A novel grouping structure for large cylindrical battery cells

Abstract

The present invention discloses a novel grouping structure for large cylindrical battery cells, comprising a battery cell group composed of a number of battery cells and upper and lower brackets at both ends thereof; a number of mutually cooperating filling columns and glue filling columns are respectively provided in the middle parts of the upper and lower brackets; a gasket for interfering with the circumferential movement of the battery cells is provided on the filling column; a glue filling hole cooperating with the filling column is provided in the center of the glue filling column; glue is provided in the glue filling hole; busbars are provided at both ends of the battery cell group; a heat conducting pad, a heating film and a heat preservation pad are sequentially provided on the outer side of the busbar. The present invention provides a novel grouping structure for large cylindrical battery cells, which can improve the anti-tearing ability of the aluminum pole ear welding of large cylindrical battery cells, balance the heating area of a single battery cell and ensure the heating consistency.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium batteries, and particularly to a new grouping structure for large cylindrical battery cells. Background Art

[0002] With the progress and development of society, the intelligence in aspects such as warehousing, household, and travel, and the diversification of portable consumer electronics products, the battery, as a provider of clean energy, has been increasingly pursued and favored by consumers and has become an indispensable part of electronic products.

[0003] In the application process, by improving the reliability and safety of the battery pack and enhancing the temperature environment of the battery pack to adapt to harsh environments, it is helpful to improve user satisfaction and has become a very meaningful research topic.

[0004] In the prior art, taking the 18650 battery cell as an example, the radial dimensions of cylindrical battery cells are relatively concentrated and stable. For cylindrical battery cells with an ultra-large diameter, the diameter range is large, and the tab is made of aluminum. The connection between the tab and the connecting piece usually uses laser welding, but the welding bonding force of aluminum alloy is weak. Affected by vibration, the diameter range of the bracket is large, resulting in a large clearance fit with the bracket. Therefore, during vibration, there is a risk of tearing of the tab welding, that is, the power supply circuit fails. Secondly, in order to make the battery pack adapt to the harsh low-temperature environment in winter and heat the battery pack, the battery pack is usually heated by winding the surface of the battery cell to achieve heating of the battery cell. However, this winding method cannot control the effective contact area of the battery cell, so the heating of each battery cell is uneven. As a result, the discharge internal resistance of each battery cell is inconsistent due to temperature reasons, so the battery cells generate mutual power compensation and other situations. In the long run, the battery cells enter the aging period in advance, and the driving mileage is lower than the expected life value, bringing a bad experience to users. Summary of the Invention

[0005] The purpose of the present invention is to overcome the above-mentioned deficiencies in the prior art and provide a new grouping structure for large cylindrical battery cells that improves the anti-tearing ability of aluminum tab welding of large cylindrical battery cells, balances the heating area of single battery cells, and ensures consistent temperature rise.

[0006] The present invention is realized in the following way:

[0007] A new grouping structure for large cylindrical battery cells, comprising a battery cell group composed of a number of battery cells 1 and upper brackets 2 and lower brackets 3 at both ends thereof; several mutually cooperating filling columns 21 and potting columns 31 are respectively provided in the middle parts of the upper bracket 2 and the lower bracket 3; a gasket 4 interfering with the side wall of the circumferential battery cell 1 is provided on the filling column 21; a potting hole 311 cooperating with the filling column 21 is provided in the center of the potting column 31; glue is provided in the potting hole 311; busbars 71 are provided at both ends of the battery cell group; a heat-conducting pad 72, a heating film 73, and a heat-insulating pad 74 are sequentially provided outside the busbar 71.

[0008] Further, several overflow grooves 312 communicating with the potting hole 311 are provided along the length direction at the upper end part of the potting column 31.

[0009] Further, an adhesive part 313 connected to the side walls of several circumferential battery cells through the glue overflowing from the overflow groove 312 is provided on the outer side wall of the potting column 31 along the length direction.

[0010] Further, the glue is a structural adhesive.

[0011] Further, the length of the filling column 21 is greater than the depth of the potting hole 311.

[0012] Further, the gasket 4 is circular; the interference amount between the edge of the gasket 4 and the side wall of the battery cell is 1 - 1.5 mm.

