Single battery and battery pack

Abstract

The utility model discloses a single battery and a battery pack. The single battery comprises a cover body assembly, and the cover body assembly comprises a top cover and a pole; the battery cell assembly comprises a main body and a tab bundle; the plate is matched with the pole to clamp the tab bundle, and the plate, the tab bundle and the pole are welded and fixed; the plate piece is also connected with the pole column through the connecting piece; wherein the connecting piece is positioned outside the tab bundle. The plate and the pole are connected through welding and are also fixedly connected through the connecting piece outside the tab area, so that the connection is more reliable and stable. The plate is fixedly connected to the pole through the connecting piece, so that the connecting piece can be used as reference positioning when the tab bundle is placed, the placement positions of tabs of different battery cells tend to be consistent when the tabs are welded, the positions of the plate pressed on the tab bundle can be adjusted to be consistent more easily, and finally, the consistency of the welding positions is ensured; and the welding quality of the battery cell group is improved.

Description

Technical Field

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

[0002] In the battery production process, the connection structure between the tab and the pole is a key structure, which affects the current flow effect and reliability between the battery cell and the pole. The tab and the pole are usually connected by welding to achieve fixation and electrical conduction.

[0003] In the current related technology, a pressure plate is set on the side of the pole ear away from the pole, and an external mechanism is used to apply pressure to the pressure plate toward the pole before welding, so that the pressure plate squeezes the pole ear so that the multiple layers of pole ears fit tightly together, thereby facilitating welding.

[0004] However, the current pressure plate is only connected to the pole by welding, and its reliability is not sufficient. For example, in some usage scenarios with more vibration conditions, the connection between the pressure plate and the pole is not strong enough. In addition, it is difficult to ensure that the position of the pole ear on the pole is the same when processing different single cells, and it is also difficult to ensure that the position where the pressure plate is crimped to the pole ear is the same, which ultimately leads to insufficient consistency among different single cells. Utility Model Content

[0005] The present application provides a single cell and a battery pack to solve the current technical problems of unreliable connection between the pressure plate and the pole and poor welding consistency.

[0006] In a first aspect, the present application provides a single cell, comprising:

[0007] A cover assembly, the cover assembly comprising a top cover and a pole;

[0008] A battery cell assembly, the battery cell assembly comprising a main body and a tab bundle;

[0009] A plate, which cooperates with the pole to clamp the pole lug bundle, and the plate, the pole lug bundle and the pole are welded and fixed;

[0010] A connecting piece, through which the plate and the pole are also connected;

[0011] Wherein, the connecting piece is located outside the tab bundle.

[0012] To implement the above technical solution, first, in addition to forming a connection relationship between the plate and the pole by welding, the plate and the pole can also be fixedly connected by a connector outside the pole ear area, that is, there are two ways of fixing the plate and the pole, and the connection is more reliable and stable, and the reliability of the connection between each component can be maintained even in frequent bumpy conditions. Second, since the plate has been fixedly connected to the pole by the connector, the connector can be used as a reference for positioning the pole ear, ensuring that the positions of the pole ears of different battery cells tend to be consistent when welding, and the position of the plate crimped on the pole ear is also easier to adjust to be consistent, ultimately ensuring the consistency of the welding position and improving the welding quality of the battery cell.

[0013] As one of the optional embodiments of this solution, the pole has a connecting surface, the pole tab bundle is fixedly connected to the connecting surface, the connecting piece is arranged at the edge of the connecting surface, and the edge of the pole tab bundle abuts against the connecting piece.

[0014] To implement the above technical solution, the connector is arranged at the edge of the connecting surface to ensure that there is enough space on the connecting surface for the tab bundle to be placed, and the edge of the tab bundle abuts the connector so that the tab bundle can be accurately positioned by relying on the position of the connector to ensure the consistency of the welding position of the tab bundles in different single cells on the connecting surface, so as to improve the performance during subsequent assembly into products such as battery packs.

[0015] As one of the optional embodiments of this solution, the plate has a contact surface facing the connection surface and in contact with the tab bundle, and the distance between the contact surface and the connection surface is h;

[0016] Along the direction perpendicular to the connection surface, the thickness of the tab bundle outside the plate crimping area is H mm, satisfying: h <H。

[0017] To implement the above technical solution, the plate can squeeze the tab bundle during welding, which can constrain the tab bundle more tightly to avoid loosening of the tab bundle, reduce the welding thickness of the tab bundle, reduce welding difficulty, and improve welding quality.

[0018] As one of the optional embodiments of this solution, the single battery further includes a bridge member, the bridge member passes through the tab bundle in a direction perpendicular to the connection surface, and the bridge member is respectively connected to the connection surface and the contact surface.

