Single battery and battery pack

Abstract

The utility model discloses a single battery and a battery pack. The single battery comprises a shell, at least two battery cell assemblies, a plurality of connecting pieces, a top cover and a plurality of pole assemblies, the shell is provided with an accommodating cavity; the at least two battery cell assemblies are placed in the accommodating cavity, are insulated from each other, and are provided with positive tabs and negative tabs; each positive tab is correspondingly connected with a connecting piece, the connecting pieces on different positive tabs are mutually isolated, each negative tab is correspondingly connected with a connecting piece, and the connecting pieces on different negative tabs are mutually isolated; the top cover is connected with the shell to cover the accommodating cavity, and a plurality of pole holes are formed in the top cover; and the plurality of pole assemblies respectively penetrate through the plurality of pole holes, are connected with the plurality of connecting sheets one by one, and are isolated from one another. In the detection process, whether the performance of a single battery cell assembly is abnormal or not is judged for the pole column assembly corresponding to each battery cell assembly, so that accurate positioning is realized, and targeted treatment or improvement is carried out.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, in particular to a single cell and a battery pack. Background Art

[0002] Power batteries are a crucial energy source for electric vehicles, and their performance directly impacts their range and safety. Power batteries consist of cells and tabs extending from the cells, including positive and negative tabs. Flexible connectors are located on the inner side of the top cover, while posts are located on the outer side. These posts connect to the tabs via the flexible connectors, effectively enabling the cell's charge and discharge functions.

[0003] Dual-core pack power battery cells are usually composed of a single or two core packs. For battery cells, in the existing technology, the battery cells are usually combined together by welding a single soft connector to the positive and negative electrodes of the two core packs respectively. There are some problems with this structure. If the battery fails during use, it is impossible to determine which core pack in the battery has a problem, so it is impossible to accurately locate the specific core pack and trace the failure batch corresponding to the core pack, which brings great difficulties to the maintenance and improvement of the battery. In addition, since it is impossible to accurately determine which core pack has a problem, it is impossible to effectively optimize the battery, which may affect the service life and safety of the battery. Therefore, how to design a method that can accurately locate the specific core pack in the dual-core pack battery cell for targeted processing or improvement is an urgent problem to be solved in the current power battery design field. Utility Model Content

[0004] One purpose of the present utility model is to provide a single battery and a module, which aims to solve the technical problem of being unable to accurately determine which core pack has a problem.

[0005] To achieve the above-mentioned purpose, the present invention provides a solution: a single battery, which includes a shell, at least two battery cell assemblies, multiple connecting plates, a top cover and multiple pole assemblies; the shell is provided with a accommodating cavity; at least two battery cell assemblies are placed in the accommodating cavity, at least two battery cell assemblies are insulated from each other, and the battery cell assembly has a positive electrode ear and a negative electrode ear; each positive electrode ear is correspondingly connected to a connecting plate, and the connecting plates on different positive electrodes are isolated from each other, and each negative electrode ear is correspondingly connected to a connecting plate, and the connecting plates on different negative electrodes are isolated from each other; the top cover is connected to the shell to cover the accommodating cavity, and the top cover is provided with multiple pole holes; multiple pole assemblies are respectively penetrated by multiple pole holes, multiple pole assemblies are connected one by one to multiple connecting plates, and multiple pole assemblies are isolated from each other.

[0006] Optionally, the single battery cell further includes a plurality of terminals, and the pole assemblies corresponding to the positive tabs are electrically connected via the terminals, and the pole assemblies corresponding to the negative tabs are electrically connected via the terminals.

[0007] Optionally, the terminal and pole assembly are detachably connected.

[0008] Optionally, the terminal is provided with a limiting slot, and the conductive end of the pole assembly is assembled in the limiting slot.

[0009] Optionally, the terminal includes a top wall and side walls, the side walls are arranged around the top wall to form an assembly cavity, the side walls are connected to the peripheral side surfaces of the pole assembly, the top wall is provided with a limiting groove, and the pole assembly is assembled in the assembly cavity.

[0010] Optionally, the single cell further includes a conductive paste, and the conductive paste is disposed in the limiting groove.

