A secondary battery

Abstract

The utility model proposes a secondary battery, which relates to the field of batteries. The battery shell includes an outer shell and an inner shell arranged in the inner cavity of the outer shell. The inner shell has a first cavity between two opposite large surfaces and the outer shell. A plurality of elastic members are evenly arranged in the first cavity. One end of the elastic member is fixedly connected to the inner wall of the first outer shell, and the other end of the elastic member is in contact with the large surface of the inner shell. When the battery cell expands inside, the inner shell will expand. The elastic member can deform and displace in the first cavity and absorb the expansion force, so that the outer shell has no obvious expansion or deformation. In this way, the problem of displacement caused by the expansion of the battery cell can be effectively solved when the battery cell is assembled into a module, thereby reducing the pre-tightening force requirement during module assembly, reducing the risk of mutual compression between the battery cells, and improving the overall safety performance.

Description

Technical Field

[0001] The utility model relates to the technical field of power batteries, and in particular to a battery cell shell and a secondary battery for improving the internal expansion force of a battery cell. Background Art

[0002] The shell of the existing conventional power square shell battery cell is made by a stretching process. The stretched battery cell shell does not have sufficient structural strength on the large surface of the battery cell. After the core package is placed in the shell, as the battery cell ages, gas will be produced inside the battery cell. When the internal gas pressure reaches a certain level, the gas pressure inside the battery cell will compress the large surface of the battery cell and cause the large surface to swell, which brings two problems. First, the swelling of the battery cell requires that when the battery cell is processed into a module, the module needs to be grouped and fixed by setting a pre-tightening force to ensure the installation size of the module; second, when the battery cell ages, the swelling of the battery cell will increase, resulting in squeezing and deformation between the battery cells, and in extreme cases, battery cell safety problems may occur. Utility Model Content

[0003] In view of this, the utility model proposes a battery cell shell and a secondary battery that improve the internal expansion force of the battery cell, so as to solve the problem that the expansion of the battery cell during use brings potential safety hazards to module assembly and battery cell safety.

[0004] The technical solution of the utility model is achieved in this way:

[0005] On the one hand, the utility model provides a battery cell shell for improving the internal expansion force of the battery cell, the battery cell shell comprising an outer shell and an inner shell arranged in the inner cavity of the outer shell, the inner shell has a first cavity between two opposite large surfaces and the outer shell respectively, a plurality of elastic members are evenly arranged in the first cavity, one end of the elastic member is fixedly connected to the inner wall of the first outer shell, and the other end of the elastic member is abutted against the large surface of the inner shell.

[0006] Based on the above technical solution, preferably, a plurality of elastic members are evenly spaced in the first cavity along the length direction of the battery cell shell, the upper end of the elastic member is lower than the top of the inner shell, and the lower end of the elastic member abuts against the inner bottom surface of the outer shell.

[0007] As an implementation manner, the elastic member is a flat plate, and the angle between the flat plate and the large surface of the inner shell is an acute angle.

[0008] As another embodiment, the elastic member has a specific cross-sectional shape, which is a “<” shape, a ">” shape, a “C” shape, a “U” shape, or an “S” shape.

[0009] On the basis of the above technical solution, preferably, the outer wall of the outer shell corresponding to the first cavity is recessed to form at least one reinforcement portion.

[0010] On the other hand, the utility model discloses a secondary battery, which includes the battery cell shell, the top cover and the core pack accommodated in the inner shell, wherein the top cover is arranged on the top of the battery cell shell and is sealed and connected to the top of the outer shell and the inner shell respectively.

[0011] On the basis of the above technical solution, preferably, the other two opposite side surfaces of the inner shell and the outer shell respectively have a second cavity, and the second cavity is connected to the first cavity;

[0012] A plurality of limiting ribs are evenly arranged in the second cavity along the width direction of the battery shell, one end of the limiting rib in the horizontal direction is fixedly connected to the inner wall of the outer shell, and the other end of the limiting rib in the horizontal direction abuts against the outer side wall of the outer shell;

[0013] A plurality of first liquid-permeable holes are evenly arranged on the elastic member along the height direction of the battery shell, and a plurality of second liquid-permeable holes are evenly arranged on the limiting rib along the height direction of the battery shell;

[0014] The top cover is provided with a liquid inlet hole and a liquid outlet hole, and the liquid inlet hole and the liquid outlet hole are respectively communicated with the second cavities at both ends of the inner shell.

