Buffer beam for cylindrical battery cell and battery pack

Abstract

The utility model relates to the field of batteries, particularly provides a battery, and aims to solve the problem that the shock resistance of the bottom of the conventional battery is poor. In order to achieve the purpose, the utility model provides the buffer beam for the cylindrical battery cell, the buffer beam comprises a first part and a second part in the height direction, at least one side surface of the first part is provided with an arc surface corresponding to the side surface of the cylindrical battery cell, and the arc surface is connected with the side surface of the cylindrical battery cell; the second part protrudes out of the cylindrical battery cell, and the end part of the second part is connected with the bottom plate.

Description

Technical Field

[0001] The utility model relates to the field of batteries, and particularly provides a buffer beam and a battery pack for cylindrical battery cells. Background Art

[0002] With the increasingly wide application of power battery technology in daily life, the safety performance of battery packs has received more and more attention.

[0003] A problem currently faced is that battery packs are vulnerable to impacts, which affects their use. The impacts on battery packs mainly come from the impacts on the bottom of the battery pack. Especially when the battery pack is applied to a vehicle, such as when the battery pack is set at the bottom of the vehicle, when the bottom of the vehicle collides with an obstacle, the bottom of the battery pack is easily subjected to a large impact. At present, there are few applications for reducing the impact on the bottom of the battery, and traditional solutions cannot meet the requirements.

[0004] Correspondingly, there is a need in the art for a new buffer beam and battery pack for cylindrical battery cells to solve the above problems. Summary of the Utility Model

[0005] The utility model aims to solve the above technical problems, that is, to solve the problem of poor impact resistance at the bottom of the existing battery.

[0006] In a first aspect, the utility model provides a buffer beam for cylindrical battery cells, characterized in that the buffer beam includes a first part and a second part in its height direction. At least one side of the first part has an arc surface corresponding to the side surface of the cylindrical battery cell, and the arc surface is connected to the side surface of the cylindrical battery cell; the second part protrudes from the cylindrical battery cell, and the end of the second part is connected to the bottom plate.

[0007] The advantages of the above settings are as follows: It can avoid the direct contact between the cylindrical battery cell and the bottom plate subjected to the impact force, so that all the impact forces are concentrated on the buffer beam. The impact force will be transmitted from the second part of the buffer beam to the first part, and then from the arc surface of the first part to the side surface of the cylindrical battery cell. Since the utility model connects the arc surface of the buffer beam with the side surface of the cylindrical battery cell, the connection area between the side surface of the cylindrical battery cell and the buffer beam can be increased, thereby reducing the impact on the cylindrical battery cell, improving the impact resistance of the battery, reducing the possibility of thermal runaway of the battery, and protecting the battery from damage.

[0008] In a preferred technical solution of the above buffer beam for cylindrical battery cells, the buffer beam is a plate-like structure formed in a wavy shape along its length direction, and both side surfaces of the plate-like structure have arc surfaces corresponding to the side surfaces of the cylindrical battery cells.

[0009] The advantages of the above settings are as follows: The corrugated structures on the two relatively large sides of the plate-shaped structure can increase the connection area between the buffer beam and the side surface of the cylindrical battery cell as much as possible, thereby increasing the force-bearing area of the cylindrical battery cell and further ensuring the safety performance of the battery.

[0010] In the preferred technical solution of the buffer beam for the cylindrical battery cell described above, at least one of the first part and the second part is internally embedded with a metal part.

[0011] The advantages of the above settings are as follows: It can improve the structural strength of the buffer beam, avoid directly impacting the battery due to the damage of the buffer beam, further improve the impact resistance of the cylindrical battery cell, and reduce the possibility of thermal runaway of the battery pack.

[0012] In the preferred technical solution of the buffer beam for the cylindrical battery cell described above, a glue groove is formed on the bottom plate, and the end of the second part is arranged in the glue groove.

[0013] The advantages of the above settings are as follows: On the basis of ensuring the connection strength, the structural glue can increase the connection area between the bottom plate and the buffer beam, so that when the bottom plate is subjected to an impact force, the impact force transmitted to the buffer beam can be reduced, and further the impact force transmitted to the cylindrical battery cell can be further reduced, further improving the safety performance of the battery.

[0014] In the preferred technical solution of the buffer beam for the cylindrical battery cell described above, the cross-sectional area of the glue groove in the first direction is larger than the cross-sectional area of the end in the first direction.

[0015] The advantages of the above settings are as follows: It can further increase the bonding area between the glue groove and the end of the second part, further reduce the impact force transmitted to the buffer beam, and further improve the safety performance of the battery pack.

[0016] In the preferred technical solution of the buffer beam for the cylindrical battery cell described above, the thickness direction of the bottom plate includes a first surface facing the cylindrical battery cell and a second surface away from the cylindrical battery cell. A convex platform is formed on the first surface so that a groove is formed at the position of the second surface corresponding to the convex platform, and the glue groove shares at least part of the side wall with the convex platform.

[0017] The advantages of the above settings are as follows: When an upward impact is received at the bottom wall of the glue groove on the bottom plate, the convex platform sharing the side wall can provide a deformation space for the glue groove, thereby prolonging the action time of the force, achieving the effect of buffering the impact force, and further reducing the force transmitted to the buffer beam, further protecting the battery from damage. In addition, this setting method can also facilitate the stamping forming of the glue groove.

