Buffer beam for cylindrical battery cell and battery pack

Abstract

The invention relates to the field of batteries, particularly provides a battery, and aims to solve the problem that the impact resistance of the bottom of an existing battery is poor. In order to achieve the purpose, the buffer beam for the cylindrical battery cell is provided, the buffer beam comprises a first part and a second part in the height direction of the buffer beam, at least one side face of the first part is provided with an arc face corresponding to the side face of the cylindrical battery cell, and the arc face is connected with the side face 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 present invention relates to the field of batteries, and in particular provides a buffer beam and a battery pack for a cylindrical battery cell. Background Art

[0002] As power battery technology is increasingly used in daily life, the safety performance of battery packs has received more and more attention.

[0003] The battery pack is easily impacted, which affects its use. This is a problem we are facing now. The impact on the battery pack mainly comes from the impact on the bottom of the battery pack, especially when the battery pack is used in a vehicle. For example, if 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 prone to a large impact. However, there are few applications for reducing the impact on the bottom of the battery, and traditional solutions cannot meet its requirements.

[0004] Accordingly, the art needs a new buffer beam and battery pack for cylindrical battery cells to solve the above problems. Summary of the invention

[0005] The present invention aims to solve the above technical problem, that is, to solve the problem that the bottom of the existing battery has poor impact resistance.

[0006] In a first aspect, the present invention provides a buffer beam for a cylindrical battery cell, characterized in that the buffer beam comprises 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 an end of the second part is connected to a bottom plate.

[0007] The advantage of the above arrangement is that it can avoid direct contact between the cylindrical battery cell and the bottom plate that is subjected to the impact force, so that all the impact force is 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 transmitted from the arc surface of the first part to the side of the cylindrical battery cell. Since the present invention connects the arc surface of the buffer beam to the side of the cylindrical battery cell, the connection area between the side of the cylindrical battery cell and the buffer beam can be increased, and then the impact on the cylindrical battery cell can be reduced, thereby improving the impact resistance of the battery, reducing the possibility of thermal runaway of the battery, and protecting the battery from damage.

[0008] In the preferred technical solution of the buffer beam for cylindrical battery cells, the buffer beam is a plate-like structure with a wave 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 cell.

[0009] The advantage of the above arrangement is that the wavy structures on the two larger sides of the plate-like structure can maximize the connection area between the buffer beam and the side of the cylindrical battery cell, thereby increasing the stress-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 cylindrical battery cells, a metal piece is embedded in at least one of the first part and the second part.

[0011] The advantages of the above arrangement are that it can improve the structural strength of the buffer beam, avoid direct impact on the battery due to damage to 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 cylindrical battery cells, a glue groove is formed on the bottom plate, and the end of the second part is arranged in the glue groove.

[0013] The advantage of the above arrangement is that, on the basis of ensuring the connection strength, the connection area between the base plate and the buffer beam can be increased through the structural adhesive, so that when the base plate is subjected to impact force, the impact force transmitted to the buffer beam can be reduced, thereby further reducing the impact force transmitted to the cylindrical battery cell, thereby further improving the safety performance of the battery.

[0014] In the preferred technical solution of the buffer beam for the cylindrical battery cell, 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 arrangement are: it is possible to 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 above-mentioned preferred technical solution of the buffer beam for cylindrical battery cells, 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.

[0017] The advantage of the above arrangement is that when the bottom wall of the rubber groove on the bottom plate is impacted upward, the boss of the shared side wall can provide deformation space for the rubber groove, thereby prolonging the action time of the force, playing a buffering effect on the impact force, and further reducing the force transmitted to the buffer beam, further protecting the battery from damage. In addition, this arrangement can also facilitate stamping of the rubber 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 present invention further provides a battery pack, which includes a accommodating cavity surrounded by side walls and a bottom plate, and 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 arranged in the gap, and the gap is filled with potting glue.