[0019] As one of the optional embodiments of the present solution, there is a gap between two adjacent bridging members, and the distribution density of the bridging members gradually decreases from the center to the edge of the connecting surface.

[0020] As one of the optional embodiments of this solution, the connecting member is arranged on the edge of the pole.

[0021] As one of the optional embodiments of this solution, the connecting member includes:

[0022] A base portion, fixedly connected to the pole;

[0023] A rotating shaft portion, arranged on the base portion and / or the plate, wherein the rotating axis of the rotating shaft portion is parallel to the connecting surface;

[0024] The plate is connected to the base portion through the rotating shaft portion.

[0025] As one of the optional embodiments of this solution, the connecting member includes a flexible plate, and the flexible plate is connected to the plate member and the pole respectively.

[0026] As one of the optional embodiments of this solution, the connecting member includes:

[0027] A fixing part, fixedly connected to the pole;

[0028] A shaft body portion, arranged on the fixing portion and / or the plate, wherein the axis of the shaft body portion is perpendicular to the connecting surface;

[0029] The plate is connected to the shaft body.

[0030] On the other hand, the present application also proposes a battery pack, which includes:

[0031] Box;

[0032] The above-mentioned single cell.

[0033] The above technical solution has the following advantages or beneficial effects:

[0034] In addition to forming a connection relationship between the plate and the pole by welding, the plate and the pole can also be fixedly connected by connecting parts outside the pole ear area, that is, there are two ways of fixing the plate and the pole, and the connection is more reliable and stable, and the reliability of the connection between the various components can be maintained even under frequent bumpy conditions; and because the plate is fixedly connected to the pole by connecting parts, the connecting parts can be used as a reference for positioning the pole ears when placing them, ensuring that the positions of the pole ears of different battery cells tend to be consistent when welding, and the position where the plate is crimped on the pole ears is also easier to adjust to be consistent, ultimately ensuring the consistency of the welding position, improving the welding quality of the battery cell group and the reliability of the battery cell structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The technical solution and other beneficial effects of the present application will be made apparent by describing in detail the specific implementation methods of the present application in conjunction with the accompanying drawings.

[0036] Figure 1 This is a structural schematic diagram of the process of placing the pole ear on the pole provided in Example 1 of the present application;

[0037] Figure 2 This is provided in Example 1 of the present application Figure 2 A partial enlarged view of the

[0038] Figure 3 It is a schematic diagram provided in Example 1 of the present application and mainly used to represent the structure of the connecting piece;

[0039] Figure 4 It is an exploded structural diagram provided in Example 1 of the present application and mainly used to represent the structure of the connector;

[0040] Figure 5 is a cross-sectional view of the plate from the pressed state to the welded state provided in Example 1 of the present application;

[0041] Figure 6 It is a schematic diagram provided in Example 1 of the present application and mainly used to show the structure of the bridge member;

[0042] Figure 7 is a cross-sectional view of a bridge member provided in Example 1 of the present application when the bridge member is in a spike shape;

[0043] Figure 8 is a schematic diagram of another connecting member structure provided in Example 2 of the present application;

[0044] Fig. 9 is a cross-sectional view of another connecting member structure provided in Example 3 of the present application;

[0045] Fig.10 yes Fig. 9 Top view of .

[0046] Reference numerals: 1, cover assembly; 11, top cover; 12, pole; 121, connection surface;

[0047] 2. Battery cell assembly; 21. Main body; 22. Tab bundle;

[0048] 3. Plate; 31. Contact surface;

[0049] 4, connecting member; 41, base portion; 42, rotating shaft portion; 421, side shaft; 422, intermediate shaft; 4n, flexible plate; 4a, fixing portion; 4a1, fixing hole; 4b, shaft portion; 4b1, main shaft; 4b2, limit block;

[0050] 5. Bridging parts. DETAILED DESCRIPTION

[0051] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0052] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the term "and / or" in this article is only a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article, unless otherwise specified, generally indicates that the associated objects before and after are in an "or" relationship.

[0053] The following is combined with Figure 1-9 The present application is further described.

[0054] Example 1

[0055] Reference Figure 1 and Figure 2 The present application provides a single cell battery, which includes a cover assembly 1 and a cell assembly 2. The cover assembly 1 includes a top cover 11 and a pole 12 arranged on the top cover 11, the top cover 11 is rectangular, the pole 12 passes through the top cover 11 along the thickness direction of the top cover 11 and partially exposes the pole 12, and the pole 12 is fixedly connected to the top cover 11. There are two cell assemblies 2, each of which includes a main body 21 and a tab bundle 22, wherein the main body 21 is formed by stacking or winding a positive electrode sheet, a negative electrode sheet and a diaphragm, and the tab bundle 22 is formed by stacking a plurality of single-layer tabs. The pole 12 has a connecting surface 121 for achieving electrical connection with the tab bundle 22.

