and cover one side of the outer wall of the electrode assembly along the third direction, and the second bending piece and the fourth bending piece are connected and cover the other side of the outer wall of the electrode assembly along the third direction.

[0008] In some embodiments, along the second direction, the widths of the first bent piece, the second bent piece, the third bent piece, and the fourth bent piece are all smaller than the width of the housing.

[0009] In some embodiments, the single battery cell includes a base plate disposed on the side of the first diaphragm away from the housing. The first diaphragm is provided with at least two first positioning holes, and the base plate is provided with at least two second positioning holes. The axis of the first positioning hole coincides with the axis of the second positioning hole.

[0010] In some embodiments, both the first positioning hole and the second positioning hole are disposed on the first central axis.

[0011] In some embodiments, along the second direction, the distance from the axis of the first positioning hole to the edge of the first diaphragm is D1, satisfying 10mm≤D1≤30mm.

[0012] In some embodiments, the single cell includes a first sealing sheet and a second sealing sheet. Along the third direction, the first sealing sheet and the second sealing sheet are respectively disposed on the side of the insulating film away from the electrode assembly. A portion of the first sealing sheet is connected to the first film and covers the second positioning hole near the side of the first bent piece. Another portion of the first sealing sheet is connected to the first bent piece and the third bent piece. A portion of the second sealing sheet is connected to the first diaphragm and covers the second positioning hole near the side of the second bent piece, while another portion of the first sealing sheet is connected to the second bent piece and the fourth bent piece.

[0013] In some embodiments, along the second direction, the first sealing sheet at least partially covers the second diaphragm and the third diaphragm, and the second sealing sheet at least partially covers the second diaphragm and the third diaphragm.

[0014] In some embodiments, the diameter of the first through hole is 1 mm to 4 mm.

[0015] Secondly, this application provides a battery pack including the aforementioned single battery cell.

[0016] The embodiments of this application have the following advantages: by controlling the area occupied by the first through hole in the first diaphragm, not only can the liquid injection efficiency of the single cell be guaranteed, but the life of the single cell can also be improved.

[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 This diagram illustrates a structural schematic of a single-cell battery according to some embodiments of the present invention. Figure 2 This diagram illustrates a structural schematic of a single-cell battery from another perspective, according to some embodiments of the present invention. Figure 3 This diagram illustrates a structural schematic of an insulating film in a single-cell battery according to some embodiments of the present invention; Figure 4 This diagram illustrates a first embodiment of the connection between an insulating film and a base plate in a single-cell battery, according to some embodiments of the present invention. Figure 5 This diagram illustrates a second embodiment of the connection between an insulating film and a base plate in a single-cell battery, according to some embodiments of the present invention. Figure 6 This diagram illustrates a third embodiment of the connection between an insulating film and a base plate in a single-cell battery, as provided by some embodiments of the present invention. Figure 7 An exploded view of a single-cell battery provided by some embodiments of the present invention is shown; Figure 8 The diagram shows a structural schematic of a base plate in a single-cell battery according to some embodiments of the present invention.

[0020] Explanation of key component symbols: 100 - Housing; 110 - Top cover; 120 - Bottom wall; 200 - Electrode assembly; 300 - Insulating diaphragm; 310 - First diaphragm; 311 - First through hole; 320 - Second diaphragm; 330 - Third diaphragm; 340 - First bending piece; 350 - Second bending piece; 360 - Third bending piece; 370 - Fourth bending piece; 400 - Bottom support plate; 312 - First positioning hole; 410 - Second positioning hole; 500 - First sealing piece; 600 - Second sealing piece.

[0021] X - Third direction; Y - Second direction; Z - First direction; L1 - First central axis; L2 - First central axis. Detailed Implementation

[0022] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0023] It should be noted that when an element is said to be "fixed" to another element, it can be directly on the other element or there may be an intervening element. When an element is said to be "connected" to another element, it can be directly connected to the other element or there may be an intervening element. Conversely, when an element is said to be "directly" on another element, there is no intervening element. The terms "vertical," "horizontal," "left," "right," and similar expressions used in this document are for illustrative purposes only.