[0015] Further, preferably, there is a third cavity between the outer bottom surface of the inner shell and the inner bottom surface of the outer shell, and a plurality of support ribs are arranged at intervals in the third cavity, the length direction of the support ribs is perpendicular to the length direction of the battery cell shell, and a plurality of third liquid-permeable holes are arranged on the support ribs.

[0016] Furthermore, preferably, the support rib is also provided with at least one reinforcing rib perpendicular to the support rib.

[0017] Further, preferably, the top end of the inner shell is higher than the top end of the outer shell, and the bottom surface of the top cover is provided with a sealing groove which is sealedly connected to the top end of the outer shell.

[0018] Compared with the prior art, the utility model has the following beneficial effects:

[0019] (1) An outer shell is arranged in the inner cavity of the outer shell, and a first cavity is respectively provided between two opposite large surfaces of the inner shell and the outer shell, and a plurality of elastic members are evenly arranged in the first cavity, one end of the elastic member is fixedly connected to the inner wall of the first outer shell, and the other end of the elastic member is in contact with the large surface of the inner shell. Thus, when gas is generated inside the battery cell, the gas pressure inside the battery cell will press the large surface of the battery cell to make the large surface bulge. After the expansion force acts on the inner shell, the inner shell expands. At this time, the elastic member can deform and displace in the first cavity and absorb a part of the expansion force, so that the outer shell has no obvious expansion or deformation. In this way, the displacement problem caused by the expansion of the battery cell when the battery cell is assembled into a module can be effectively solved, thereby reducing the pre-tightening force requirement during module assembly, reducing the risk of mutual squeezing between battery cells, and improving the overall safety performance.

[0020] (2) The secondary battery disclosed in the utility model can not only limit the expansion force of the battery cell to the inside of the battery cell shell, avoiding and reducing the expansion deformation outside the battery cell shell, but also allow the coolant to be passed into the cavity between the inner shell and the outer shell, making full use of the internal structure of the battery cell shell for heat dissipation. There is no need to set a liquid cooling plate outside the battery cell, which facilitates the setting of a liquid cooling heat dissipation structure for the battery module.

[0021] (3) By providing a third cavity between the outer bottom surface of the inner shell and the inner bottom surface of the outer shell, the coolant will enter the third cavity during the flow in the first cavity and the second cavity, and flow in the third cavity through the third liquid-permeable hole, thereby dissipating heat for the bottom surface of the core package, thereby achieving heat dissipation on the five surfaces of the entire core package, greatly improving the heat dissipation efficiency of the battery cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the utility model 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 utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 It is a three-dimensional structural schematic diagram of the battery cell shell disclosed in the utility model;

[0024] Figure 2 It is a structural plane schematic diagram of a battery cell housing disclosed in the utility model;

[0025] Figure 3 It is another structural plane schematic diagram of the battery cell housing disclosed in the utility model;

[0026] Figure 4It is a three-dimensional structural schematic diagram of the secondary battery disclosed in the utility model;

[0027] Figure 5 A top view of the secondary battery disclosed in the utility model;

[0028] Figure 6 for Figure 5 Plane section view at AA in the middle;

[0029] Figure 7 for Figure 5 Plane section view at BB in the middle;

[0030] Figure 8 This is a schematic diagram of the internal structure of the outer shell disclosed in the utility model;

[0031] Fig. 9 It is a three-dimensional structural schematic diagram of the top cover disclosed in the utility model;

[0032] Reference numerals:

[0033] 1. Cell shell; 11. Outer shell; 12. Inner shell; 13. First cavity; 14. Elastic member; 111. Reinforcement; 2. Top cover; 3. Core package; 15. Second cavity; 16. Limiting ribs; 141. First liquid permeable hole; 161. Second liquid permeable hole; 21. Liquid inlet hole; 22. Liquid outlet hole; 17. Third cavity; 18. Support ribs; 181. Third liquid permeable hole; 182. Reinforcement ribs; 23. Sealing groove. DETAILED DESCRIPTION

