Single battery and battery pack

Abstract

The invention 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 the single battery cell assembly is abnormal or not is judged for the pole assembly corresponding to each battery cell assembly, so that accurate positioning is achieved, and targeted treatment or improvement is facilitated.

Description

Technical Field

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

[0002] The power battery is an important energy supply device for electric vehicles, and its performance directly affects the endurance and safety of electric vehicles. The power battery includes a battery cell and a tab extending from the battery cell, and the tab includes a positive tab and a negative tab. A soft connector is provided on the inner side of the top cover, and a pole is provided on the outer side of the top cover. The pole is connected to the tab through the soft connector. This structural design can effectively realize the charging and discharging function of the battery cell.

[0003] The cells of dual-core power batteries are usually composed of a single or two core packs. For the cells, in the existing technology, the cells are usually combined together by welding a single soft connecting piece 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 failed 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 battery cell for targeted processing or improvement is a problem that needs to be solved urgently in the current field of power battery design. Summary of the invention

[0004] An object of the present invention is to provide a single cell 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 pole ear and a negative pole ear; each positive pole ear is correspondingly connected to a connecting plate, and the connecting plates on different positive pole ears are isolated from each other, and each negative pole ear is correspondingly connected to a connecting plate, and the connecting plates on different negative pole ears 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 with 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 pole ears are electrically connected through the terminals, and the pole assemblies corresponding to the negative pole ears are electrically connected through the terminals.

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

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

[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 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 disposed between the side wall and the peripheral side surface of the pole assembly, and / or the elastic ejector pin is elastically disposed 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, a second thread structure is provided on the terminal, and 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 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 in any one of the above items, wherein the plurality of single cells are arranged in the box body.

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

[0016] The single cell battery includes 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 a receiving cavity, and the receiving cavity has an opening communicating with the outside. 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 a positive electrode sheet, a diaphragm and a negative electrode sheet. A connecting piece is connected to the positive electrode ear of each battery cell assembly, and the connecting pieces on different positive electrode ears are isolated from each other so as not to be electrically conductive to each other. A connecting piece is connected to the negative electrode ear of each battery cell assembly, and the connecting pieces 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 piece on the positive electrode ear and the connecting piece on the negative electrode ear are also isolated from each other and do not contact each other to prevent short circuit.

[0017] The top cover is connected to the shell to cover the accommodating cavity, and the top cover is provided with a plurality of pole holes, and the pole holes include positive pole holes and negative pole holes. The plurality of pole assemblies are respectively provided with a plurality of pole holes, there are a plurality of positive pole assemblies, and the positive pole assemblies pass through the positive pole holes, there are a plurality of negative pole assemblies, and the negative pole assemblies pass through the negative pole holes, the plurality of pole assemblies are connected to a plurality of connecting pieces one by one, and the plurality of pole assemblies are isolated from each other, each positive pole assembly is connected to a connecting piece on each positive pole ear, and the positive pole assembly is electrically connected to the corresponding battery cell assembly separately, and each negative pole assembly is connected to a connecting piece on each negative pole ear separately, and the negative pole assembly is electrically connected to the corresponding battery cell assembly separately; wherein, the pole assemblies corresponding to the positive pole ears are insulated from each other, and the pole assemblies corresponding to the negative pole ears are insulated from each other.

[0018] During use, the multiple positive column assemblies and multiple negative column assemblies of the single battery are independent conductive assemblies, and the multiple positive column assemblies can be electrically conductive, and the multiple negative column assemblies can be electrically conductive. During the detection process, the positive column assembly and the negative column assembly corresponding to each battery cell assembly are connected to determine whether the performance of a single battery cell assembly is abnormal, so as to accurately locate the problem of a specific battery cell assembly in the single battery cell, so as to carry out targeted processing 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 drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. 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 creative work.

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

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

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

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

[0024] Figure 5 is a schematic diagram of a top view of a single cell provided by an embodiment of the present invention;

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

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

[0027] Figure 8 It is a schematic diagram of the structure of a connecting piece provided in an embodiment of the present invention.

[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 described embodiments 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 creative work are within the scope of protection of the present invention.