[0024] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0025] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0026] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the template description is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0027] like Figures 1 to 8 As shown, some embodiments of this application provide a single-cell battery with a first direction Z, which is mainly used to ensure the wettability of the electrode assembly 200 in the single-cell battery while effectively blocking lithium ions, preventing corrosion at the first through hole 311, and improving the service life of the single-cell battery.

[0028] The single cell includes a casing 100, an electrode assembly 200, and an insulating film 300.

[0029] The housing 100 has a top cover 110 and a bottom wall 120 disposed opposite to each other along the first direction Z, so as to form a receiving cavity by the top cover 110, the bottom wall 120 and the inner wall of the housing 100, and to place the electrode assembly 200 in the receiving cavity, that is, the electrode assembly 200 is disposed in the housing 100, so that the housing 100 provides protection and limitation for the electrode assembly 200, ensuring the safety and stability of the electrode assembly 200 within the housing 100.

[0030] The insulating film 300 wraps around a portion of the outer wall of the electrode assembly 200 to separate the electrode assembly 200 from the inner wall of the housing 100. This creates an insulating barrier between the electrode assembly 200 and the housing 100 to prevent short circuits from occurring when the electrode assembly 200 and the housing 100 come into contact.

[0031] In this embodiment, the insulating diaphragm 300 includes a first diaphragm 310 facing the bottom wall 120. The first diaphragm 310 has at least one first through hole 311 extending through the first direction Z for supplying electrolyte flow. It should be noted that the first direction Z can be the height direction of a single battery cell.

[0032] It is understandable that the number of first through holes 311 can be one, two or more, depending on the specific circumstances.

[0033] In some embodiments, along the first direction Z, the area of ​​the first diaphragm 310 projected onto the bottom wall 120 is S1, and the area of ​​all the first through holes 31 projected onto the bottom wall 120 is S2, satisfying 0 < S2 / S1 ≤ 1.2%. By controlling the ratio of the total area of ​​the first openings 31 to the area of ​​the first diaphragm 310, lithium ions in the electrolyte can be effectively prevented from passing through the first diaphragm 310 and contacting the casing of the individual battery, avoiding corrosion of the casing of the individual battery, and improving the service life of the individual battery while ensuring electrolyte injection efficiency and electrolyte wetting.

[0034] In some embodiments, the aperture of the first through hole 311 is 1 mm to 4 mm. It should be noted that in this embodiment, the aperture of all first through holes 311 should meet this range. Specifically, it can be 1 mm, 2 mm, 3 mm, or 4 mm. By controlling the aperture of the first through hole 311, lithium ions in the electrolyte can be effectively prevented from passing through the first membrane 310 and contacting the casing of the individual battery, thus avoiding corrosion of the casing of the individual battery and improving the lifespan of the individual battery.

[0035] Based on this, the inventors conducted multiple experiments to verify that single cells are prepared under the same system, process technology and environmental conditions, and to verify the influence of different first through-hole areas on the K value of single cells.

[0036] It should be noted that the K-value of a single battery cell typically refers to the rate of increase in static internal resistance or the rate of change in polarization impedance. It is used to assess the degree of performance degradation of a single battery cell during aging or cycle use. The smaller the K-value, the slower the increase in internal resistance and the longer the lifespan of the single battery cell; conversely, the larger the K-value, the faster the increase in internal resistance and the shorter the lifespan. The K-value is measured by monitoring the voltage change of a single battery cell over a certain period of time, and dividing the voltage difference by the time.

[0037] Table 1

[0038] Table 2

[0039] Table 3

[0040] Table 1 shows the changes in the percentage of opening area for Examples 1 to 3 and Comparative Examples 1 and 2; Table 2 shows the K-value data for Examples 1 to 3 and Comparative Examples 1 and 2; and Table 3 shows the injection time data for Examples 1 to 3 and Comparative Examples 1 and 2.