[0034] The following will be combined with the implementation of the utility model to clearly and completely describe the technical solutions in the implementation of the utility model. Obviously, the described implementation is only a part of the implementation of the utility model, not all of the implementations. Based on the implementation of the utility model, all other implementations obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0035] like Figure 1 As shown, combined Figure 2-3 The utility model discloses a battery cell shell for improving the internal expansion force of a battery cell. The battery cell shell 1 comprises an outer shell 11 and an inner shell 12 arranged in the inner cavity of the outer shell 11. The outer shell 11 and the inner shell 12 are both square shells, wherein the inner shell 12 is used to install a square core package, and a first cavity 13 is respectively provided between two opposite large surfaces of the inner shell 12 and the outer shell 11, wherein a plurality of elastic members 14 are evenly arranged in the first cavity 13, wherein one end of the elastic member 14 is fixedly connected to the inner wall of the first outer shell 11, and the other end of the elastic member 14 is in contact with the large surface of the inner shell 12.

[0036] With the above-mentioned structural arrangement, when gas is generated inside the battery cell, the gas pressure inside the battery cell will compress the large surface of the battery cell and cause the large surface to swell. After the expansion force acts on the inner shell 12, the inner shell 12 expands. At this time, the elastic member 14 can deform and displace in the first cavity 13 and absorb part of the expansion force, so that the outer shell 11 has no obvious expansion or deformation. In this way, it can effectively solve the problem of displacement caused by the expansion of the battery cell when the battery cell is assembled into a module, thereby reducing the pre-tightening force requirement during module assembly, reducing the risk of mutual squeezing between battery cells, and improving the overall safety performance.

[0037] It should be noted that the other end of the elastic member 14 is in contact with the large surface of the inner shell 12. On the one hand, when the inner shell expands, the end of the elastic member contacting the large surface of the inner shell can be compressed, thereby achieving reliable deformation of the elastic member with low deformation resistance. On the other hand, the end of the elastic member is in contact with the large surface of the inner shell, and the two are not fixedly connected. This makes it convenient to insert the inner shell into the outer shell after the elastic member is installed inside the outer shell, thereby facilitating the assembly of the battery cell shell.

[0038] In this embodiment, a plurality of elastic members 14 are evenly spaced apart in the first cavity 13 along the length direction of the battery cell housing 1. This arrangement ensures that when the large surface of the battery cell is expanded by the internal gas in its length direction, the elastic members 14 can evenly absorb the expansion force, thereby avoiding local deformation of the battery cell housing 1 caused by concentrated expansion force.

[0039] The upper end of the elastic member 14 is lower than the top end of the inner shell 12, which prevents the elastic member 14 from contacting the bottom end of the top cover 2 when there is no expansion force, thereby reducing unnecessary contact friction and possible wear.

[0040] The lower end of the elastic member 14 is in contact with the inner bottom surface of the outer shell 11. During the assembly process of the battery shell 1 and before the inner shell 12 is installed inside the outer shell 11, the installation position of the elastic member 14 in the first cavity 13 is quickly determined by bringing the bottom end of the elastic member 14 into contact with the inner bottom surface of the outer shell 11, and then the elastic member 14 is fixedly installed inside the outer shell 11. This method provides pre-positioning for the assembly process, ensures the correct fit between the elastic member 14 and the inner shell 12, and also makes the assembly process of the entire battery cell smoother.

[0041] As an implementation method, refer to the attached Figure 2 As shown, the elastic member 14 in this embodiment is a flat plate, specifically a vertical thin aluminum sheet, and the angle between the flat plate and the large surface of the inner shell 12 is an acute angle.