[0013] Further, the upper bracket 2 and the lower bracket 3 are locked and fixed through a number of screws 51 and nuts 52 uniformly arranged in the middle and passing through the battery cell group.

[0014] Further, a back glue gasket 6 opposite to the adhesive part 313 is provided at the joint on the side of the upper bracket 2 and the lower bracket 3.

[0015] Further, a protection board 8 is connected to the outermost side of the battery cell group.

[0016] Further, a flexible connection is made between the busbar 71 and the rigid heating film 73 through an elastic heat-conducting pad 72.

[0017] The beneficial effects of the present invention are as follows: 1. The colloid is filled and overflowed onto the surface of the battery cell housing and the bracket, and the battery cells are bonded and fixed through the overflowing colloid. And the interference between the gasket and the battery cells eliminates or weakens the problem that it is not easy to fix due to the large tolerance of the diameter of the battery cells; the stability of the battery cell fixation is improved and a reasonable distance between each battery cell is ensured, which is convenient for the temperature balance during heating.

[0018] 2. Each battery cell has a definite heating area, so that the temperature rise of the battery cells is consistent, that is, the internal resistance is close. Promote the life of the battery cells after grouping to be close to the life of the single battery cell;

[0019] 3. An explosion-proof valve is provided on the end face of the bracket corresponding to the battery cell, which provides a pressure relief channel in extreme situations and extends the valuable escape time for users in the extreme state of the battery cell. Description of the Drawings

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

[0021] Figure 1 Explosion diagram of the structure of the present invention;

[0022] Figure 2 Schematic diagram of the lower bracket structure of the present invention;

[0023] Figure 3 Partial cross-sectional view of the battery pack of the present invention;

[0024] Figure 4 Longitudinal cross-sectional view of the battery pack of the present invention;

[0025] Figure 5 Assembly schematic diagram of the battery pack of the present invention. Detailed Embodiments

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

[0027] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "upper", "lower", "inner", "outer", "front end", "rear end", "both ends", "one end", "the other end", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0028] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "installed", "provided with", "connected", etc. should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0029] Embodiment:

[0030] As Figures 1-5 shown, a new type of grouping structure for large cylindrical battery cells includes a battery cell group composed of several battery cells 1 and upper brackets 2 and lower brackets 3 at both ends thereof; several mutually cooperating filling columns 21 and potting columns 31 are respectively provided in the middle parts of the upper brackets 2 and the lower brackets 3; a gasket 4 that interferes with the circumferential side wall of the battery cell 1 is provided on the filling column 21; a potting hole 311 that cooperates with the filling column 21 is provided in the center of the potting column 31; glue is provided in the potting hole 311; busbars 71 are provided at both ends of the battery cell group; a heat-conducting pad 72, a heating film 73, and a heat-insulating pad 74 are sequentially provided outside the busbars 71.

[0031] In an embodiment of the present invention, several overflow grooves 312 communicating with the potting hole 311 are provided along the length direction at the upper end of the potting column 31; an adhesive part 313 connected to the circumferential side walls of several battery cells through the glue overflowing from the overflow grooves 312 is provided on the outer side wall of the potting column 31 along the length direction; the glue is a structural glue; when the overflow grooves 312 are working, the overflow glue in the potting hole 311 can be introduced between the adhesive part 313 and the side wall of the battery cell, and at the same time, it plays a role in fixing the battery cell. The glue is used to fix the upper and lower brackets on the one hand, and the overflow glue also fixes the brackets and the battery cell brackets. The cost is low and the fixing effect is good. Since the adhesive part 313 is in direct contact with the surface of the battery cell through the overflow glue, the heat of the battery cell can be conducted to the bracket for heat dissipation.

[0032] In one embodiment of the present invention, the length of the filling column 21 is greater than the depth of the potting hole 311. With this setting, it is ensured that the filling column 21 can completely extend to the bottom of the potting hole 311, and at the same time, a certain movement space can be left for the gasket 4, so that although the gasket 4 is in interference fit with the battery cell, it is not completely a rigid connection. When the battery cell vibrates or is impacted, the gasket 4 can obtain a certain movement space along the length direction of the battery cell, avoiding the surface of the battery cell being damaged by vibration in the conventional rigid connection and causing secondary damage.