[0041] First, as shown in Tables 1 to 3 above, the ratio of the area occupied by the first through-hole 311 in the first diaphragm 310 in Example 1 is less than that in Examples 2 and 3. The K value for the corresponding time in Example 1 is less than that in Examples 2 and 3. Furthermore, the time taken from the start to the completion of electrolyte injection for a single battery in Example 1 is less than that in Examples 2 and 3. In other words, compared to the insulating diaphragm 300 where the ratio of the area of ​​the first through-hole 311 to the area of ​​the first diaphragm 310 is greater than 1.2%, this application, by controlling the area occupied by the first through-hole 311 in the first diaphragm 310, can not only shorten the electrolyte injection time and improve the electrolyte injection efficiency, but also significantly reduce the risk of battery corrosion and extend the service life of a single battery.

[0042] Secondly, compared with Comparative Example 1, the proportion of the first through hole 311 in the first membrane 310 in Comparative Example 1 is greater than that in Examples 1 to 3. Although this can shorten the injection time, the K value in Comparative Example 1 is greater than that in Examples 1 to 3, indicating that the faster the internal resistance of the electrode assembly 200 increases in Comparative Example 1, the shorter its lifespan. In contrast, the K value in Example 1 is the smallest, indicating that the slower the internal resistance of the electrode assembly 200 increases in Example 1, the longer its lifespan.

[0043] Furthermore, compared to Comparative Example 2, Comparative Example 2 does not have through holes on its first diaphragm 310, resulting in a longer liquid injection time in Comparative Example 2, which is greater than that in Example 1. Also, the K value in Example 1 and the K value in Comparative Example 2 are essentially equal, indicating that this application controls the area occupied by the first through hole 311 in the first diaphragm 310. That is, along the first direction Z, the area projected onto the bottom wall 120 by the first diaphragm 310 is S1, and the area projected onto the bottom wall 120 by all the first through holes 311 is S2, satisfying 0 < S2 / S1 ≤ 1.2%. This not only ensures the diffusion of electrolyte in the single cell, thereby ensuring the wetting ability of the electrode assembly 200 in the single cell, but also avoids the formation of lithium-ion pathways, thus preventing corrosion of the casing at the first through hole 311 and improving the service life of the single cell.

[0044] When the diameter of the first through hole is greater than 4 mm, the K value increases and the lifespan of the single cell decreases. When the diameter of the first through hole is less than 1 mm, the liquid injection time increases and the liquid injection efficiency decreases. Therefore, controlling the diameter of the first through hole within the range of 1 mm to 4 mm can improve the liquid injection efficiency and the lifespan of the single cell.

[0045] like Figure 5 and Figure 6As shown, in some embodiments of this application, the first diaphragm 310 is provided with a plurality of spaced-apart first through holes 311. The number of first through holes 311 can be any number of two or more values, and can be specifically set according to the actual situation.

[0046] In this embodiment, the arrangement of the plurality of first through holes 311 on the first diaphragm 310 includes at least one of matrix arrangement, circular array, staggered array, and gradient array.

[0047] like Figures 3 to 6 As shown, in some embodiments of this application, the single cell includes a second direction Y and a third direction X that intersect the first direction Z in pairs, and the first diaphragm 310 has a first central axis L1 parallel to the third direction X and a second central axis parallel to the second direction Y.

[0048] In this embodiment, the first direction Z, the second direction Y, and the third direction X are all perpendicular to each other.

[0049] The plurality of first through holes 311 are about the first central axis L1, and / or the plurality of first through holes 311 are symmetrical about the second central axis.

[0050] It is understood that in some embodiments, the plurality of first through holes 311 are about the first central axis L1, or the plurality of first through holes 311 are symmetrical about the second central axis. In other embodiments, the plurality of first through holes 311 are about the first central axis L1, and the plurality of first through holes 311 are symmetrical about the second central axis.

[0051] By symmetrically distributing the multiple first through holes 311 about the first central axis L1 and / or the second central axis, the multiple first through holes 311 are uniformly distributed on the first diaphragm 310, thereby ensuring the uniformity of electrolyte diffusion and improving the uniformity and efficiency of wetting of the electrode assembly 200.

[0052] like Figures 3 to 6 As shown, in some embodiments of this application, the insulating diaphragm 300 further includes a second diaphragm 320 and a third diaphragm 330 connected to the first diaphragm 310. The first diaphragm 310 is located between the second diaphragm 320 and the third diaphragm 330. The second diaphragm 320 and the third diaphragm 330 are disposed on the outer walls of both sides of the electrode assembly 200 along the second direction Y, so as to provide insulation between the electrode assembly 200 and the housing 100 through the first diaphragm 310, the second diaphragm 320 and the third diaphragm 330.