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

[0031] The embodiment of the present invention provides a single battery, which includes a shell 10, at least two battery cell assemblies 20, a plurality of connecting sheets 30, a top cover 40 and a plurality of pole assemblies 50. The shell 10 is provided with a receiving cavity 101, and the receiving cavity 101 has an opening communicating with the outside. At least two battery cell assemblies 20 are placed in the receiving cavity 101, and at least two battery cell assemblies 20 are insulated from each other. Each battery cell assembly 20 has a positive electrode ear 21 and a negative electrode ear 22. Each battery cell assembly 20 can be powered as an independent individual. The battery cell assembly 20 is formed by stacking or winding positive electrode sheets, separators, and negative electrode sheets. The positive ear 21 on each battery cell assembly 20 is connected to a corresponding connecting piece 30, and the connecting pieces 30 on different positive ears 21 are isolated from each other so as not to be electrically conductive to each other. The negative ear 22 on each battery cell assembly 20 is connected to a corresponding connecting piece 30, and the connecting pieces 30 on different negative ears 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 piece 30 on the positive ear 21 and the connecting piece 30 on the negative ear 22 are also isolated from each other and do not contact each other to prevent short circuit.

[0032] The top cover 40 is connected to the shell 10 to cover the accommodating chamber 101. The top cover 40 is provided with a plurality of pole holes 401. The pole holes 401 include positive pole holes and negative pole holes. The plurality of pole assemblies 50 are respectively provided with a plurality of pole holes 401. There are a plurality of positive pole assemblies 50, and the positive pole assemblies 50 pass through the positive pole holes. There are a plurality of negative pole assemblies 50, and the negative pole assemblies 50 pass through the negative pole holes. The plurality of pole assemblies 50 are connected one by one with the plurality of connecting pieces 30. The plurality of pole assemblies 50 are isolated from each other. Each positive pole assembly 50 is connected to the connecting piece 30 on each positive pole ear 21, and the positive pole assembly 50 is electrically connected to the corresponding battery cell assembly 20 separately. Each negative pole assembly 50 is connected to the connecting piece 30 on each negative pole ear 22, and the negative pole assembly 50 is electrically connected to the corresponding battery cell assembly 20 separately. The pole assemblies 50 corresponding to the positive pole ear 21 are insulated from each other, and the pole assemblies 50 corresponding to the negative pole ear 22 are insulated from each other.

[0033] In this embodiment, during use, the multiple positive column assemblies 50 and the multiple negative column assemblies 50 of the single battery are independent conductive assemblies, and the multiple positive column assemblies 50 can be electrically conductive, and the multiple negative column assemblies 50 can be electrically conductive. During the detection process, the positive column assembly 50 and the negative column assembly 50 corresponding to each battery cell assembly 20 are connected respectively to determine whether the performance of a single battery cell assembly 20 is abnormal, so as to accurately locate the problem of a specific battery cell assembly 20 in the single battery, so as to carry out targeted processing or improvement.

[0034] The single cell also includes a plurality of terminals 60, and the material of the terminals 60 can be copper, aluminum, iron, and alloys thereof, etc. The terminals 60 have conductive properties, and the pole assemblies 50 corresponding to the positive pole ears 21 are electrically connected through the terminals 60, and the pole assemblies 50 corresponding to the negative pole ears 22 are electrically connected through the terminals 60. A part of the terminals 60 connects the pole assemblies 50 corresponding to the positive pole ears 21 in parallel, and another part of the terminals 60 connects the pole assemblies 50 corresponding to the positive pole ears 21 in parallel. In the production process of the single cell, multiple positive pole assemblies 50 and multiple negative pole assemblies 50 are electrically conductive in advance through the terminals 60, so that in 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 use 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 power-on 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. The detachable connection specifically means that the terminal 60 and the pole assembly 50 can be detached by hand, so as to facilitate the quick removal from the pole assembly 50 during the subsequent single cell fault detection. The detachable connection methods include snap connection, threaded connection, bonding, and interference fit.

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

[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 a square structure, the terminal 60 can be rotated at multiples of 90 degrees; when the terminal 60 is a circular structure, the terminal 60 can be rotated at any angle until it cannot be rotated. During assembly or disassembly, it is only necessary to rotate the terminal 60 without losing the connection structure between the terminal 60 and the pole assembly 50. In addition, during the rotation process, the preload force between the terminal 60 and the pole assembly 50 can be adjusted to ensure a stable electrical conduction relationship 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 column assemblies 50 also form a circular structure, and the plurality of negative electrode column assemblies 50 also form a circular structure, so that the terminal 60 can be easily rotated relative to the positive electrode column assembly 50 and the negative electrode column 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 around 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 interference fit with the limiting groove 601.