[0033] In one embodiment of the present invention, the gasket 4 is circular; the interference amount between the edge of the gasket 4 and the side wall of the battery cell is 1-1.5 mm. Here, the interference amount is the interference fit amount. Fixing the middle part of the battery cell in this way of interference fit has better stability and safety. On the one hand, the mounting holes on the upper and lower brackets have a suitable clearance amount when cooperating with the battery cell, which can adapt to the deviation of the diameter of the battery cell. The battery cell is mainly fixed by the interference between the gasket 4 provided in the middle and the side wall of the battery cell, and then the auxiliary adhesive part 313, glue and the side wall of the battery cell are bonded. The fixing of the battery cell becomes the support of the middle gasket 4, the upper and lower positions are bonded by glue, and the outermost part is locked by the screw 51 and nut 52, so that the battery cell can be limited and fixed in the circumferential direction and at both ends, and at the same time, the problem that it is not easy to fix due to the large tolerance of the diameter of the battery cell is eliminated or weakened. The cooperation between the gasket 4 and the adhesive part 313 and the battery cell is equivalent to a connection and fixation of a combination of hard and soft. The gasket 4 acts as a rigid connection. Since the adhesive part 313 below the gasket 4 uses overflow glue to achieve adhesion to the battery cell, there will still be some small gaps, which makes the battery cell module have excellent shock absorption effect.

[0034] In one embodiment of the present invention, the upper bracket 2 and the lower bracket 3 are locked and fixed by a plurality of screws 51 and nuts 52 uniformly arranged in the middle and passing through the battery cell group.

[0035] In one embodiment of the present invention, a back glue gasket 6 opposite to the adhesive part 313 is provided at the joint on the side of the upper bracket 2 and the lower bracket 3. As can be seen from the above, some small gaps will be generated when the adhesive part 313 cooperates with the battery cell, so that the adhesive part 313 can have better shock absorption effect when being impacted, but at the same time, it is also the area with the largest vibration amount in the overall battery cell module. The back glue gasket 6 is used for protection here.

[0036] In one embodiment of the present invention, a protection board 8 is connected to the outermost side of the battery cell group.

[0037] In one embodiment of the present invention, a flexible connection is made between the bus bar 71 and the rigid heating film 73 through an elastic heat-conducting pad 72.

[0038] Working principle: First, the gasket 4 is sleeved on several filling columns 21 of the upper bracket 2. There are 4 filling columns 21 evenly arranged, and the gasket 4 is a circular self-adhesive gasket; further, structural adhesives are respectively poured into the four glue injection holes 311, and then the battery cell 1 is placed into the lower bracket 3. At this time, the upper bracket 2 with the gasket installed above is installed with the lower bracket 3. The edge of the gasket 4 interferes with the side walls of the 4 battery cells in the circumferential direction to prevent them from moving in the horizontal plane and effectively fix them; then the joint between the side of the upper bracket 2 and the lower bracket 3 is wrapped with a self-adhesive gasket 6; the upper bracket 2 and the lower bracket 3 are locked and fixed by 4 screws 51 and nuts 52 evenly arranged in the middle and passing through the battery cell group; then busbars 71 are respectively placed on the end faces of the upper bracket 2, and the connection is completed by laser welding. On the end face of the lower bracket 3, another busbar is placed and the connection is completed by laser welding; the heat-conducting pad 72 is pasted on the surface of the busbar 71; then the heating film 73 is pasted on the surface of the heat-conducting pad 72 and locked on the surface of the bracket with screws; the heat-insulating pad 74 is adhesively pasted on the surface of the heating film 73; then the protection board 8 is locked on the bracket with screws, the positive and negative electrodes are connected to the module through screws, and then the acquisition wire, temperature sensor wire, and heating wire are connected to the protection board 8 through connectors. This assembly is completed.

[0039] The present invention uses the colloid filling and overflowing glue to the surface of the battery case and the bracket, and the overflowing colloid flows to the bonding part 313 to bond and fix with the battery cell. And the gasket 4 interferes with the battery cell to eliminate or weaken the problem that it is not easy to fix due to the large tolerance of the battery cell diameter; improves the stability of the battery cell fixation and ensures a reasonable distance between each battery cell, facilitating the temperature balance during heating.