[0018] In the preferred technical solution of the buffer beam for the cylindrical battery cell, the cross-sectional area of ​​the end of the second portion in the first direction is larger than the cross-sectional area of ​​the remaining portion of the buffer beam in the first direction.

[0019] The advantage of the above arrangement is that: since the cross-sectional area of ​​the end of the second part in the first direction is larger than the cross-sectional area of ​​the remaining part of the buffer beam in the first direction, the connection area between the bottom plate and the buffer beam can be increased, thereby reducing the impact force transmitted to the buffer beam, and further reducing the force transmitted to the cylindrical battery cell, further improving the safety performance of the cylindrical battery cell.

[0020] In the preferred technical solution of the buffer beam for cylindrical battery cells, a protective layer is provided on the bottom surface of the battery cell group, and the battery cell group includes a plurality of cylindrical battery cells.

[0021] The advantage of the above arrangement is that when thermal runaway occurs in the cylindrical battery cell, the bottom of the cylindrical battery cell is protected by a protective layer and will not be affected by the high-temperature gas or will be less affected, thereby playing a role of safety protection.

[0022] In the preferred technical solution of the buffer beam for the cylindrical battery cell, an elastic layer is provided between the protective layer and the bottom surface.

[0023] The advantage of the above arrangement is that since an elastic layer is provided between the protective layer and the bottom surface, the surface contour tolerance of the bottom surface of the entire cylindrical battery cell module can be absorbed by the elastic layer. When pouring glue, the battery cell group will be turned upside down for pouring glue, so that the glue pouring tooling can fit tightly with the battery cell group, thereby preventing the potting glue from leaking to the explosion-proof valve of the cylindrical battery cell, which would hinder the normal opening of the explosion-proof valve of the cylindrical battery cell.

[0024] In the preferred technical solution of the buffer beam for the cylindrical battery cell, an exhaust channel is formed between two adjacent buffer beams and the bottom plate and the protective layer.

[0025] The advantage of the above arrangement is that when the protective layer of a cylindrical battery cell is broken due to thermal runaway, harmful hot gas will flow through the exhaust channel, and the protective layer can prevent the harmful hot gas from corroding the cylindrical battery cell between two adjacent buffer beams.

[0026] On the other hand, the utility model further provides a battery pack, which includes a accommodating cavity surrounded by side walls and a bottom plate, a battery cell group is arranged in the accommodating cavity, and the battery cell group includes a plurality of cylindrical battery cells; the battery pack also includes the buffer beam described in any of the above embodiments.

[0027] After the battery pack has the above-mentioned buffer beam, the overall impact resistance of the battery pack can be improved and the service life of the battery pack can be increased.

[0028] In the preferred technical solution of the above battery pack, a gap is formed between adjacent cylindrical battery cells, the first part is disposed in the gap, and the gap is filled with potting glue.

[0029] The advantages of the above arrangement are as follows: After the potting glue is cured, each cylindrical battery cell and the buffer beam are integrated. On the one hand, due to the characteristics of the potting glue, the potting glue itself can absorb part of the impact energy, thereby achieving a buffering effect and reducing the impact force on the battery. On the other hand, since each cylindrical battery cell and the buffer beam are integrated, the overall structural strength of the battery can be improved. When the buffer beam receives an impact force, due to the high structural strength of the battery, the impact on the battery can be reduced, and the occurrence of thermal runaway can be further reduced.

[0030] Solution 1: A buffer beam for cylindrical battery cells, characterized in that the buffer beam includes a first part and a second part in its height direction, at least one side surface of the first part has an arc surface corresponding to the side surface of the cylindrical battery cell, and the arc surface is connected to the side surface of the cylindrical battery cell; the second part protrudes from the cylindrical battery cell, and the end of the second part is connected to the bottom plate.

[0031] Solution 2: The buffer beam for cylindrical battery cells according to Solution 1, characterized in that the buffer beam is a plate-like structure formed in a wavy shape along its length direction, and both side surfaces of the plate-like structure have arc surfaces corresponding to the side surfaces of the cylindrical battery cells.

[0032] Solution 3: The buffer beam for cylindrical battery cells according to Solution 1 or 2, characterized in that at least one of the first part and the second part is internally embedded with a metal part.

[0033] Solution 4: The buffer beam for cylindrical battery cells according to Solution 1 or 2, characterized in that a glue groove is formed on the bottom plate, and the end of the second part is disposed in the glue groove.

[0034] Solution 5: The buffer beam for cylindrical battery cells according to Solution 4, characterized in that the bottom plate includes a first surface facing the cylindrical battery cell and a second surface away from the cylindrical battery cell in the thickness direction, a boss is formed on the first surface, so that a groove is formed at the position of the second surface corresponding to the boss, and the glue groove and the boss share at least part of the side wall.

[0035] Solution 6: The buffer beam for cylindrical battery cells according to Solution 1, characterized in that the cross-sectional area of the end in the first direction is larger than the cross-sectional area of the remaining part of the buffer beam in the first direction.

[0036] Solution 7: The buffer beam for cylindrical battery cells according to Solution 1, characterized in that a protective layer is provided on the bottom surface of the battery cell group, and the battery cell group includes a plurality of cylindrical battery cells.