[0042] With the above-mentioned structural arrangement, when the inner shell 12 expands due to the gas generated by the chemical reaction inside the battery cell, the inner shell 12 will expand outward. Since there is an acute angle between the elastic member 14 and the inner shell 12, the expansion force of the inner shell 12 will push the elastic member 14, causing it to be compressed and deformed in the first cavity 13 and displaced, absorbing the expansion force of the inner shell 12 during the displacement process, thereby avoiding or reducing the expansion force of the outer shell 11. In addition, the elastic member 14 stores energy when it is compressed. Since the battery cell is "breathing" in expansion, when the internal pressure is reduced, these elastic members 14 can return to their original shape and release the stored energy. The release of this energy helps the battery cell return to its normal shape and maintain the structural stability of the battery cell.

[0043] As an implementation method, refer to the attached Figure 3 As shown, the elastic member 14 has a specific cross-sectional shape, which is in the shape of "<", ">", "C", "U" or "S". The cross-sectional shape of the elastic member 14 designed above is consistent with the effect of the inclined flat plate, and only the structural form is different. Through its unique structural features, it is intended to effectively absorb and buffer the internal expansion force caused by the battery cell during the charging and discharging process.

[0044] As some preferred embodiments, the outer wall of the outer shell 11 corresponding to the first cavity 13 is recessed to form at least one reinforcement portion 111. Specifically, in the present embodiment, the reinforcement portion 111 is recessed on the surface of the outer shell 11, while the inner wall of the outer shell 11 is raised. Through these structural settings, the structural strength of the outer shell 11 can be improved, thereby improving the structural strength of the entire battery cell shell 1.

[0045] See attached Figure 4-9 As shown, the utility model also discloses a secondary battery, which includes a cell shell 1, a top cover 2 and a core pack 3 accommodated in an inner shell 12, wherein the top cover 2 is arranged on the top of the cell shell 1 and is sealed and connected to the top of the outer shell 11 and the top of the inner shell 12 respectively. The secondary battery disclosed in this embodiment uses a cell shell 1 with improved internal expansion force. Therefore, during the charging and discharging process of the entire secondary battery, the expansion can be limited to the inside of the cell shell 1, and the expansion deformation outside the cell shell 1 can be avoided and reduced, thereby effectively solving the problem of displacement caused by the cell expansion when the cell is assembled into modules, thereby reducing the pre-tightening force requirement during module assembly, reducing the risk of mutual compression between cells, and improving the overall safety performance.

[0046] At present, after square batteries are assembled into battery modules, the battery modules need to be equipped with a heat dissipation structure. Usually, the heat dissipation structure is to set a liquid cooling plate between the large surfaces of the square batteries. This structural setting requires adding more parts, which is troublesome to assemble and has high costs.

[0047] To this end, this embodiment further performs structural configuration based on the structure of the secondary battery described above, thereby solving the above problems.

[0048] First, the present embodiment further arranges the structure of the cell shell 1. Specifically, the other two opposite sides of the inner shell 12 and the outer shell 11 respectively have a second cavity 15, and the second cavity 15 is connected to the first cavity 13. A plurality of limiting ribs 16 are evenly arranged in the second cavity 15 along the width direction of the cell shell 1. The upper end of the limiting rib 16 is lower than the top of the inner shell 12, and the lower end of the limiting rib 16 is in conflict with the inner bottom surface of the outer shell 11. The setting mechanism of the limiting rib 16 in the height direction of the cell shell 1 is consistent with the setting mechanism of the elastic member. One end of the limiting rib 16 in the horizontal direction is fixedly connected to the inner wall of the outer shell 11, and the other end of the limiting rib 16 in the horizontal direction is in conflict with the outer side wall of the outer shell 11.

[0049] The second cavity 15 corresponds to the two smaller side surfaces of the inner shell 12. Inside the battery cell, the expansion force usually occurs on the large surface of the battery cell, and the expansion force generally does not occur on the small surface of the battery cell. Therefore, by providing the limiting ribs 16 in the second cavity 15, the inner shell 12 can be horizontally limited inside the outer shell 11 to prevent the outer shell 11 from moving horizontally. At the same time, the elastic member 14 in the first cavity 13 can limit the position of the inner shell 12 in the outer shell 11, thereby keeping the position of the inner shell 12 in the outer shell 11 fixed.