[0029] The advantage of the above arrangement is that after the potting glue is cured, each cylindrical battery cell is integrated with the buffer beam. 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 is integrated with the buffer beam, the overall structural strength of the battery can be improved. When the buffer beam receives an impact force, the structural strength of the battery is relatively high, thereby reducing the impact of the impact force on the battery, further reducing the occurrence of thermal runaway.

[0030] Solution 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 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: A buffer beam for a cylindrical battery cell according to Solution 1, characterized in that the buffer beam is a plate-like structure with a wavy shape along its length, and both side surfaces of the plate-like structure have arc surfaces corresponding to the side surfaces of the cylindrical battery cell.

[0032] Option 3: A buffer beam for a cylindrical battery cell according to Option 1 or 2, characterized in that a metal part is embedded inside at least one of the first part and the second part.

[0033] Option 4: A buffer beam for a cylindrical battery cell according to Option 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.

[0034] Option 5. A buffer beam for a cylindrical battery cell according to Option 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.

[0035] Option 6. A buffer beam for a cylindrical battery cell according to Option 1, characterized in that a cross-sectional area of ​​the end portion in the first direction is larger than a cross-sectional area of ​​the rest of the buffer beam in the first direction.

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

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

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

[0039] Option 10, a battery pack, characterized in that it 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 a buffer beam as described in any one of Options 1 to 9.

[0040] Option 11. The battery pack according to Option 10 is 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. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings, in which:

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

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

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

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

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

[0047] Figure 6 yes Figure 5 Cross-sectional view at AA in the middle;

[0048] Figure 7 It is a structural schematic diagram of the adhesive groove on the bottom plate and the buffer beam being adhesively connected to each other in the present invention;

[0049] Figure 8 1 is a schematic structural diagram of a battery pack of the present invention (I);

[0050] Fig. 92 is a schematic structural diagram of a battery pack of the present invention;

[0051] Fig.10 It is a structural schematic diagram of the protective structure of the present invention;

[0052] Fig.11 yes Fig.10 The enlarged view of point A in the middle;

[0053] Fig.12 Schematic diagram of the structure of the battery pack of the present invention (III);

[0054] Fig.13 is a partial cross-sectional view of a battery cell assembly of the present invention;

[0055] Fig.14 It is a partial structural schematic diagram of the battery cell group of the present invention;

[0056] Fig.15 yes Fig.14 Cross-sectional view at BB in the middle.

[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-reinforcement; 3-potting glue; 4-bottom plate; 41-first side; 411-boss; 412-glue groove; 42-second side; 421-groove; 5-protective structure; 51-elastic layer; 52-protective layer; 521-notch; 53-fixing piece; 54-recessed portion 6-exhaust channel. DETAILED DESCRIPTION

[0059] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the scope of protection of the present invention. Those skilled in the art can make adjustments to them as needed to adapt to specific application scenarios.

[0060] It should be noted that in the description of the present invention, terms such as "upper" and "lower" indicating directions or positional relationships are based on the directions or positional relationships 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. Therefore, it cannot be understood as a limitation on the present invention.

[0061] It should be noted that, in the description of the present invention, unless otherwise clearly specified and limited, the terms "connected" 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 invention can be understood according to the specific circumstances. In addition, in the description of the present invention, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0062] like Figures 1 to 5 As shown, in order to solve the problem of poor impact resistance of the existing battery bottom, the present invention proposes a buffer beam 2 for a cylindrical battery cell 1, the buffer beam 2 comprises a first part 21 and a second part 22 in its height direction, at least one side of the first part 21 has an arc surface corresponding to the side of the cylindrical battery cell 1, and the arc surface is connected to the side 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 arrangement, when the bottom plate 4 is impacted, since the second part 22 protrudes from the cylindrical battery cell 1, it is possible to avoid direct contact between the cylindrical battery cell 1 and the bottom plate 4 that is impacted, so that all the impact forces are concentrated on the buffer beam 2, and the impact force is transmitted from the second part 22 of the buffer beam 2 to the first part 21, and then transmitted to the side of the cylindrical battery cell 1 by the arc surface of the first part 21. Since the present invention connects the side of the cylindrical battery cell 1 with the arc surface of the buffer beam 2, it is possible to increase the connection area between the side of the cylindrical battery cell 1 and the buffer beam 2, and then reduce the impact on the cylindrical battery cell 1, thereby improving the impact resistance of the battery, reducing the possibility of thermal runaway of the battery, and protecting the battery from damage.