[0011] Optionally, the single battery further includes an elastic ejector pin, which is elastically arranged between the side wall and the peripheral side surface of the pole assembly, and / or the elastic ejector pin is elastically arranged between the top wall and the conductive end of the pole assembly.

[0012] Optionally, a first thread structure is provided on the peripheral side surface of the pole assembly, and a second thread structure is provided on the terminal. The terminal and the plurality of pole assemblies are rotatably connected so that the first thread structure and the second thread structure cooperate.

[0013] Optionally, the connecting piece includes a connecting end and a transition end connected to each other, the surface area of ​​the connecting end is larger than the surface area of ​​the transition end, the connecting end is connected to the positive electrode ear or the negative electrode ear, and the transition end is connected to the pole assembly.

[0014] To achieve the above-mentioned object, the present invention provides a solution: a battery pack, characterized in that the battery pack comprises: a box body and a plurality of single cells as described above, wherein the plurality of single cells are arranged in the box body.

[0015] The beneficial effects of the present invention are:

[0016] The single battery includes a shell, at least two battery cell assemblies, multiple connecting plates, a top cover, and multiple pole assemblies. The shell is provided with a receiving cavity, and the receiving cavity has an opening communicating with the outside world. At least two battery cell assemblies are placed in the receiving cavity, and at least two battery cell assemblies are insulated from each other. Each battery cell assembly has a positive electrode ear and a negative electrode ear. Each battery cell assembly can be powered as an independent individual. The battery cell assembly is formed by stacking or winding positive electrode sheets, diaphragms, and negative electrode sheets. The positive electrode ear on each battery cell assembly is connected to a corresponding connecting plate, and the connecting plates on different positive electrode ears are isolated from each other so as not to be electrically conductive to each other. The negative electrode ear on each battery cell assembly is connected to a corresponding connecting plate, and the connecting plates on different negative electrode ears are isolated from each other and do not contact each other so as not to be electrically conductive to each other. Of course, the connecting plates on the positive electrode ear and the connecting plates on the negative electrode ear are also isolated from each other and do not contact each other to prevent short circuits.

[0017] The top cover is connected to the shell to cover the accommodating cavity. The top cover is provided with multiple pole holes, including positive pole holes and negative pole holes. Multiple pole assemblies are respectively provided with multiple pole holes. There are multiple positive pole assemblies, which pass through the positive pole holes. There are multiple negative pole assemblies, which pass through the negative pole holes. The multiple pole assemblies are connected one by one to multiple connecting pieces. The multiple pole assemblies are isolated from each other. Each positive pole assembly is connected to a connecting piece on each positive electrode ear, and the positive pole assembly is electrically conductive with the corresponding battery cell assembly. Each negative pole assembly is connected to a connecting piece on each negative electrode ear, and the negative pole assembly is electrically conductive with the corresponding battery cell assembly. The pole assemblies corresponding to the positive electrode ears are insulated from each other, and the pole assemblies corresponding to the negative electrode ears are insulated from each other.

[0018] During use, the multiple positive and negative electrode assemblies of a single battery are independent conductive components that can be electrically conductive. During testing, the positive and negative electrode assemblies corresponding to each battery cell are connected to determine whether the performance of the individual cell assembly is abnormal. This allows accurate identification of the problem with the specific cell assembly in the single battery cell, allowing for targeted treatment or improvement. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0020] Figure 1 This is a schematic diagram of the assembly structure of a single cell provided by an embodiment of the present utility model;

[0021] Figure 2 This is a schematic diagram of the exploded structure of a single cell provided by an embodiment of the present utility model;

[0022] Figure 3 This is a cross-sectional schematic diagram of an embodiment of a single cell provided by an embodiment of the present utility model;

[0023] Figure 4 The embodiment of the present utility model provides Figure 3 A partial enlarged schematic diagram of area A in the middle;

[0024] Figure 5 This is a schematic top view of the structure of a single cell provided by an embodiment of the utility model;

[0025] Figure 6It is a cross-sectional schematic diagram of another embodiment of a single cell provided by an embodiment of the present utility model;

[0026] Figure 7 The embodiment of the present utility model provides Figure 6 A partial enlarged schematic diagram of area B in the middle;

[0027] Figure 8 It is a structural schematic diagram of the connecting piece provided by an embodiment of the utility model.