[0050] The elastic member 14 is provided with a plurality of first liquid permeable holes 141 evenly arranged along the height direction of the battery cell shell 1, so that the coolant entering the first cavity 13 can pass through the first liquid permeable holes 141 on the elastic member 14 and flow in the length direction of the first cavity 13; the limiting rib 16 is provided with a plurality of second liquid permeable holes 161 evenly arranged along the height direction of the battery cell shell 1, so that the coolant entering the second cavity 15 can pass through the second liquid permeable holes 161 on the limiting rib 16 and flow in the length direction of the second cavity 15; the top cover 2 is provided with a liquid inlet hole 21 and a liquid outlet hole 22, and the liquid inlet hole 21 and the liquid outlet hole 22 are respectively connected to the second cavity 15 at both ends of the inner shell 12.

[0051] By adopting the above technical solution, the coolant is introduced into the second cavity 15 through the liquid inlet hole 21, and the coolant flows in the second cavity 15, thereby flowing around the annular channel formed by the first cavity 13 and the second cavity 15, and is discharged from the liquid outlet hole 22, so that the coolant can dissipate heat to the core package 3 in the inner shell 12 during the flow of the coolant in the annular chamber formed between the outer shell 11 and the inner shell 12. The outer peripheral side of the entire core package 3 can be cooled and heat exchanged by the coolant, which greatly improves the cooling and heat exchange efficiency. In this embodiment, by passing the coolant into the chamber between the inner shell 12 and the outer shell 11, the internal structure of the battery cell shell 1 can be fully utilized for heat dissipation, and there is no need to set a liquid cooling plate outside the battery cell, which facilitates the setting of the liquid cooling heat dissipation structure of the battery module.

[0052] It is worth noting that the secondary battery disclosed in this embodiment can not only limit the expansion force of the battery cell to the inside of the battery cell shell 1, but also allow the coolant to pass into the cavity between the inner shell 12 and the outer shell 11, making full use of the internal structure of the battery cell shell 1 for heat dissipation without setting a liquid cooling plate outside the battery cell.

[0053] In order to achieve heat dissipation of the bottom surface of the core package 3, the present embodiment has a third cavity 17 between the outer bottom surface of the inner shell 12 and the inner bottom surface of the outer shell 11. A plurality of support ribs 18 are arranged at intervals in the third cavity 17 along the length direction of the battery cell shell 1. The length direction of the support ribs 18 is perpendicular to the length direction of the battery cell shell 1. Through the arrangement of the support ribs 18, on the one hand, the inner shell 12 placed inside the outer shell 11 is supported, and on the other hand, the third cavity 17 is formed between the inner shell 12 and the outer shell 11. A plurality of third liquid permeable holes 181 are arranged on the support ribs 18, so that the coolant can pass through each support rib 18 through the third liquid permeable holes 181, so that the coolant can flow in the third cavity 17.

[0054] With the above-mentioned structural arrangement, the coolant will enter the third cavity 17 while flowing in the first cavity 13 and the second cavity 15, and flow in the third cavity 17 through the third liquid-permeable hole 181, thereby dissipating heat for the bottom surface of the core package 3, thereby achieving heat dissipation for the five surfaces of the entire core package 3, greatly improving the heat dissipation efficiency of the battery cell.

[0055] In this embodiment, at least one reinforcing rib 182 is provided on the support rib 18 and is perpendicular to the support rib 18. The provision of the reinforcing rib 182 can improve the structural strength of the support rib 18 and prevent the inner shell 12 from being displaced in the height direction of the battery cell shell 1 inside the outer shell 11.

[0056] It is worth noting that in the manufacturing process of the battery cell shell 1 of this embodiment, the elastic member 14, the limiting ribs 16 and the supporting ribs 18 are first assembled on the inner wall of the outer shell 11 in sequence, and finally the inner shell 12 is assembled into the outer shell 11. This facilitates the assembly and manufacturing of the battery cell shell 1 and improves the assembly efficiency.