[0040] An overflow groove 312 and a bonding part 313 are provided on the glue injection column 31 of the lower bracket 3, and the bonding part 313 is bonded with the battery cell 1 with structural adhesive; the gap between the bonding part 313 and the battery cell is preferably 1 mm, and the filling area is preferably greater than 60 mm2 / battery cell; the tab area on the surface of the battery cell is a determined area, and it is installed on the lower bracket 3 through an aluminum row (the aluminum row is a conductive busbar), and the current is transmitted through welding with the tab. Vent holes are also provided on the aluminum row; the heat-conducting pad 72 is placed between the aluminum alloy and the heating film 73 for flexible connection. The flexible connection is to better increase the heat-conducting contact and can have a shock-absorbing function; there is 1 explosion-proof valve at the end face of the battery cell, and the explosion-proof valve is circular, preventing the battery cell from erupting when the battery cell is short-circuited. Both the bracket A and the bracket B are provided with vent holes;

[0041] Each battery cell has a definite heating area, making the temperature rise of the battery cells consistent, that is, the internal resistance is close. Promote the life of the battery cells after grouping to be close to the life of the single battery cell;

[0042] The bracket provides a pressure relief channel for the explosion-proof valve of the battery cell in the extreme situation, and extends the time for the battery cell in the extreme state, providing a valuable escape time for users.

[0043] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A new grouping structure for large cylindrical battery cells, characterized in that: It includes a battery cell group composed of a number of battery cells (1) and upper brackets (2) and lower brackets (3) at both ends thereof; several mutually cooperating filling columns (21) and potting columns (31) are respectively provided in the upper brackets (2) and the lower brackets (3); a gasket (4) that interferes with the circumferential movement of the battery cells (1) is provided on the filling column (21); a potting hole (311) that cooperates with the filling column (21) is provided in the center of the potting column (31); glue is provided in the potting hole (311); busbars (71) are provided at both ends of the battery cell group; a heat-conducting pad (72), a heating film (73), and a heat-insulating pad (74) are sequentially provided outside the busbars (71); the gasket (4) is circular; explosion-proof valves are provided on the brackets corresponding to the end faces of the battery cells.

2. The novel grouping structure of a large cylindrical battery cell according to claim 1, characterized in that: Several overflow grooves (312) communicating with the potting holes (311) are provided along the length direction at the upper end portion of the potting column (31).

3. A novel grouping structure for large cylindrical battery cells according to claim 1 or 2, characterized in that: An adhesive portion (313) that is connected to the side walls of several circumferential battery cells by the glue overflowing from the overflow grooves (312) is provided on the outer side wall of the potting column (31) along the length direction.

4. A novel grouping structure for large cylindrical battery cells according to claim 3, characterized in that: The glue is a structural adhesive.

5. A novel grouping structure for large cylindrical battery cells according to claim 3, characterized in that: The length of the filling column (21) is greater than the depth of the potting hole (311).

6. The novel grouping structure of a large cylindrical battery cell according to claim 3, characterized in that: The interference amount between the edge of the gasket (4) and the side wall of the battery cell is 1-1.5 mm.

7. The novel grouping structure of a large cylindrical battery cell according to claim 6, characterized in that: The upper brackets (2) and the lower brackets (3) are locked and fixed by a number of screws (51) and nuts (52) uniformly arranged in the middle thereof and passing through the battery cell group.

8. A novel grouping structure for a large cylindrical battery cell according to claim 7, characterized in that: A back glue gasket (6) opposite to the adhesive portion (313) is provided at the joint on the side of the upper brackets (2) and the lower brackets (3).

9. The novel grouping structure of a large cylindrical battery cell according to claim 8, characterized in that: A protection board (8) is connected to the outermost side of the battery cell group.

10. A novel grouping structure for large cylindrical battery cells according to claim 9, characterized in that: A flexible connection is made between the busbar (71) and the rigid heating film (73) through an elastic heat-conducting pad (72).

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