[0028] Description of the accompanying drawings: shell 10, accommodating cavity 101, battery cell assembly 20, positive electrode ear 21, negative electrode ear 22; connecting piece 30, connecting end 31, transition end 33, top cover 40, pole hole 401, pole assembly 50; terminal 60, limiting groove 601, top wall 61, side wall 63, elastic ejector pin 70. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0030] See also Figures 1 to 4 As shown, Figure 1 This is a schematic diagram of the assembly structure of a single battery provided by an embodiment of the utility model. Figure 2 This is a schematic diagram of the exploded structure of a single battery provided by an embodiment of the present utility model. Figure 3 This is a cross-sectional schematic diagram of an embodiment of a single cell provided by an embodiment of the present utility model. Figure 4 The embodiment of the present utility model provides Figure 3 A partial enlarged schematic diagram of area A in the middle.

[0031] The present invention provides a single battery cell comprising a housing 10, at least two battery cell assemblies 20, a plurality of connecting tabs 30, a top cover 40, and a plurality of terminal assemblies 50. The housing 10 is provided with a housing cavity 101 having an opening communicating with the outside world. At least two battery cell assemblies 20 are placed in the housing cavity 101. The at least two battery cell assemblies 20 are insulated from each other. Each battery cell assembly 20 has a positive tab 21 and a negative tab 22. Each battery cell assembly 20 can be independently powered. The battery cell assembly 20 is formed by stacking or winding positive electrode sheets, separators, and negative electrode sheets. The positive tab 21 on each battery cell assembly 20 is connected to a corresponding connecting piece 30, and the connecting pieces 30 on different positive tabs 21 are isolated from each other so as not to be electrically conductive to each other. The negative tab 22 on each battery cell assembly 20 is connected to a corresponding connecting piece 30, and the connecting pieces 30 on different negative tabs 22 are isolated from each other and do not contact each other so as not to be electrically conductive to each other. Of course, the connecting pieces 30 on the positive tab 21 and the connecting pieces 30 on the negative tab 22 are also isolated from each other and do not contact each other to prevent short circuits.

[0032] The top cover 40 is connected to the housing 10 to cover the accommodating cavity 101. The top cover 40 is provided with a plurality of pole holes 401, including both positive and negative pole holes. Multiple pole assemblies 50 are respectively provided with the plurality of pole holes 401. There are multiple positive pole assemblies 50, each of which passes through the positive pole holes, and there are multiple negative pole assemblies 50, each of which passes through the negative pole holes. The multiple pole assemblies 50 are connected one by one to the multiple connecting pieces 30. The multiple pole assemblies 50 are isolated from each other. Each positive pole assembly 50 is connected to a corresponding connecting piece 30 on each positive tab 21, and the positive pole assembly 50 is individually electrically connected to the corresponding battery cell assembly 20. Each negative pole assembly 50 is connected to a corresponding connecting piece 30 on each negative tab 22, and the negative pole assembly 50 is individually electrically connected to the corresponding battery cell assembly 20. The pole assemblies 50 corresponding to the positive tab 21 are insulated from each other, and the pole assemblies 50 corresponding to the negative tab 22 are insulated from each other.

[0033] In this embodiment, during use, the multiple positive electrode post assemblies 50 and the multiple negative electrode post assemblies 50 of the single battery are independent conductive components, and the multiple positive electrode post assemblies 50 can be electrically conductive, and the multiple negative electrode post assemblies 50 can be electrically conductive. During the testing process, the positive electrode post assembly 50 and the negative electrode post assembly 50 corresponding to each battery cell assembly 20 are connected to determine whether the performance of the individual battery cell assembly 20 is abnormal, thereby accurately locating the problem of the specific battery cell assembly 20 in the single battery cell, so as to implement targeted treatment or improvement.