[0053] Along the third direction X, the second diaphragm 320 has a first bent piece 340 and a second bent piece 350 at both ends, and the third diaphragm 330 has a third bent piece 360 ​​and a fourth bent piece 370 at both ends. The first bent piece 340 and the third bent piece 360 ​​are connected to and cover the outer wall of the electrode assembly 200 along the third direction X, and the second bent piece 350 and the fourth bent piece 370 are connected to and cover the outer wall of the electrode assembly 200 along the other side of the third direction X, thereby allowing the first diaphragm 310 to pass through. The second diaphragm 320, the third diaphragm 330, the first bent piece 340, the second bent piece 350, the third bent piece 360, and the fourth bent piece 370 partially wrap around the electrode assembly 200, exposing the electrode assembly 200 towards the top cover 110. Thus, the insulating diaphragm 300 forms an insulating barrier between the electrode assembly 200 and the housing 100, which not only prevents short circuits from occurring when the housing 100 and the electrode assembly 200 come into contact, but also protects the electrode assembly 200 and improves its stability.

[0054] like Figures 1 to 3 As shown, in some embodiments of this application, along the second direction Y, the widths of the first bent piece 340, the second bent piece 350, the third bent piece 360, and the fourth bent piece 370 are all smaller than the width of the housing 100, to prevent the first bent piece 340 and the second bent piece 350 from partially connecting with the third diaphragm 330, and to prevent the third bent piece 360 ​​and the fourth bent piece 370 from partially connecting with the second diaphragm 320, thereby ensuring the uniformity of the peripheral thickness of the electrode assembly 200, that is, ensuring the uniformity of the thickness of the insulating film 300.

[0055] Secondly, the width of the first bending piece 340 or the width of the third bending piece 360 ​​is equal to or greater than half the width of the housing 100, and the width of the second bending piece 350 or the width of the fourth bending piece 370 is equal to or greater than half the width of the housing 100, so as to ensure that the first bending piece 340 can connect with the third bending piece 360 ​​and wrap around the outer wall of the electrode assembly 200 along the third direction X, and to ensure that the second bending piece 350 can connect with the fourth bending piece 370 and wrap around the outer wall of the electrode assembly 200 along the third direction X.

[0056] like Figure 1 , Figure 4 and Figure 8As shown, in some embodiments of this application, the single battery includes a base plate 400, which is disposed on the side of the first diaphragm 310 away from the housing 100. The first diaphragm 310 is provided with at least two first positioning holes 312 through it along the first direction Z. It can be understood that the number of first positioning holes 312 can be any number of two or more, and can be specifically set according to the actual situation.

[0057] It should be noted that multiple first positioning holes 312 are arranged at intervals on the first diaphragm 310.

[0058] In addition, the base plate 400 is provided with at least two second positioning holes 410. The axis of the first positioning hole 312 coincides with the axis of the second positioning hole 410, and the number of first positioning holes 312 and the number of second positioning holes 410 are equal. One first positioning hole 312 is connected to one second positioning hole 410 to improve the efficiency, stability and assembly quality of the assembly between the insulating film 300 and the base plate 400.

[0059] like Figures 3 to 6 As shown, in some embodiments, the first positioning hole 321 and the second positioning hole 312 are both disposed on the first central axis L to facilitate positioning and heat fusion.

[0060] like Figures 3 to 6 As shown, in some embodiments of this application, along the second direction Y, the distance from the axis of the first positioning hole 312 to the edge of the first diaphragm 310 is D1, which satisfies 10mm≤D1≤30mm, so as to improve the assembly efficiency between the insulating diaphragm 300 and the base plate 400, and also reduce the risk of corrosion.

[0061] In some embodiments, the thickness of the insulating diaphragm 300 is 0.05~0.1mm. By controlling the thickness of the insulating diaphragm 300, not only can the insulation quality of the insulating diaphragm 300 between the electrode assembly 200 and the housing 100 be guaranteed, but the space occupied by the insulating diaphragm 300 in the housing 100 can also be reduced, so as to ensure the energy density of the electrode assembly 200.