[0037] Solution 8: The buffer beam for cylindrical battery cells according to Solution 7, characterized in that an elastic layer is provided between the protective layer and the bottom surface.

[0038] Solution 9: The buffer beam for cylindrical battery cells according to Solution 7, characterized in that an exhaust channel is formed between two adjacent buffer beams, the bottom plate and the protective layer.

[0039] Solution 10: A battery pack, characterized in that it includes a receiving cavity surrounded by a side wall and a bottom plate, a battery cell group is arranged in the receiving cavity, and the battery cell group includes a plurality of cylindrical battery cells; the battery pack further includes the buffer beam according to any one of Solutions 1 to 9.

[0040] Solution 11: The battery pack according to Solution 10, characterized in that a gap is formed between adjacent cylindrical battery cells, the first part is arranged in the gap, and the gap is filled with potting glue. Description of the Drawings

[0041] The preferred embodiments of the present invention will be described below with reference to the drawings. In the drawings:

[0042] Figure 1 is the cross-sectional view (I) of the battery cell group of the present invention;

[0043] Figure 2 is the structural schematic diagram of the buffer beam of the battery cell group of the present invention;

[0044] Figure 3 is the cross-sectional view of the buffer beam of the battery cell group of the present invention;

[0045] Figure 4 is the cross-sectional view (II) of the battery cell group of the present invention;

[0046] Figure 5 is the partial structural schematic diagram of the buffer beam of the battery cell group of the present invention;

[0047] Figure 6 is Figure 5 the cross-sectional view at A-A in

[0048] Figure 7 is the structural schematic diagram of the bonding of the glue groove on the bottom plate of the present invention and the buffer beam;

[0049] Figure 8 is the structural schematic diagram (I) of the battery cell group of the present invention;

[0050] Figure 9It is the structural schematic diagram (II) of the battery cell group of the present utility model;

[0051] Figure 10 It is the structural schematic diagram of the protection structure of the present utility model;

[0052] Figure 11 It is Figure 10 The enlarged view of part A in

[0053] Figure 12 It is the structural schematic diagram (III) of the battery cell group of the present utility model;

[0054] Figure 13 It is the partial sectional view of the battery cell group of the present utility model;

[0055] Figure 14 It is the partial structural schematic diagram of the battery cell group of the present utility model;

[0056] Figure 15 It is Figure 14 The sectional view at B - B in

[0057] List of reference numerals:

[0058] 1 - Cylindrical battery cell; 11 - Bottom surface; 2 - Buffer beam; 21 - First part; 22 - Second part; 23 - Composite layer; 231 - First composite layer; 232 - Second composite layer; 24 - Reinforcing member; 3 - Potting glue; 4 - Bottom plate; 41 - First surface; 411 - Boss; 412 - Glue groove; 42 - Second surface; 421 - Groove; 5 - Protection structure; 51 - Elastic layer; 52 - Protection layer; 521 - Scratch; 53 - Fixing member; 54 - Depression part 6 - Exhaust passage. Detailed implementation manners

[0059] The preferred implementation manners of the present utility model will be described below with reference to the accompanying drawings. Those skilled in the art should understand that these implementation manners are only used to explain the technical principle of the present utility model and are not intended to limit the protection scope of the present utility model. Those skilled in the art can adjust them as needed to adapt to specific application scenarios.

[0060] It should be noted that in the description of the present utility model, the terms indicating the direction or positional relationship such as "upper", "lower", etc. are based on the direction or positional relationship shown in the drawings. This is only for the convenience of description and does not indicate or imply that the device or element 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 utility model.

[0061] It should be noted that in the description of the present utility model, unless otherwise clearly specified and defined, the terms "connection" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected, or indirectly connected through an intermediate medium. For those skilled in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances. In addition, in the description of the present utility model, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0062] As Figures 1 to 5 shown, in order to solve the problem that the existing battery has poor anti-impact performance at the bottom. The present utility model provides a buffer beam 2 for a cylindrical battery cell 1. The buffer beam 2 includes a first part 21 and a second part 22 in its height direction. At least one side surface of the first part 21 has an arc surface corresponding to the side surface of the cylindrical battery cell 1, and the arc surface is connected to the side surface of the cylindrical battery cell 1; the second part 22 protrudes from the cylindrical battery cell 1, and the end of the second part 22 is connected to the bottom plate 4.

[0063] Through this kind of setting, when the bottom plate 4 is impacted, since the second part 22 protrudes from the cylindrical battery cell 1, it can avoid the direct contact between the cylindrical battery cell 1 and the bottom plate 4 that receives the impact force, so that all the impact forces are concentrated on the buffer beam 2. The impact force will be transmitted from the second part 22 of the buffer beam 2 to the first part 21, and then transmitted from the arc surface of the first part 21 to the side surface of the cylindrical battery cell 1. Since the present utility model is connected to the side surface of the cylindrical battery cell 1 through the arc surface of the buffer beam 2, the connection area between the side surface of the cylindrical battery cell 1 and the buffer beam 2 can be increased, thereby reducing the impact on the cylindrical battery cell 1, improving the anti-impact performance of the battery, reducing the possibility of thermal runaway of the battery, and protecting the battery from damage.