[0056] Reference Figure 2 and Figure 3 The single cell also includes a plate 3 and a connector 4. Before the tab bundle 22 is welded to the pole 12, the tab bundle 22 is placed on the connection surface 121, and the connector 4 is located outside the tab bundle 22 and at the edge of the pole 12. In this embodiment, the plate 3 is a flat metal plate, and the plate 3 is connected to the pole 12 through the connector 4. Before welding, the plate 3 covers the surface of the tab bundle 22 facing away from the connection surface 121, and cooperates with the pole 12 to clamp the tab bundle 22, and then the plate 3, the tab bundle 22 and the pole 12 are fixed by welding. In this embodiment, the welding process can be at least one of laser welding, resistance welding or ultrasonic welding.

[0057] Before welding, since the plate 3 has been fixedly connected to the pole 12 through the connector 4, the connector 4 can be used as a reference positioning point when placing the pole lug bundle 22, ensuring that the positions of the pole lug bundles 22 of different battery cells are placed in a consistent manner during welding, and the placement of each pole lug in the pole lug bundle 22 is relatively neat, and the position of the plate 3 crimped on the pole lug bundle 22 is also easier to adjust to be consistent, ultimately ensuring the consistency of the welding position and reducing the possibility of cold solder joints due to the uneven placement of the pole lug bundle 22.

[0058] Reference Figure 3 and Figure 4 , the center line between the two pole lug bundles 22 is defined as the first direction, and the specific structure of the connector 4 in this embodiment is disclosed below. The connector 4 includes a base portion 41, which is fixedly connected to the pole 12, and the base portion 41 is set to a rectangular block. The base portion 41 is fixedly connected to the vertical surface of the pole 12 on either side of the first direction; and a shaft portion 42, the shaft portion 42 includes a side shaft 421 arranged on the plate 3 along the first direction and an intermediate shaft 422 fixedly arranged between the two side shafts 421, the intermediate shaft 422 is coaxially arranged with the side shaft 421, and the diameter of the intermediate shaft 422 is smaller than the side shaft 421. After assembly, the intermediate shaft 422 passes through the base portion 41 along the first direction and is rotatably connected to the base portion 41, so that the plate 3 can be movably connected to the pole 12 before welding. In other optional embodiments, the shaft portion 42 can also be arranged on the plate 3. Since the rotation axis of the rotation shaft portion 42 is parallel to the connection surface 121 , the plate 3 can rotate around the axis of the rotation shaft portion 42 to approach or move away from the connection surface 121 before welding.

[0059] Reference Figure 3 , Figure 4 and Figure 5, the top of the base portion 41 protrudes upward compared to the connecting surface 121, that is, in this figure, the rotation axis of the shaft portion 42 is higher than the height of the plane where the connecting surface 121 is located, that is, the rotation axis and the main body of the pole 12 are arranged on the opposite side of the connecting surface 121. This setting is to enable the plate 3 to be movably connected to the pole 12 through the connecting member 4 and to form a first state and a second state before the plate 3, the pole lug bundle 22 and the pole 12 are welded and fixed, so as to prevent the pole lug bundle 22 from interfering with the plate 3 when switching between the first state and the second state when it is placed on the connecting surface 121. In the first state, the orthographic projection of the plate 3 on the plane where the connection surface 121 is located is at least partially located outside the orthographic projection area of ​​the tab bundle 22 on the connection surface 121. This setting is to avoid the plate 3 interfering with the process of the tab bundle 22 being placed on the connection surface 121, and to ensure that the tab bundle 22 can be placed on the connection surface 121 more conveniently; in the second state, the plate 3 contacts the side of the tab bundle 22 away from the connection surface 121, that is, the orthographic projection of the plate 3 on the plane where the connection surface 121 is located falls within the area surrounded by the connection surface 121. At this time, it is necessary to ensure that the plate 3 is parallel to the connection surface 121, so the base part 41 adopts the above structural setting. After welding, the plate 3, the tab bundle 122 and the pole 12 are welded and fixed together, and the edge of the tab bundle 22 abuts the connector 4, and the plate 3 cannot move at this time. The tab bundle 22 is positioned by the position of the connector 4 to ensure that the welding positions of the tab bundles 22 in multiple single cells on the connection surface 121 are consistent, thereby ensuring the performance of the single cells, battery groups or battery packs.