[0062] like Figure 1 and Figure 2 As shown, in some embodiments of this application, the single cell includes a first sealing sheet 500 and a second sealing sheet 600. Along the third direction X, the first sealing sheet 500 and the second sealing sheet 600 are respectively disposed on the side of the insulating film 300 away from the electrode assembly 200. A portion of the first sealing sheet 500 is connected to the first film 310 and covers the second positioning hole 410 near the side of the first bent sheet 340 to prevent electrolyte from being discharged through the second positioning hole 410, thereby ensuring the safety of the electrode assembly 200.

[0063] Meanwhile, another part of the first sealing sheet 500 is connected to the first bent piece 340 and the third bent piece 360, so that the first bent piece 340 and the third bent piece 360 ​​are fixed to the side wall of the electrode assembly 200 by the sealing sheet, so as to ensure the stability of the connection between the first bent piece 340 and the third bent piece 360 ​​and the electrode assembly 200 respectively. Moreover, the first sealing sheet 500 can cover the gap between the first bent piece 340 and the third bent piece 360 ​​to prevent the housing 100 from forming current conduction with the electrode assembly 200 through the gap between the first bent piece 340 and the second bent piece 350, thus ensuring the safety of the single cell.

[0064] A portion of the second sealing sheet 600 is connected to the first diaphragm 310 and covers the second positioning hole 410 near the side of the second bent sheet 350 to prevent electrolyte from being discharged through the second positioning hole 410, thereby ensuring the safety of the electrode assembly 200.

[0065] Simultaneously, another part of the second sealing sheet 600 is connected to the second bent sheet 350 and the fourth bent sheet 370, so as to fix the second bent sheet 350 and the fourth bent sheet 370 to the side wall of the electrode assembly 200 through the sealing sheet, so as to ensure the stability of the connection between the second bent sheet 350 and the fourth bent sheet 370 and the electrode assembly 200 respectively. Moreover, the second sealing sheet 600 can cover the gap between the second bent sheet 350 and the fourth bent sheet 370 to prevent the housing 100 from forming current conduction with the electrode assembly 200 through the gap between the second bent sheet 350 and the fourth bent sheet 370, thus ensuring the safety of the single cell.

[0066] like Figure 1 and Figure 2 As shown, in some embodiments of this application, along the second direction Y, the first sealing sheet 500 at least partially covers the second diaphragm 320 and the third diaphragm 330 to improve the stability of the connection between the end of the first sealing sheet 500 near the second diaphragm 320 and the second diaphragm 320, preventing the end of the first sealing sheet 500 near the second diaphragm 320 from tilting up. At the same time, it can ensure the stability of the connection between the end of the first sealing sheet 500 near the third diaphragm 330 and the third diaphragm 330, preventing the end of the first sealing sheet 500 near the third diaphragm 330 from tilting up, thereby improving the stability of the connection between the first sealing sheet 500 and the insulating diaphragm 300.

[0067] In addition, the second sealing sheet 600 at least partially covers the second diaphragm 320 and the third diaphragm 330 to improve the stability of the connection between the end of the second sealing sheet 600 near the second diaphragm 320 and the second diaphragm 320, and to prevent the end of the second sealing sheet 600 near the second diaphragm 320 from tilting up. At the same time, it can ensure the stability of the connection between the end of the second sealing sheet 600 near the third diaphragm 330 and the third diaphragm 330, and prevent the end of the second sealing sheet 600 near the third diaphragm 330 from tilting up, thereby improving the stability of the connection between the second sealing sheet 600 and the insulating diaphragm 300.

[0068] This application provides a battery pack including the single battery cells described in any of the above embodiments.

[0069] In this embodiment, the battery pack has the structure of the single cell described in any of the above embodiments and the beneficial effects thereof, which will not be repeated here.

[0070] In all examples shown and described herein, any specific values ​​should be interpreted as merely exemplary and not as limitations; therefore, other examples of exemplary embodiments may have different values.