[0064] The present utility model provides a battery pack. The lower box body of the battery pack includes a receiving cavity surrounded by side walls and a bottom plate 4. The side walls can be square annular or circular annular, and the present utility model does not limit its specific shape; that is, the side walls and the bottom plate 4 surround and form the lower box body, and the space inside the lower box body is the receiving cavity. The lower box body can be a trough-shaped structure with an open top. Further, a sealing cover can be provided at the open end so that the sealing cover and the trough-shaped structure surround and form a closed receiving cavity. The lower box body and the sealing cover are collectively called the battery pack box body.

[0065] The battery pack further includes a battery cell group, and the battery cell group is arranged in the receiving cavity. Possibly, the battery cell group includes a plurality of cylindrical battery cells 1. When the cylindrical battery cells 1 are grouped, generally, the cylindrical battery cells 1 will be distributed in multiple rows and columns, but the present utility model does not exclude the case of single-row arrangement. The battery pack of the present utility model further includes a buffer beam 2. The buffer beam 2 is in its height direction (such as Figure 1in the y - direction) includes a first part 21 and a second part 22. At least one side surface of the first part 21 has an arc surface corresponding to the side surface of the cylindrical battery cell 1, and the arc surface is connected to the side surface of the cylindrical battery cell 1.

[0066] In a specific embodiment, one side surface of the first part 21 has an arc surface corresponding to the side surface of the cylindrical battery cell 1. That is, the first part 21 is connected to the side surfaces of a row of cylindrical battery cells 1, and a single buffer beam 2 is used to support a row of cylindrical battery cells 1.

[0067] In another specific embodiment, both side surfaces of the first part 21 have arc surfaces corresponding to the side surfaces of the cylindrical battery cell 1. That is, both side surfaces of the first part 21 are connected to the side surfaces of a row of cylindrical battery cells 1, and a single buffer beam 2 is used to support two rows of cylindrical battery cells 1.

[0068] There will be gaps between the side surfaces of adjacent cylindrical battery cells 1. In the present utility model, potting glue 3 is filled in the gaps so that each cylindrical battery cell 1 forms an integral body. The first part 21 is arranged in the gaps between adjacent cylindrical battery cells 1. Potting glue 3 can be filled in the gaps between the cylindrical battery cells 1 or between the cylindrical battery cells 1 and the first part 21. Among them, the second part 22 protrudes from the bottom of the cylindrical battery cell 1, and the end of the second part 22 is connected to the bottom plate 4, so that each cylindrical battery cell 1 is suspended above the bottom plate 4 by the support of the buffer beam 2, that is, there is a gap between the bottom surface 11 of each cylindrical battery cell 1 and the bottom plate 4.

[0069] Optionally, the connection between the arc surface and the side surface of the cylindrical battery cell 1 can be that the arc surface and the side surface of the cylindrical battery cell 1 are connected through a connecting body. For example, the arc surface and the side surface of the cylindrical battery cell 1 are connected through the above - mentioned potting glue 3, or the arc surface and the side surface of the cylindrical battery cell 1 are welded and connected, etc. It can be understood that the potting glue 3 of the present utility model can be epoxy resin potting glue, silicone resin potting glue, polyurethane potting glue, foaming glue, etc. As long as it can bond the cylindrical battery cell 1 and the buffer beam 2 together after curing to form a whole.

[0070] Through the above - mentioned arrangement, when the bottom plate 4 is impacted, since each cylindrical battery cell 1 is suspended above the bottom plate 4 by the support of the buffer beam 2, it can avoid the direct contact between the cylindrical battery cell 1 and the impacted bottom plate 4, so that all the impact forces are concentrated on the buffer beam 2. The impact force will be transmitted from the second part 22 of the buffer beam 2 to the first part 21, and then from the arc surface of the first part 21 to the side surface of the cylindrical battery cell 1. Since the present utility model connects the arc surface of the buffer beam 2 with the side surface of the cylindrical battery cell 1, the connection area between the side surface of the cylindrical battery cell 1 and the buffer beam 2 can be increased, thereby reducing the impact on the cylindrical battery cell 1, improving the impact resistance of the battery, reducing the possibility of thermal runaway of the battery, and protecting the battery from damage.

[0071] When the potting glue 3 is disposed in the gaps between adjacent cylindrical battery cells 1 in the first part 21, after the potting glue 3 is cured, each cylindrical battery cell 1 and the buffer beam 2 are formed as a whole. On the one hand, due to the characteristics of the potting glue 3, the potting glue 3 itself can absorb part of the impact energy, thus achieving a buffering effect and reducing the impact force on the battery. On the other hand, since each cylindrical battery cell 1 and the buffer beam 2 are formed as a whole, the overall structural strength of the battery can be improved. When the buffer beam 2 receives an impact force, due to the high structural strength of the battery, the impact on the battery caused by the impact force can be reduced, and the occurrence of thermal runaway can be further reduced.

[0072] Optionally, the height of the first part 21 of the buffer beam 2 is less than the height of the battery cell. That is, the gap between two rows of battery cells of the present invention is composed of an upper gap and a lower gap. The first part 21 is disposed in the lower gap, and the upper gap and the lower gap are both filled with the potting glue 3. That is to say, the first part 21 of the present invention is not located in the entire gap, but in a part of the gap. Thus, while the buffer beam 2 can provide sufficient support for the cylindrical battery cells, the weight of the buffer beam 2 can also be reduced, thereby reducing the weight of the entire battery pack. Optionally, the above-mentioned gap can form a reasonable avoidance, for example, facilitating the cooling structure or other structures to be disposed in the upper gap. Of course, this is not restrictive. The first part 21 of the present invention can also be located in the entire gap, and these do not deviate from the principle of the present invention and are all within the protection scope of the present invention.