[0064] The present invention provides a battery pack, wherein the lower box of the battery pack includes a receiving cavity formed by a side wall and a bottom plate 4, wherein the side wall may be in a square ring shape or a circular ring shape, and the present invention does not limit its specific shape; that is, the side wall and the bottom plate 4 are formed to form a lower box, and the space in the lower box is the receiving cavity, and the lower box may be a groove-shaped structure with an open top. Furthermore, a sealing cover may be provided at the open portion, so that the sealing cover and the groove-shaped structure are formed to form a closed receiving cavity, and the lower box and the sealing cover are collectively referred to as a battery pack box.

[0065] The battery pack also includes a battery cell group, which is arranged in the receiving cavity. Possibly, the battery cell group includes a plurality of cylindrical batteries 1. When the cylindrical batteries 1 are grouped, the cylindrical batteries 1 are usually arranged in multiple rows and columns, but the present invention does not exclude the case of single-row arrangement. The battery pack of the present invention also includes a buffer beam 2, which is arranged in a height direction (such as Figure 1The cylindrical battery cell 1 includes a first portion 21 and a second portion 22 in the y direction. At least one side surface of the first portion 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 portion 21 has an arc surface corresponding to the side surface of the cylindrical battery cell 1 , that is, the first portion 21 is connected to the side surface 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 portion 21 have arc surfaces corresponding to the side surfaces of the cylindrical battery cells 1 , that is, both side surfaces of the first portion 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] A gap is formed between the sides of each adjacent cylindrical battery cell 1. In the present invention, a potting glue 3 is filled in the gap to form each cylindrical battery cell 1 as a whole. The first part 21 is arranged in the gap between adjacent cylindrical battery cells 1. The potting glue 3 can be filled in the gap of the cylindrical battery cell 1 or between the cylindrical battery cell 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 on the bottom plate 4 through the support of the buffer beam 2, that is, a gap is formed between the bottom surface 11 of each cylindrical battery cell 1 and the bottom plate 4.

[0069] Optionally, the arc surface is connected to the side of the cylindrical battery cell 1, and the arc surface and the side of the cylindrical battery cell 1 can be connected through a connector, such as the arc surface and the side of the cylindrical battery cell 1 are connected through the above-mentioned potting glue 3, or the arc surface and the side of the cylindrical battery cell 1 are welded and connected. It can be understood that the potting glue 3 of the present invention can be epoxy resin potting glue, silicone resin potting glue, polyurethane potting glue, foam 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 arrangement, when the bottom plate 4 is impacted, since each cylindrical battery cell 1 is suspended on the bottom plate 4 by the support of the buffer beam 2, it is possible to avoid direct contact between the cylindrical battery cell 1 and the bottom plate 4 that is impacted, so that all impact forces are concentrated on the buffer beam 2, and the impact force is transmitted from the second part 22 of the buffer beam 2 to the first part 21, and then transmitted to the side of the cylindrical battery cell 1 by the arc surface of the first part 21. Since the present invention connects the side of the cylindrical battery cell 1 with the arc surface of the buffer beam 2, it is possible to increase the connection area between the side of the cylindrical battery cell 1 and the buffer beam 2, and then reduce the impact on the cylindrical battery cell 1, thereby improving the impact resistance of the battery, reducing the possibility of thermal runaway of the battery, and protecting the battery from damage.