[0071] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0072] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these modifications and improvements all fall within the protection scope of this application.

Claims

1. A single cell having a first direction (Z), characterized in that, include: The housing (100) has a top cover (110) and a bottom wall (120) disposed opposite each other along the first direction (Z). An electrode assembly (200) is disposed within the housing (100); An insulating diaphragm (300) is wrapped around a portion of the outer wall of the electrode assembly (200). The insulating diaphragm (300) includes a first diaphragm (310) facing the bottom wall (120). The first diaphragm (310) has at least one first through hole (311) extending through the first diaphragm (310) in the first direction (Z) for the electrolyte to flow through. Along the first direction (Z), the area of ​​the first diaphragm (310) projected onto the bottom wall (120) is S1, and the area of ​​all the first through holes (311) projected onto the bottom wall (120) is S2, satisfying that 0 < S2 / S1 ≤ 1.2%.

2. The cell according to claim 1, wherein The first diaphragm (310) is provided with a plurality of spaced-apart first through holes (311).

3. The cell according to claim 2, wherein The single cell has a second direction (Y) and a third direction (X) that are perpendicular to the first direction (Z) in pairs. The first diaphragm (310) has a first central axis (L1) parallel to the third direction (X) and a second central axis (L2) parallel to the second direction (Y). The plurality of first through holes (311) are symmetrical about the first central axis (L1), and / or the plurality of first through holes (311) are symmetrical about the second central axis (L2).

4. The cell according to claim 3, wherein The insulating diaphragm (300) further includes a second diaphragm (320) and a third diaphragm (330) connected to the first diaphragm (310), the first diaphragm (310) being located between the second diaphragm (320) and the third diaphragm (330), and the second diaphragm (320) and the third diaphragm (330) being disposed on the outer walls of both sides of the electrode assembly (200) along the second direction (Y); Along the third direction (X), the second diaphragm (320) has a first bent piece (340) and a second bent piece (350) at both ends, and the third diaphragm (330) has a third bent piece (360) and a fourth bent piece (370) at both ends. The first bent piece (340) and the third bent piece (360) are connected to and cover the outer wall of the electrode assembly (200) along the third direction (X), and the second bent piece (350) and the fourth bent piece (370) are connected to and cover the outer wall of the electrode assembly (200) along the other side of the third direction (X).

5. The cell according to claim 4, wherein Along the second direction (Y), the widths of the first bent piece (340), the second bent piece (350), the third bent piece (360), and the fourth bent piece (370) are all smaller than the width of the housing (100).

6. The cell according to claim 4, wherein The single cell includes a base plate (400), which is disposed on the side of the first diaphragm (310) away from the housing (100). The first diaphragm (310) is provided with at least two first positioning holes (312), and the base plate (400) is provided with at least two second positioning holes (410). The axis of the first positioning hole (312) coincides with the axis of the second positioning hole (410).

7. The cell according to claim 6, wherein The first positioning hole (312) and the second positioning hole (410) are both located on the first central axis (L1).

8. The cell according to claim 6, wherein The single cell includes a first sealing sheet (500) and a second sealing sheet (600). Along the third direction (X), the first sealing sheet (500) and the second sealing sheet (600) are respectively disposed on the side of the insulating film (300) away from the electrode assembly (200). A portion of the first sealing sheet (500) is connected to the first film (310) and covers the second positioning hole (410) near the side of the first bent piece (340). Another portion of the first sealing sheet (500) is connected to the first bent piece (340) and the third bent piece (360). A portion of the second sealing sheet (600) is connected to the first diaphragm (310) and covers the second positioning hole (410) near the side of the second bent piece (350). Another portion of the first sealing sheet (500) is connected to the second bent piece (350) and the fourth bent piece (370).

9. The cell according to claim 8, wherein Along the second direction (Y), the first sealing sheet (500) at least partially covers the second diaphragm (320) and the third diaphragm (330), and the second sealing sheet (600) at least partially covers the second diaphragm (320) and the third diaphragm (330).

10. The cell of claim 1 wherein, The diameter of the first through hole (311) is 1mm to 4mm.

11. A battery pack, characterized by Includes the single-cell battery as described in any one of claims 1 to 10.

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