[0073] In one embodiment, the number of the buffer beams 2 of the present invention can be set based on the number of the cylindrical battery cells 1. Preferably, the buffer beams 2 are evenly spaced on the battery cell group. For example, a buffer beam 2 is provided every two rows of cylindrical battery cells 1. Of course, the number of spaced cylindrical battery cells 1 is not restrictive. This setting method can, on the one hand, enable the battery cell group to be stably supported on the bottom plate 4; on the other hand, it can share the impact force, thereby reducing the damage to the cylindrical battery cells 1. Possibly, a water-cooling plate can be disposed in the gap between two rows of cylindrical battery cells 1 between two adjacent buffer beams 2 to facilitate taking away the heat generated during the operation of the battery pack to play a cooling role.

[0074] As a possible implementation manner, the buffer beam 2 is a plate-like structure formed in a wavy shape along its length direction. Both sides of the plate-like structure have arc surfaces corresponding to the side surfaces of the cylindrical battery cells 1. For example, both sides of the buffer beam 2 are formed in a wavy structure along the length direction, and the arc surfaces in the wavy structure are the above-mentioned arc surfaces, that is, the wavy structure is composed of a plurality of arc surfaces connected end to end. It can be understood that the two sides of the plate-like structure refer to the two surfaces in the thickness direction of the plate-like structure, that is, the two largest surfaces of the plate-like structure.

[0075] In the above setting method, when the first part 21 of the buffer beam 2 is disposed in the potting adhesive 3 between adjacent cylindrical battery cells 1, the wavy structures on both sides are completely adhesively bonded to the cylindrical battery cells 1. The wavy structures on the two large surfaces of the plate-shaped structure can increase the connection area between the buffer beam 2 and the side surfaces of the cylindrical battery cells 1 as much as possible, thereby increasing the force-bearing area of the cylindrical battery cells 1 and further ensuring the safety performance of the battery. It can be understood that although the present utility model is introduced with arc surfaces disposed on both side surfaces of the plate-shaped structure, this is not intended to limit the protection scope of the present utility model. For example, arc surfaces can be provided only on one side surface of the plate-shaped structure, etc. These do not deviate from the principle of the present utility model and are all within the protection scope of the present utility model.

[0076] The structure of the buffer beam 2 of the present utility model will be introduced below.

[0077] Example 1. Refer to Figure 5 and Figure 6 , the buffer beam 2 includes a composite layer 23 and a reinforcing member 24 embedded in the composite layer 23. Preferably, the entire outer layer of the buffer beam 2 is the composite layer 23, and the reinforcing member 24 is embedded in the entire length direction within the composite layer 23. The reinforcing member 24 is preferably a metal plate, specifically, it can be a high-strength steel plate, or a plastic skeleton, etc. The composite layer 23 can include glass fiber, resin, and plastic, or a composite material containing at least two of them.

[0078] Since the buffer beam 2 includes the composite layer 23 and the reinforcing member 24 embedded in the composite layer 23, the structural strength of the buffer beam 2 can be improved, avoiding direct impact on the cylindrical battery cells 1 due to damage to the buffer beam 2, further improving the impact resistance of the cylindrical battery cells 1, and reducing the possibility of thermal runaway of the battery pack. On the other hand, when the reinforcing member 24 is a metal plate, the composite layer 23 can also prevent the metal plate from corroding and can be insulated, improving the safety performance of the battery.

[0079] Further, the buffer beam 2 includes a first composite layer 231, a metal plate 24, and a second composite layer 232 along its thickness direction. That is, after the first composite layer 231, the second composite layer 232 and the metal plate are molded, they can have a certain bonding strength, so that the metal plate is embedded between the first composite layer 231 and the second composite layer 232. In this case, wavy structures can be formed in the length directions of the first composite layer 231 and the second composite plate. Thus, on the basis that the buffer beam 2 is a plate-shaped structure to increase the connection area with the cylindrical battery cells 1, the wavy structures on the first composite layer 231 and the second composite layer 232 can further increase the connection area with the cylindrical battery cells 1, and further reduce the impact force received by the cylindrical battery cells 1.

[0080] Example 2. Refer to Figure 3, the buffer beam 2 is an integrally formed plate-like structure with wavy shapes on both sides. Or it is an integrally formed plate-like structure with a wavy shape on one side. This can facilitate the production of the buffer beam 2 and the forming process.

[0081] The following introduces the possible implementation manners of the connection between the bottom plate 4 and the end of the buffer beam 2.

[0082] The first possible implementation manner is as Figure 7 shown. A glue groove 412 is formed on the bottom plate 4. The end of the second part 22 is disposed in the glue groove 412, that is, the glue groove 412 is filled with glue, and the end of the second part 22 is disposed in the glue groove 412 so that after the glue is cured, the end of the second part 22 is fixedly connected to the bottom plate through the glue in the glue groove 412. Among them, the specific shape of the glue groove 412 in the present invention is not limited. It is preferably a U-shaped groove, which can reduce the stress concentration at the bending part and enhance the structural strength of the glue groove 412, so as to avoid deformation or even fracture when subjected to an impact force. Of course, it can also be a V-shaped groove, etc.