[0071] In the case where the first part 21 is disposed in the potting glue 3 in the gap between adjacent cylindrical battery cells 1, after the potting glue 3 is cured, each cylindrical battery cell 1 is integrated with the buffer beam 2. 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, thereby achieving a buffering effect and reducing the impact force on the battery. On the other hand, since each cylindrical battery cell 1 is integrated with the buffer beam 2, the overall structural strength of the battery can be improved. When the buffer beam 2 receives an impact force, the structural strength of the battery is relatively high, thereby reducing the impact of the impact force on the battery, further reducing the occurrence of thermal runaway.

[0072] Optionally, the height of the first part of the buffer beam 2 is less than the height of the battery cell, that is, the gap between the two rows of battery cells of the present invention is composed of an upper gap and a lower gap, and the first part 21 is arranged in the lower gap, and both the upper gap and the lower gap are filled with potting glue 3. In other words, the first part 21 of the present invention is not located in the entire gap, but in part of the gap. As a result, the buffer beam 2 can reduce the weight of the buffer beam 2 while providing sufficient support for the cylindrical battery cell, thereby reducing the weight of the entire battery pack. Optionally, the above-mentioned gap can form a reasonable avoidance, for example, to facilitate the cooling structure or other structures to be arranged in the upper gap. Of course, this is not restrictive, and the first part 21 of the present invention can also be located in the entire gap. These do not deviate from the principles of the present invention and are within the scope of protection of the present invention.

[0073] In one embodiment, the number of buffer beams 2 of the present invention can be set based on the number of 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 for every two rows of cylindrical battery cells 1. Of course, the number of interval cylindrical battery cells 1 is not restrictive. This arrangement, on the one hand, can stably support the battery cell group 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 provided in the gap between the two rows of cylindrical battery cells 1 between two adjacent buffer beams 2, so as to take away the heat generated during the operation of the battery pack to play a cooling role.

[0074] As a possible implementation, the buffer beam 2 is a plate-like structure that forms a wave shape along its length direction, and both sides of the plate-like structure have arc surfaces corresponding to the sides of the cylindrical battery cell 1. For example, both sides of the buffer beam 2 form a wave-like structure along the length direction, and the arc surface in the wave-like structure is the above-mentioned arc surface, that is, the wave-like structure is composed of multiple 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] The above arrangement makes it possible for the first part 21 of the buffer beam 2 to be disposed in the potting glue 3 between adjacent cylindrical cells 1, and the wavy structures on both sides are completely glued and fitted with the cylindrical cells 1. The wavy structures on the two large surfaces of the plate-like structure can increase the connection area between the buffer beam 2 and the side of the cylindrical cell 1 as much as possible, thereby increasing the force-bearing area of ​​the cylindrical cell 1 and further ensuring the safety performance of the battery. It is understandable that although the present invention is introduced with the arc surface disposed on the two side surfaces of the plate-like structure, this is not intended to limit the protection scope of the present invention. For example, the arc surface can be disposed on only one side of the plate-like structure, etc., which do not deviate from the principle of the present invention and are within the protection scope of the present invention.

[0076] The structure of the buffer beam 2 of the present invention is introduced below.

[0077] Example 1, reference Figure 5 and Figure 6 The buffer beam 2 includes a composite layer 23 and a reinforcement 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 reinforcement member 24 is embedded in the composite layer 23 in the entire length direction. The reinforcement member 24 is preferably a metal plate, specifically a high-strength steel plate, or a plastic frame, etc. The composite layer 23 may include glass fiber, resin and plastic, or a composite material containing at least two of them, etc.

[0078] Since the buffer beam 2 includes the composite layer 23 and the reinforcement 24 embedded in the composite layer 23, the structural strength of the buffer beam 2 can be improved, and the impact on the cylindrical battery cell 1 caused by the damage of the buffer beam 2 can be avoided, and the impact resistance of the cylindrical battery cell 1 can be further improved, and the possibility of thermal runaway of the battery pack can be reduced. On the other hand, when the reinforcement 24 is a metal plate, the composite layer 23 can also prevent the metal plate from corrosion and can be insulated, thereby improving the safety performance of the battery.