[0060] As mentioned above, due to the presence of the connector 4, firstly, since the plate 3 has been fixedly connected to the pole 12 through the connector 4, the connector 4 can be used as a reference for positioning the pole lugs, ensuring that the positions of the pole lug bundles 22 of different cells are placed in a consistent manner during welding, and the position where the plate 3 is crimped on the pole lug bundles 22 is also easier to adjust to be consistent, ultimately ensuring the consistency of the welding position and improving the welding quality of the cell group. Secondly, in addition to forming a connection relationship between the plate 3 and the pole 12 through welding, the plate 3 can also be fixedly connected through the connector 4 outside the pole lug bundle 22 area, that is, there are two ways of fixing between the plate 3 and the pole 12, and the connection is more reliable and stable, and the reliability of the connection of each component can be maintained even in frequent bumpy working conditions.

[0061] Reference Figure 5 and Figure 6, the plate member 3 has a contact surface 31 facing the connection surface 121 and contacting the tab bundle 22, and the distance between the contact surface 31 and the connection surface 121 is h; along the direction perpendicular to the connection surface 121, the thickness of the tab bundle 22 outside the crimping area of the plate member 3 is H, satisfying: h < H. This setting indicates that the plate member 3 squeezes the tab bundle 22 during welding, which can constrain the tab bundle 22 more tightly to avoid loosening of the tab bundle 22, and reduce the thickness of the tab bundle 22 during welding, reduce the welding difficulty, and improve the welding quality.

[0062] Referring to Figure 5 and Figure 6 , the single cell further includes a bridging member 5. Before the plate member 3 is welded to the tab bundle 22, the bridging member 5 is a part protruding from the contact surface 31. In this embodiment, the bridging member 5 is spherical before welding, and the bridging member 5 presses against the side surface of the tab bundle 22 facing away from the connection surface 121 before welding. During resistance welding, the presence of the bridging member 5 increases the pressure and current density on the joint surface, which is conducive to the rupture of the joint surface and heat concentration, so as to facilitate the rapid formation of the fusion nucleus. After welding is completed, the bridging member 5 passes through the tab bundle 22 along the direction perpendicular to the connection surface 121, and the bridging member 5 is respectively connected to the connection surface 121 and the contact surface 31, thereby realizing the fixation of the connection surface 121 and the contact surface 31 through the bridging member 5. In other alternative embodiments, the bridging member 5 may also protrude from the connection surface 121, or protrude from both the connection surface 121 and the contact surface 31 to form the bridging member 5.

[0063] Referring to Figure 7 , in other alternative embodiments, the tab bundle 22 is made of a composite material, that is, each layer of tab includes a base material layer and metal layers laminated on opposite surfaces of the base material layer. The base material layer is a polymer material. In the tab bundle 22 composed of multiple tabs made of the composite material, the middle is isolated by a polymer material layer. At this time, it is difficult to perform resistance welding. Therefore, a bridging member 5 protrudes from at least one of the connection surface 121 and the contact surface 31, and the end of the bridging member 5 is set to be spiky, so that when an external pressure is applied to the plate member 3 towards the connection surface 121 before welding, the bridging member 5 can penetrate the tab bundle 22 and finally contact the connection surface 121, which is conducive to the smooth progress of resistance welding. When welding is completed, the bridging member 5 penetrates the tab bundle 22, thereby improving the overcurrent capacity. In some embodiments, the number of the bridging members 5 is multiple, and there is a gap between two adjacent bridging members 5. The distribution density of the bridging members 5 gradually decreases from the center to the edge of the connection surface 121 to improve the connection strength at the center.

[0064] Based on the above single cell, multiple single cells can be combined into a battery module by series connection or parallel connection, and then the battery module is installed in a box and a battery management system is installed to obtain a battery pack.

[0065] Embodiment 2

[0066] Reference Figure 8 , which is different from Example 1, is that the connector 4 includes a flexible plate 4n, which is fixedly connected to the plate 3 and the pole 12 respectively to realize the switching of the plate 3 between the first state and the second state. The flexible plate 4n is also fixedly connected to a vertical side of the pole 12 at one end, and the flexible plate 4n can be made of a bendable thin copper sheet, aluminum sheet, etc. A bendable sheet made of other non-metallic materials can also be used. This embodiment discloses another specific structure of the connector 4, which can make the plate 3 movably connected to the pole 12 by relying on its own deformation.