[0034] The single cell also includes a plurality of terminals 60. The material of the terminals 60 can be copper, aluminum, iron, and alloys thereof. The terminals 60 have conductive properties. The pole assemblies 50 corresponding to the positive tabs 21 are electrically connected through the terminals 60, and the pole assemblies 50 corresponding to the negative tabs 22 are electrically connected through the terminals 60. A portion of the terminals 60 connects the pole assemblies 50 corresponding to the positive tabs 21 in parallel, and another portion of the terminals 60 connects the pole assemblies 50 corresponding to the positive tabs 21 in parallel. During the production process of the single cell, multiple positive pole assemblies 50 and multiple negative pole assemblies 50 are electrically connected in advance through the terminals 60. In this way, during the later use of the single cell, the single cell of the present application can be directly connected in series or in parallel with other single cells, saving usage time. When a fault occurs in the later stage and needs to be detected, it is only necessary to remove the terminal 60 to start the electrical detection of the pole assemblies 50 corresponding to each battery cell assembly 20.

[0035] The terminal 60 and the pole assembly 50 are detachably connected. This detachable connection specifically means that the terminal 60 and the pole assembly 50 can be manually removed, making it easier to quickly remove the terminal 60 from the pole assembly 50 during later single-cell battery failure detection. Examples of detachable connections include snap-fit ​​connections, threaded connections, adhesive bonding, and interference fit.

[0036] See also Figure 5 As shown, Figure 5 It is a schematic top view of the structure of a single cell provided in an embodiment of the utility model.

[0037] Among them, the present application prefers a threaded connection. Specifically, a first thread structure is provided on the peripheral side surface of the pole assembly 50, and a second thread structure is also provided on the terminal 60. The multiple pole assemblies 50 corresponding to the positive ear 21 constitute a whole, and the pitch and thread direction of the first thread structure on each pole assembly 50 are the same, thereby forming a new first thread structure in combination, and the terminal 60 rotates relative to it. The multiple pole assemblies 50 corresponding to the negative ear 22 constitute a whole, and the terminal 60 rotates relative to it, and the pitch and thread direction of the first thread structure on each pole assembly 50 are the same, thereby forming a new first thread structure in combination. In this way, during the rotation of the terminal 60 relative to the multiple pole assemblies 50, the inner boundary of the terminal 60 is tangent or approximately tangent to the outer boundary of the whole formed by the multiple pole assemblies 50, the first thread structure and the second thread structure cooperate together, and the terminal 60 and the pole assembly 50 are threadedly connected.

[0038] When the terminal 60 is square, it can be rotated in multiples of 90 degrees. When the terminal 60 is circular, it can be rotated at any angle until it cannot be rotated any further. During assembly or disassembly, only the terminal 60 needs to be rotated, without damaging the connection between the terminal 60 and the pole assembly 50. Furthermore, during rotation, the preload force between the terminal 60 and the pole assembly 50 can be adjusted to ensure stable electrical continuity between the terminal 60 and the pole assembly 50.

[0039] Furthermore, the terminal 60 may be in a circular structure, and the plurality of positive electrode post assemblies 50 also form a circular structure, and the plurality of negative electrode post assemblies 50 also form a circular structure. This facilitates the rotation of the terminal 60 relative to the positive electrode post assembly 50 and the negative electrode post assembly 50.

[0040] Please continue reading Figures 1 to 4 In one embodiment, the terminal 60 is provided with a limiting groove 601, and the conductive end of the pole assembly 50 is assembled in the limiting groove 601. Under normal circumstances, in order to facilitate conduction, the conductive end of the pole assembly 50 is located on the top surface and the area surrounding the top surface. The terminal 60 is matched with the pole assembly 50 through the limiting groove 601. The limiting groove 601 can not only prevent the terminal 60 from shaking relative to the pole assembly 50 and causing poor contact, but also ensure that the conductive end of the pole assembly 50 and the terminal 60 always maintain contact and conduction. It can be understood that each pole assembly 50 corresponds to a limiting groove 601, and the number of pole assemblies 50 that each terminal 60 needs to connect is the number of limiting grooves 601 that should be opened on the terminal 60. The number of limiting grooves 601 shown in the accompanying drawings is two. The pole assembly 50 can be detachably connected together by means of an interference fit between the limiting groove 601.