[0079] Furthermore, 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, a wavy structure can be formed in the length direction of the first composite layer 231 and the second composite plate. Therefore, on the basis that the buffer beam 2 is a plate-like structure to increase the connection area with the cylindrical battery cell 1, the wavy structure on the first composite layer 231 and the second composite layer 232 can further increase the connection area with the cylindrical battery cell 1, thereby further reducing the impact force on the cylindrical battery cell 1.

[0080] Example 2, reference Figure 3The buffer beam 2 is an integrally formed wave-shaped plate structure on both sides. Or the buffer beam 2 is an integrally formed wave-shaped plate structure on one side. This makes it easy to produce and shape the buffer beam 2.

[0081] Possible implementations of connecting the bottom plate 4 to the end of the buffer beam 2 are described below.

[0082] The first possible implementation is as follows: Figure 7 As shown, a glue groove 412 is formed on the bottom plate 4, and the end of the second part 22 is arranged in the glue groove 412, that is, the glue groove 412 is filled with glue, and the end of the second part 22 is arranged 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 present invention does not limit the specific shape of the glue groove 412, which is preferably a U-shaped groove, which can reduce the stress concentration at the bend and enhance the structural strength of the glue groove 412, thereby preventing it from being deformed or even broken when subjected to impact force. Of course, it can also be a V-shaped groove, etc.

[0083] Since the glue groove 412 is filled with structural glue, the present invention glues the glue groove 412 on the bottom plate 4 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 impact force, the impact force transmitted to the buffer beam 2 can be reduced, thereby further reducing the impact force transmitted to the cylindrical battery cell 1, and further improving the safety performance of the battery.

[0084] Furthermore, the cross-sectional area of ​​the adhesive groove 412 in the first direction is greater than the cross-sectional area of ​​the end of the second part 22 in the first direction. This can further increase the bonding area between the adhesive 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. The cross-sectional area of ​​the adhesive groove 412 in the first direction, that is, the horizontal area of ​​the adhesive groove 412 after the battery pack is installed, is also the horizontal cross-sectional area of ​​the end of the second part 22. Figure 7 The x direction in .

[0085] As a possible implementation, the bottom plate 4 includes a first surface 41 facing the cylindrical battery cell 1 and a second surface 42 away from the cylindrical battery cell 1 in the thickness direction, and 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 and the boss 411 share at least part of the side wall. For example, the boss 411 is located on opposite sides of the glue groove 412, and the bosses 411 on both sides share 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 is arranged opposite to the second side wall, 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 the glue groove 412 is formed in the middle of the annular boss 411. As long as the glue groove 412 and the boss 411 can share at least part of the side wall, it does not deviate from the principle of the present invention and is within the protection scope of the present invention.

[0086] The above arrangement enables the bosses 411 on both sides of the bottom wall of the glue groove 412 on the bottom plate 4 to provide deformation space for the glue groove 412 when the bottom wall is impacted upward, thereby extending the action time of the force and buffering the impact force, thereby reducing the force transmitted to the buffer beam 2 and further protecting the battery from damage. In addition, this arrangement can also facilitate stamping of the glue groove 412.

[0087] A second possible implementation method, referring to Figure 1 The cross-sectional area of ​​the end of the second portion 22 in the first direction is greater than the cross-sectional area of ​​the rest of the buffer beam 2 in the first direction. The first direction refers to the horizontal direction after the battery pack is installed. Figure 1 The x direction of the buffer beam 2. Figure 1 The cross section of the second portion 22 (in the y direction) is preferably in an inverted T shape, and the end of the second portion 22 may be a plate-like structure with a cross section larger than the cross section of the remaining portion. Furthermore, the end of the second portion 22 may be bonded to the bottom plate 4 by structural adhesive, thereby improving the connection strength between the buffer beam 2 and the bottom plate 4, making them integral, and further improving the impact resistance. Less preferably, the end of the second portion 22 may be connected to the bottom plate 4 by screw connection or riveting.