[0057] In this embodiment, the top of the inner shell 12 is higher than the top of the outer shell 11, and the bottom surface of the top cover 2 is provided with a sealing groove 23 which is sealed and connected with the top of the outer shell 11. With this arrangement, during the assembly process of the top cover 2 and the battery cell shell 1, the top of the inner shell 12 can be inserted into the sealing groove 23, and then the sealing welding between the top cover 2 and the inner shell 12 is achieved by laser penetration welding, so that a sealed chamber is formed between the top cover 2 and the inner shell 12, which is convenient for the core pack 3 to work reliably in the above-mentioned sealed chamber, and at the same time, the coolant introduced into the chamber between the outer shell 11 and the inner shell 12 is prevented from entering the chamber of the inner shell 12, thereby improving the sealing and safety of the secondary battery.

[0058] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A secondary battery, characterized in that: The battery cell shell (1) comprises a battery cell shell (1), a top cover (2) and a core pack (3), wherein the battery cell shell (1) comprises an outer shell (11) and an inner shell (12) arranged in the inner cavity of the outer shell (11), wherein two opposite large surfaces of the inner shell (12) and the outer shell (11) respectively have a first cavity (13), wherein a plurality of elastic members (14) are evenly arranged in the first cavity (13), wherein one end of the elastic member (14) is fixedly connected to the inner wall of the first outer shell (11), and the other end of the elastic member (14) is in contact with the large surface of the inner shell (12), wherein the core pack (3) is accommodated in the inner shell (12), and the top cover (2) is arranged on the top of the battery cell shell (1) and is respectively sealed and connected to the top ends of the outer shell (11) and the inner shell (12); A plurality of elastic members (14) are evenly arranged in the first cavity (13) along the length direction of the battery cell shell (1), the upper end of the elastic member (14) is lower than the top end of the inner shell (12), and the lower end of the elastic member (14) is in contact with the inner bottom surface of the outer shell (11); The other two opposite sides of the inner shell (12) and the outer shell (11) respectively have second cavities (15), and the second cavities (15) are connected to the first cavities (13); A plurality of limiting ribs (16) are evenly arranged in the second cavity (15) along the width direction of the battery cell shell (1), one end of the limiting rib (16) in the horizontal direction is fixedly connected to the inner wall of the outer shell (11), and the other end of the limiting rib (16) in the horizontal direction abuts against the outer wall of the outer shell (11); A plurality of first liquid-permeable holes (141) are evenly arranged on the elastic member (14) along the height direction of the battery cell housing (1), and a plurality of second liquid-permeable holes (161) are evenly arranged on the limiting rib (16) along the height direction of the battery cell housing (1); The top cover (2) is provided with a liquid inlet hole (21) and a liquid outlet hole (22), and the liquid inlet hole (21) and the liquid outlet hole (22) are respectively connected to the second cavities (15) at both ends of the inner shell (12).

2. The secondary battery according to claim 1, wherein: The elastic member (14) is a flat plate, and the angle between the flat plate and the large surface of the inner shell (12) is an acute angle.

3. The secondary battery according to claim 1, wherein: The elastic member (14) has a specific cross-sectional shape, which is a "<" shape, a ">" shape, a "C" shape, a "U" shape or an "S" shape.

4. The secondary battery according to claim 1, wherein: The outer wall of the outer shell (11) corresponding to the first cavity (13) is recessed to form at least one reinforcement portion (111).

5. The secondary battery according to claim 1, wherein: A third cavity (17) is provided between the outer bottom surface of the inner shell (12) and the inner bottom surface of the outer shell (11), a plurality of support ribs (18) are arranged at intervals in the third cavity (17), the length direction of the support ribs (18) is perpendicular to the length direction of the battery cell shell (1), and a plurality of third liquid-permeable holes (181) are provided on the support ribs (18).

6. The secondary battery according to claim 5, characterized in that: The support rib (18) is also provided with at least one reinforcing rib (182) vertically connected to the support rib (18).

7. The secondary battery according to claim 1, wherein: The top end of the inner shell (12) is higher than the top end of the outer shell (11), and the bottom surface of the top cover (2) is provided with a sealing groove (23) which is sealedly connected to the top end of the outer shell (11).

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