[0041] See also Figure 6 and Figure 7 As shown, Figure 6 This is a cross-sectional schematic diagram of another embodiment of a single cell provided by an embodiment of the present utility model. Figure 7 The embodiment of the present utility model provides Figure 6 A partial enlarged schematic diagram of area B in the middle.

[0042] In one embodiment, the terminal 60 includes a top wall 61 and a side wall 63. The side wall 63 is arranged around the top wall 61 to form an assembly cavity. The cross-sectional shape of the terminal 60 is U-shaped. The terminal 60 is similar to a hat. The side wall 63 is connected to the peripheral side of the pole assembly 50. The top wall 61 is provided with a limiting groove 601, and the pole assembly 50 is assembled in the assembly cavity. The assembly cavity is similar to a large limiting space that covers multiple pole assemblies 50. The side wall 63 abuts against the peripheral side of the pole assembly 50, thereby further limiting the terminal 60, further preventing the terminal 60 from shaking relative to the pole assembly 50 and causing poor contact, and can ensure that the conductive end of the pole assembly 50 and the terminal 60 always maintain contact and conduction. In addition, the assembly cavity can isolate external dust and liquid from entering the contact point between the terminal 60 and the pole assembly 50, preventing poor contact.

[0043] Furthermore, the single cell battery also includes a conductive paste, which is disposed in the retaining groove 601. Electrical composite grease, also known as conductive paste, is a neutral conductive dressing with excellent electrical contact properties. It is suitable for use on the contact surfaces of high- and low-voltage electrical busbars and various electrical connectors, significantly reducing contact resistance and thus achieving excellent energy-saving economic benefits. The conductive paste is filled in the retaining groove 601, and the conductive end of the pole assembly 50 is assembled in the retaining groove 601. The conductive paste fills the tiny gap between the conductive end and the retaining groove 601. This not only reduces the on-resistance between the two, but also improves the conduction efficiency and avoids energy waste.

[0044] Furthermore, the single cell further includes an elastic ejector pin 70, which is elastically disposed between the side wall 63 and the peripheral side surface of the electrode assembly 50, and / or between the top wall 61 and the conductive end of the electrode assembly 50. This embodiment includes three scenarios: 1: the elastic ejector pin 70 is elastically disposed between the side wall 63 and the peripheral side surface of the electrode assembly 50; 2: the elastic ejector pin 70 is elastically disposed between the top wall 61 and the conductive end of the electrode assembly 50; and 3: the elastic ejector pin 70 is elastically disposed between the side wall 63 and the peripheral side surface of the electrode assembly 50, and between the top wall 61 and the conductive end of the electrode assembly 50.

[0045] The elastic ejector pin 70 is elastic and can retract to accumulate elastic force when subjected to external force. It can recover its deformation by relying on the elastic force after the external force disappears. The specific structure of the elastic ejector pin 70 is composed of a metal block and a spring.

[0046] When the elastic ejector pin 70 is arranged on the peripheral side surface of the pole assembly 50, the static friction force of the contact between the two can not only ensure the detachable connection between the terminal 60 and the pole assembly 50, but also when the terminal 60 swings left and right, the elastic ejector pin 70 can still rely on the elastic force to support the terminal 60, thereby improving the conductive efficiency.

[0047] When the elastic ejector pin 70 is arranged on the top surface of the pole assembly 50 , when the terminal 60 swings up and down, the elastic ejector pin 70 can still be held on the terminal 60 by elastic force, thereby improving the conductive efficiency.

[0048] See also Figure 1 、 Figure 2 and Figure 8 As shown, Figure 8 It is a structural diagram of the connecting piece 30 provided in an embodiment of the present utility model.

[0049] The connecting piece 30 can be made of copper, aluminum, iron, or alloys thereof. The connecting piece 30 has conductive properties. The connecting piece 30 connected to the positive electrode tab 21 is the positive electrode connecting piece 30, and the connecting piece 30 connected to the negative electrode tab 22 is the negative electrode connecting piece 30. Each positive electrode tab 21 is connected to a positive electrode connecting piece 30, and each negative electrode tab 22 is connected to a negative electrode connecting piece 30. The connecting piece 30 can be a thin plate-like hard structure or a soft structure.