[0067] Example 3

[0068] Reference Fig. 9 and Fig.10 , which is different from Example 1, is that the connecting member 4 includes a fixing portion 4a, which is fixedly connected to the pole 12, and the fixing portion 4a is arranged in a columnar shape. A fixing hole 4a1 is coaxially provided on the fixing portion 4a along the vertical direction, and the axis of the fixing hole 4a1 is perpendicular to the connecting surface 121. It also includes a shaft body portion 4b, and the shaft body portion 4b includes a main shaft 4b1 and a stop block 4b2 arranged at the bottom of the main shaft 4b1. The main shaft 4b1 vertically penetrates the fixing hole 4a1 so that the main shaft 4b1 can rotate in the fixing hole 4a1, and the stop block 4b2 prevents the main shaft 4b1 from being separated from the fixing hole 4a1. Before the plate 3 is fixedly connected to the pole lug bundle 22, the plate 3 is rotatably arranged on the fixing portion 4a through the shaft body portion 4b to realize the switching of the plate 3 between the first state and the second state. In some embodiments, the main shaft 4b1 and the stop block 4b2 are two parts arranged separately, and in some embodiments, the main shaft 4b1 and the stop block 4b2 are integrally formed.

[0069] In some optional embodiments, the fixing portion 4 a may be formed integrally with the pole 12 , that is, the fixing hole 4 a 1 may be formed on the pole 12 .

[0070] The above description is only a partial implementation method of the embodiments of the present application and does not constitute any form of limitation on the application. The protection scope of the embodiments of the present application is not limited thereto. Any simple modifications, equivalent changes and modifications that can be easily thought of by any technician familiar with the technical field within the technical scope disclosed in the embodiments of the present application should be covered within the protection scope of the embodiments of the present application.

Claims

1. A single cell battery, characterized in that: include: A cover assembly (1), the cover assembly (1) comprising a top cover (11) and a pole (12); A battery cell assembly (2), the battery cell assembly (2) comprising a main body (21) and a tab bundle (22); A plate (3) is arranged to cooperate with the pole (12) to clamp the pole lug bundle (22), and the plate (3), the pole lug bundle (22) and the pole (12) are welded and fixed; A connecting member (4), wherein the plate member (3) and the pole (12) are also connected via the connecting member (4); Wherein, the connecting piece (4) is located outside the tab bundle (22).

2. The single cell according to claim 1, characterized in that: The pole (12) has a connection surface (121), the pole lug bundle (22) is fixedly connected to the connection surface (121), the connecting piece (4) is arranged at the edge of the connection surface (121), and the edge of the pole lug bundle (22) abuts against the connecting piece (4).

3. The single cell according to claim 2, characterized in that: The plate (3) has a contact surface (31) facing the connection surface (121) and in contact with the tab bundle (22), and the distance between the contact surface (31) and the connection surface (121) is hmm; Along the direction perpendicular to the connection surface (121), the thickness of the tab bundle (22) outside the crimping area of ​​the plate (3) is H mm, satisfying: <H。 4. The single cell according to claim 3, characterized in that: The single cell further comprises a bridge member (5), the bridge member (5) passing through the tab bundle (22) in a direction perpendicular to the connection surface (121), and the bridge member (5) is respectively connected to the connection surface (121) and the contact surface (31).

5. The single cell according to claim 4, characterized in that: There is a gap between two adjacent bridge members (5), and the distribution density of the bridge members (5) gradually decreases from the center to the edge of the connecting surface (121).

6. The single cell according to claim 1, characterized in that: The connecting piece (4) is arranged on the edge of the pole (12).

7. The single cell according to any one of claims 2 to 5, characterized in that: The connecting member (4) comprises: A base portion (41) fixedly connected to the pole (12); A rotating shaft portion (42) is arranged on the base portion (41) and / or the plate (3), and a rotation axis of the rotating shaft portion (42) is parallel to the connecting surface (121); The plate (3) is connected to the base portion (41) via the rotating shaft portion (42).

8. The single cell according to any one of claims 2 to 6, characterized in that: The connecting member (4) comprises a flexible plate (4n), and the flexible plate (4n) is respectively connected to the plate member (3) and the pole (12).

9. The single cell according to any one of claims 2 to 5, characterized in that: The connecting member (4) comprises: A fixing portion (4a) fixedly connected to the pole (12); An axial body portion (4b) is arranged on the fixing portion (4a) and / or the plate (3), and an axis of the axial body portion (4b) is perpendicular to the connecting surface (121); The plate (3) is connected to the shaft portion (4b).

10. A battery pack, characterized in that: include: Box; A single cell as claimed in any one of claims 1 to 9.

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