[0041] See also Figure 6 and Figure 7 As shown, Figure 6 is a cross-sectional schematic diagram of another embodiment of a single cell provided by an embodiment of the present invention, Figure 7 The embodiment of the present invention 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, and 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, and the terminal 60 is similar to a hat-like structure. The side wall 63 is connected to the peripheral side of the pole assembly 50, and 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 to prevent poor contact.

[0043] Furthermore, the single cell also includes a conductive paste, which is arranged in the limiting groove 601. Electric composite grease, also known as conductive paste, is a neutral conductive dressing with good electrical contact performance. It is suitable for the contact surface of the high and low voltage electrical busbar overlap and various electrical joints, which can significantly reduce the contact resistance, thereby obtaining good power saving economic benefits. The conductive paste is filled in the limiting groove 601, the conductive end of the pole assembly 50 is assembled in the limiting groove 601, and the conductive paste is filled in the small gap between the conductive end and the limiting groove 601, which can not only reduce the conduction resistance between the two, but also improve the conduction efficiency and avoid the waste of electric energy.

[0044] Further, 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 pole assembly 50, and / or, the elastic ejector pin 70 is elastically disposed between the top wall 61 and the conductive end of the pole assembly 50. This embodiment includes three cases, 1: the elastic ejector pin 70 is elastically disposed between the side wall 63 and the peripheral side surface of the pole assembly 50; 2: the elastic ejector pin 70 is elastically disposed between the top wall 61 and the conductive end of the pole assembly 50; 3: the elastic ejector pin 70 is elastically disposed between the side wall 63 and the peripheral side surface of the pole assembly 50, and the elastic ejector pin 70 is elastically disposed between the top wall 61 and the conductive end of the pole assembly 50.

[0045] The elastic ejector pin 70 is elastic and can retract to store elastic force when subjected to external force. After the external force disappears, the elastic ejector pin 70 can restore its deformation by the elastic force. 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 elastic ejector pin 70 can not only ensure the detachable connection between the terminal 60 and the pole assembly 50 through the static friction force of the contact between the two, but also when the terminal 60 shakes left and right, the elastic ejector pin 70 can still be held on the terminal 60 by elastic force, 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 conduction efficiency.

[0048] See also Figure 1 , Figure 2 and Figure 8 As shown, Figure 8 Schematic diagram of the structure of the connecting piece 30 provided in an embodiment of the present invention.

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

[0050] Specifically, the connecting piece 30 includes a connecting end 31 and a transition end 33 that are connected to each other, the surface area of ​​the connecting end 31 is larger than the surface area of ​​the transition end 33, the connecting end 31 is connected to the positive pole ear 21 or the negative pole ear 22, and the transition end 33 is connected to the pole assembly 50. The surface area of ​​the connecting end 31 is larger than that of the transition end 33, so that the connecting piece 30 has a large enough area to connect to the positive pole ear 21 or the negative pole ear 22, thereby ensuring normal electrical conduction, and reducing resistance and heat generation at the connecting end 31.

[0051] The present application also protects a battery pack, which includes a box and multiple single cells as 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 connection of series and parallel.

[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, movement status, etc. between the 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 on" or "disposed on" another element, it may be directly on the other element or there may be an intermediate element at the same time. When an element is referred to as being "connected to" another element, it may be directly connected to the other element or may be indirectly connected to the other element through an intermediate element.

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

[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 changes made by using the contents of the present invention specification and drawings under the inventive concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A single cell battery, characterized in that: include: A 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 ear and a negative electrode ear; A plurality of connecting pieces, each of the positive electrode ears is connected to a corresponding connecting piece, and the connecting pieces on different positive electrode ears are isolated from each other; each of the negative electrode ears is connected to a corresponding connecting piece, and the connecting pieces on different negative electrode ears 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 sheets 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 cell further includes a plurality of terminals, through which the pole assemblies corresponding to the positive pole lugs are electrically connected, and through which the pole assemblies corresponding to the negative pole lugs 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 groove, and the conductive end of the pole assembly is assembled in the limiting groove.

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 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 cell further includes a conductive paste, and the conductive paste is disposed in the limiting groove.

7. The single cell according to claim 5, characterized in that: The single battery cell further comprises 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 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 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 that are 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 comprises: a box body and a plurality of single cells according to any one of claims 1 to 9, wherein the plurality of single cells are arranged in the box body.

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