[0083] Since the glue groove 412 is filled with structural glue, in the present invention, the glue groove 412 on the bottom plate 4 is adhesively bonded to the end of the second part 22 of the buffer beam 2. On the basis of ensuring the connection strength, the structural glue can increase the connection area between the bottom plate 4 and the buffer beam 2. Therefore, when the bottom plate 4 is subjected to an impact force, the impact force transmitted to the buffer beam 2 can be reduced, and further the impact force transmitted to the cylindrical battery cell 1 can be further reduced, thereby further improving the safety performance of the battery.

[0084] Furthermore, the cross-sectional area of the glue groove 412 in the first direction is larger than the cross-sectional area of the end of the second part 22 in the first direction. This can further increase the adhesive bonding area between the glue groove 412 and the end of the second part 22, further reduce the impact force transmitted to the buffer beam 2, and further improve the safety performance of the battery pack. Among them, the cross-sectional area of the glue groove 412 in the first direction, that is, after the battery pack is installed, the horizontal cross-sectional area of the glue groove 412 in the horizontal direction. Similarly, the end of the second part 22 is also the cross-sectional area in the horizontal direction, such as Figure 7 the x direction in

[0085] As a possible implementation, in the thickness direction of the bottom plate 4, there are a first surface 41 facing the cylindrical battery cell 1 and a second surface 42 away from the cylindrical battery cell 1. A boss 411 is formed on the first surface 41, so that a groove 421 is formed at the position of the second surface 42 corresponding to the boss 411, and the glue groove 412 shares at least part of the side wall with the boss 411. For example, the bosses 411 are located on opposite sides of the glue groove 412, and the bosses 411 on both sides share at least part of the side wall with the glue groove 412. Specifically, if the glue groove 412 includes a first side wall and a second side wall, the first side wall and the second side wall are oppositely arranged, the boss 411 on one side includes the above-mentioned first side wall, and the boss 411 on the other side includes the second side wall. Or the boss 411 is an annular boss 411, so that a glue groove 412 is formed in the middle of the annular boss 411. As long as the glue groove 412 can share at least part of the side wall with the boss 411, it does not deviate from the principle of the present invention and is within the protection scope of the present invention.

[0086] In the above setting method, when an upward impact is applied to the bottom wall of the glue groove 412 on the bottom plate 4, the bosses 411 on both sides thereof can provide a deformation space for the glue groove 412, so as to extend the action time of the force, achieve the effect of buffering the impact force, and further reduce the force transmitted to the buffer beam 2, further protecting the battery from damage. In addition, this setting method can also facilitate the stamping forming of the glue groove 412.

[0087] The second possible implementation, referring to Figure 1 , the cross-sectional area of the end of the second part 22 in the first direction is larger than the cross-sectional area of the rest of the buffer beam 2 in the first direction. Wherein, the first direction refers to the horizontal direction after the battery pack is installed, such as the x direction in Figure 1 . The cross-section of the buffer beam 2 in the longitudinal direction (the y direction in Figure 1 ) is preferably in an inverted T shape, and the end of the second part 22 can be a plate-like structure with a cross-section larger than that of the rest of the part. Further, the end of the second part 22 and the bottom plate 4 can be bonded by structural glue, so as to improve the connection strength between the buffer beam 2 and the bottom plate 4, make them form an integral body, and further improve the impact resistance. Less preferably, the end of the second part 22 and the bottom plate 4 can also be connected by means such as screw connection or riveting.

[0088] Since the cross-sectional area of the end of the second part 22 in the first direction is larger than the cross-sectional area of the rest of the buffer beam 2 in the first direction, the connection area between the bottom plate 4 and the buffer beam 2 can be increased, so that the impact force transmitted to the buffer beam 2 can be reduced, and further the force transmitted to the cylindrical battery cell 1 can be reduced, further improving the safety performance of the cylindrical battery cell 1.

[0089] Among them, the two possible implementation manners of connecting the bottom plate 4 and the end of the buffer beam 2 introduced above can be used interchangeably or cross-matched to form a new implementation manner. These simple changes do not deviate from the principle of the present utility model and are all within the protection scope of the present utility model.

[0090] In the above implementation manner, since each cylindrical battery cell 1 is suspended above the bottom plate 4 by the support of the buffer beam 2, the bottom surface 11 of each cylindrical battery cell 1 is separated from the protection of the bottom plate 4. If a certain cylindrical battery cell 1 undergoes thermal runaway, the explosion-proof valve at the bottom of the cylindrical battery cell 1 will open, so that it is very easy for the bottom surface 11 of other cylindrical battery cells 1 to be affected by the eruption, thus easily causing thermal runaway of the entire battery pack. To avoid this phenomenon, as Figures 8 to 15 shown, the battery pack of the present utility model further includes a protection structure 5. The protection structure 5 includes a protection layer 52. The protection layer 52 is provided on the bottom side of the battery cell group. The protection layer 52 is provided with a weak area, and the weak area corresponds to the explosion-proof valves of some or all of the cylindrical battery cells 1 in the battery cell group. Among them, an explosion-proof valve can be provided on the bottom surface 11 of each cylindrical battery cell 1. The protection layer 52 of the present utility model can cover each bottom surface 11 and each explosion-proof valve, and the protection layer 52 is provided with a weak area at the position corresponding to the explosion-proof valve. It can be understood that the bottom surface 11 of the cylindrical battery cell 1 is usually the position where the negative electrode of the cylindrical battery cell 1 is located. When the cylindrical battery cells 1 are grouped, the bottom surfaces 11 of the cylindrical battery cells 1 are all located on the bottom side of the battery cell group.