[0050] Specifically, the connecting piece 30 includes a connecting end 31 and a transition end 33, which are connected to each other. The surface area of ​​the connecting end 31 is larger than that of the transition end 33. The connecting end 31 is connected to the positive electrode tab 21 or the negative electrode tab 22, and the transition end 33 is connected to the terminal assembly 50. The larger surface area of ​​the connecting end 31 than the transition end 33 allows the connecting piece 30 to have a sufficient area to connect to the positive electrode tab 21 or the negative electrode tab 22, thereby ensuring normal electrical conduction and reducing resistance and heat generation at the location of the connecting end 31.

[0051] The present application also protects a battery pack, which includes a box and multiple single cells as described in any of the above embodiments. The multiple single cells are arranged in the box, and the multiple single cells can be connected in series, in parallel, or in a mixed series-parallel connection.

[0052] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship and movement status of the various components in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0053] It should also be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it may be directly connected to the other element or indirectly connected to the other element through an intervening element.

[0054] In addition, the descriptions of "first," "second," etc. in this utility model are for descriptive purposes only and should not be understood as indicating or implying their relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of such features. In addition, the technical solutions between the various embodiments can be combined with each other, but this must be based on the fact that they can be implemented by ordinary technicians in this field. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by this utility model.

[0055] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made by using the contents of the present invention specification and drawings under the utility model concept, or direct / indirect application in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A single battery, characterized in that: include: The housing is provided with a receiving cavity; At least two battery cell assemblies are placed in the accommodating cavity, the at least two battery cell assemblies are insulated from each other, and the battery cell assemblies have a positive electrode tab and a negative electrode tab; A plurality of connecting pieces, each positive electrode tab is connected to a corresponding connecting piece, and the connecting pieces on different positive electrode tabs are isolated from each other; each negative electrode tab is connected to a corresponding connecting piece, and the connecting pieces on different negative electrode tabs are isolated from each other; A top cover connected to the shell to cover the accommodating cavity, and the top cover is provided with a plurality of pole holes; as well as A plurality of pole assemblies are respectively provided with the plurality of pole holes, the plurality of pole assemblies are connected to the plurality of connecting pieces in a one-to-one correspondence, and the plurality of pole assemblies are isolated from each other.

2. The single cell according to claim 1, characterized in that: The single battery further includes a plurality of terminals, through which the pole assemblies corresponding to the positive tabs are electrically connected, and the pole assemblies corresponding to the negative tabs are electrically connected.

3. The single cell according to claim 2, characterized in that: The terminal and the pole assembly are detachably connected.

4. The single cell according to claim 2, characterized in that: The terminal is provided with a limiting slot, and the conductive end of the pole assembly is assembled in the limiting slot.

5. The single cell according to claim 4, characterized in that: The terminal includes a top wall and side walls, the side walls are arranged around the top wall to form an assembly cavity, the side walls are connected to the peripheral side surfaces of the pole assembly, the top wall is provided with the limiting groove, and the pole assembly is assembled in the assembly cavity.

6. The single cell according to claim 4, characterized in that: The single battery further includes a conductive paste, which is disposed in the limiting groove.

7. The single cell according to claim 5, characterized in that: The single battery further includes an elastic ejector pin, which is elastically arranged between the side wall and the peripheral side surface of the pole assembly, and / or the elastic ejector pin is elastically arranged between the top wall and the conductive end of the pole assembly.

8. The single cell according to claim 3, characterized in that: A first thread structure is provided on the peripheral side surface of the pole assembly, and the terminal is provided with a second thread structure. The terminal and the plurality of pole assemblies are rotatably connected so that the first thread structure and the second thread structure cooperate with each other.

9. The single cell according to claim 1, characterized in that: The connecting piece includes a connecting end and a transition end connected to each other, the surface area of ​​the connecting end is larger than the surface area of ​​the transition end, the connecting end is connected to the positive electrode ear or the negative electrode ear, and the transition end is connected to the pole assembly.

10. A battery pack, characterized in that: The battery pack includes: a case and a plurality of single batteries according to any one of claims 1 to 9, wherein the plurality of single batteries are arranged in the case.

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