[0091] The above setting manner enables the explosion-proof valve on the bottom surface 11 of a certain or some cylindrical battery cells 1 to open when thermal runaway occurs in the cylindrical battery cells 1. Since the protection layer 52 is provided with a weak area at the position corresponding to the explosion-proof valve, the weak area is washed open after the explosion-proof valve opens, that is, high-temperature gas, sparks, high-temperature solid particles, etc. erupt through the weak area. Since the bottoms of other cylindrical battery cells 1 are protected by the protection layer 52, they will not be affected by the eruption or will be less affected by the eruption, thus being able to play a role in safety protection.

[0092] Among them, the specific form of the weak area of the present utility model includes various types. For example, the protection layer 52 is integrally formed, and the thickness of the weak area is less than that of other areas, so that the weak area can be washed open when the explosion-proof valve opens. Or the weak area is a notch 521, so that after the explosion-proof valve opens, the corresponding part of the protection layer 52 will be washed open along the notch 521. As long as the weak area can be washed open after the explosion-proof valve opens, the specific form of the weak area can be adjusted.

[0093] Preferably, the protection layer 52 can be insulated. For example, the protection layer 52 is a high-temperature resistant material such as mica sheet or ceramic. It can play an insulating role for other cylindrical battery cells 1 when the explosion-proof valve opens, and can also play a role in high-voltage safety protection.

[0094] As a possible implementation, the shape of the weak area corresponds to the shape of the explosion-proof valve. For example, when the shape of the explosion-proof valve is circular, the shape of the weak area is also circular, so as to minimize the breakthrough area of the protective layer 52 and concentrate on being broken through at the explosion-proof valve, reducing the possibility of erosion to other cylindrical battery cells 1. Further, the number of weak areas can be multiple, and the positions of each weak area correspond to those of each explosion-proof valve one by one. Thus, it is convenient for the high-temperature gas, sparks, and high-temperature solid particulate matter generated after any explosion-proof valve is opened to be ejected from the corresponding weak area, avoiding affecting adjacent batteries.

[0095] As a possible implementation, referring to Figure 1 and Figure 4 , an exhaust passage 6 is formed between two adjacent buffer beams 2 and the bottom plate 4 and the protective layer 52. This setting method enables harmful hot air to flow through the exhaust passage 6 after the protective layer 52 of a certain cylindrical battery cell 1 is broken through due to thermal runaway. The protective layer 52 can prevent the harmful hot air from eroding the cylindrical battery cells 1 between two adjacent buffer beams 2.

[0096] As a possible implementation, the protective structure 5 further includes an elastic layer 51, and the elastic layer 51 is located between the protective layer 52 and the battery cell group. The elastic layer 51 is preferably foam, and of course it can also be silicone rubber, etc. It can meet the lightweight requirements of the battery pack. Since the elastic layer 51 is located between the protective layer 52 and the battery cell group, the surface profile tolerance of the bottom surface 11 of the cylindrical battery cell group 1 can be absorbed through the elastic layer 51. When pouring glue, the battery cell group will be turned upside down for pouring glue, so that the pouring glue tooling can be closely attached to the battery cell group, thereby preventing the potting glue 3 from leaking to the explosion-proof valve of the cylindrical battery cell 1 and causing obstruction to the normal opening of the explosion-proof valve of the cylindrical battery cell 1.

[0097] As a possible implementation, the protective structure 5 further includes a fixing member 53, and the fixing member 53 connects the protective layer 52 and the elastic layer 51. Thus, it prevents the elastic layer 51 and the protective layer 52 from delaminating and falling off. Among them, the number of fixing members 53 can be multiple, such as 8, etc., and they can be evenly spaced on the protective structure 5. The specific structural form of the fixing member 53 includes various types. For example, the fixing member 53 is a plastic buckle or a screw, etc.

[0098] There are various connection methods between the bottom of the battery cell group and the protective structure 5.

[0099] In the first possible implementation, the fixing member 53 passes through the elastic layer 51 and is fixed in the potting glue 3 in the gap between adjacent cylindrical battery cells 1. That is, after the potting glue 3 in the gap is cured, the fixing member 53 is locked, and then the protective structure 5 is connected to the cylindrical battery cell 1 module.

[0100] The second possible implementation manner is that the battery cell group and the elastic layer 51 are bonded by potting adhesive 3 filled in the gaps between adjacent cylindrical battery cells 1.

[0101] Possibly, the protection structure 5 of the present utility model can be multi-segmented or an integral body. When the protection structure 5 is multi-segmented, a buffer beam 2 can be arranged between two adjacent segments of the protection structure 5. For example, when a buffer beam 2 is arranged every two cylindrical battery cells 1, a segment of the protection structure 5 is provided on the upper cover of the bottom of every two cylindrical battery cells 1, and the buffer beam 2 is arranged between these two segments of the protection structure 5, so as to avoid the buffer beam 2 interfering with the protection structure 5 and affecting the use performance of the protection structure 5. When the protection structure 5 is an integral body, the buffer beam 2 can pass through the protection structure 5 and be fixed in the potting adhesive 3 in the gaps between adjacent cylindrical battery cells 1. As long as the protection structure 5 can cover the bottom of each cylindrical battery cell 1, it does not deviate from the principle of the present utility model and is within the protection scope of the present utility model.

[0102] As a possible implementation manner, referring to Figure 15 , the edge of the protection structure 5 of the present utility model includes a recessed portion 54 that is recessed towards the gaps between adjacent cylindrical battery cells 1. Among them, the recessed portion 54 can be arc-shaped. Since gaps will be formed between adjacent cylindrical battery cells 1, therefore, by forming a recessed portion 54 that is recessed towards the gaps at the edge of the protection structure 5 in the present utility model, the space at the gaps can be reasonably utilized, thereby reducing the volume of the protection structure 5 and the occupied space of the protection structure 5, and thus improving the energy density of the battery.

[0103] Furthermore, the edge of the protection structure 5 includes a plurality of recessed portions 54, and each recessed portion 54 corresponds to each gap and is recessed into each gap. For example, the battery cell group includes a whole row of first battery cell groups on one side in its width direction, and also includes a whole row of second battery cell groups on the other side in its width direction. The protection structure 5 covers the first battery cell groups, the second battery cell groups, and the battery cell groups (if any) between the first battery cell groups and the second battery cell groups. The protection structure 5 forms a recessed portion 54 that is recessed into each gap of the first battery cell groups at the edge close to the first battery cell groups, and the protection structure 5 forms a recessed portion 54 that is recessed into each gap of the second battery cell groups at the edge close to the second battery cell groups. Thereby, the space at the gaps can be utilized as much as possible, further reducing the volume of the protection structure 5 and further improving the energy density of the battery.

[0104] Among them, the battery pack of the present utility model can be applied to vehicles, and can also be applied to mobile phones, portable devices, laptop computers, ships, spacecrafts, electric toys, electric tools, etc. The vehicle can be a new energy vehicle, and the new energy vehicle can be a pure electric vehicle, a hybrid electric vehicle or an extended-range electric vehicle, etc.

[0105] It should be noted that the above embodiments are only used to illustrate the principle of the present utility model and are not intended to limit the protection scope of the present utility model. Without departing from the principle of the present utility model, those skilled in the art can adjust the above structure so that the present utility model can be applied to more specific application scenarios.

[0106] So far, the technical solutions of the present utility model have been described in conjunction with the preferred embodiments shown in the drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present utility model is obviously not limited to these specific embodiments. Without departing from the principle of the present utility model, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present utility model.

Claims

1. A buffer beam for a cylindrical battery cell, characterized in that: The buffer beam includes a first part and a second part in its height direction, at least one side surface of the first part has an arc surface corresponding to the side surface of the cylindrical battery core, and the arc surface is connected to the side surface of the cylindrical battery core; the second part protrudes from the cylindrical battery core, and the end of the second part is connected to the bottom plate.

2. The buffer beam for cylindrical battery cells according to claim 1, characterized in that: The buffer beam is a plate-like structure that is wavy along its length direction, and both side surfaces of the plate-like structure have arc surfaces corresponding to the side surfaces of the cylindrical battery core.

3. The buffer beam for cylindrical battery cells according to claim 1 or 2, characterized in that: A metal piece is embedded in at least one of the first part and the second part.

4. The buffer beam for cylindrical battery cells according to claim 1 or 2, characterized in that: A glue groove is formed on the bottom plate, and the end of the second part is arranged in the glue groove.

5. The buffer beam for cylindrical battery cells according to claim 4, characterized in that: The bottom plate includes a first surface facing the cylindrical battery cell and a second surface away from the cylindrical battery cell in the thickness direction, a boss is formed on the first surface so that a groove is formed on the second surface corresponding to the position of the boss, and the glue groove and the boss share at least part of the side wall.

6. The buffer beam for cylindrical battery cells according to claim 1, characterized in that: The cross-sectional area of ​​the end portion in the first direction is greater than the cross-sectional area of ​​the remaining portion of the buffer beam in the first direction.

7. The buffer beam for cylindrical battery cells according to claim 1, characterized in that: A protective layer is provided on the bottom surface of the battery cell group, and the battery cell group includes a plurality of cylindrical battery cells.

8. The buffer beam for cylindrical battery cells according to claim 7, characterized in that: An elastic layer is provided between the protective layer and the bottom surface.

9. The buffer beam for cylindrical battery cells according to claim 7, characterized in that: An exhaust passage is formed between two adjacent buffer beams, the bottom plate and the protective layer.

10. A battery pack, characterized in that: It comprises a containing cavity surrounded by side walls and a bottom plate, wherein a battery cell group is arranged in the containing cavity, and the battery cell group comprises a plurality of cylindrical battery cells; the battery pack further comprises a buffer beam as claimed in any one of claims 1 to 9.

11. The battery pack according to claim 10, characterized in that: A gap is formed between adjacent cylindrical battery cells, the first part is arranged in the gap, and the gap is filled with potting glue.

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