[0088] Since the cross-sectional area of ​​the end of the second portion 22 in the first direction is larger than the cross-sectional area of ​​the remaining portion 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, thereby reducing the impact force transmitted to the buffer beam 2, and further reducing the force transmitted to the cylindrical battery cell 1, further improving the safety performance of the cylindrical battery cell 1.

[0089] Among them, the two possible implementations of connecting the bottom plate 4 and the end of the buffer beam 2 introduced above can be used interchangeably or cross-coordinated to form new implementations. These simple changes do not deviate from the principles of the present invention and are within the scope of protection of the present invention.

[0090] In the above embodiment, since each cylindrical battery cell 1 is suspended on the bottom plate 4 by the support of the buffer beam 2, the bottom surface 11 of each cylindrical battery cell 1 is out of the protection of the bottom plate 4. If a cylindrical battery cell 1 has thermal runaway, the explosion-proof valve at the bottom of the cylindrical battery cell 1 will open, which can easily affect the bottom surface 11 of other cylindrical battery cells 1, thus easily causing thermal runaway of the entire battery pack. In order to avoid this phenomenon, Figures 8 to 15 As shown, the battery pack of the present invention also includes a protective structure 5, and the protective structure 5 includes a protective layer 52. The protective layer 52 is arranged on the bottom side of the battery cell group, and a weak area is provided on the protective layer 52, and the weak area corresponds to the explosion-proof valve of some or all of the cylindrical batteries 1 in the battery cell group. Among them, the bottom surface 11 of each cylindrical battery cell 1 can be provided with an explosion-proof valve. The protective layer 52 of the present invention can be covered on each bottom surface 11 and each explosion-proof valve, and the protective 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 location of the negative electrode of the cylindrical battery cell 1. When the cylindrical battery cells 1 are grouped, the bottom surface 11 of the cylindrical battery cells 1 are all located on the bottom side of the battery cell group.

[0091] The above-mentioned arrangement ensures that when thermal runaway occurs in one or some cylindrical battery cells 1, the explosion-proof valve on the bottom surface 11 of the cylindrical battery cell 1 that has thermal runaway will open. Since the protective layer 52 is provided with a weak area at the position corresponding to the explosion-proof valve, the weak area will be opened after the explosion-proof valve is opened, that is, high-temperature gas, sparks and high-temperature solid particles will erupt through the weak area. Since the bottom of other cylindrical battery cells 1 are protected by the protective layer 52, they will not be affected by the eruption or will be less affected by the eruption, thereby being able to play a role in safety protection.

[0092] The specific forms of the weak area of ​​the present invention include various types. For example, the protective 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 flushed when the explosion-proof valve is opened. Alternatively, the weak area is a notch 521, so that after the explosion-proof valve is opened, the corresponding part of the protective layer 52 will be flushed along the notch 521. As long as the weak area can be flushed after the explosion-proof valve is opened, the specific form of the weak area can be adjusted.

[0093] Preferably, the protective layer 52 can be insulated, for example, the protective layer 52 is a high temperature resistant material such as mica or ceramic, which can insulate other cylindrical cells 1 when the explosion-proof valve is opened, and can also play a role in high voltage safety protection.

[0094] As a possible implementation, the shape of the weak zone 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 zone is also circular, thereby minimizing the penetration area of ​​the protective layer 52 and concentrating the penetration at the explosion-proof valve, thereby reducing the possibility of erosion of other cylindrical battery cells 1. Furthermore, the number of weak zones can be multiple, and each weak zone corresponds to the position of each explosion-proof valve one by one. This makes it easy for the high-temperature gas, sparks and high-temperature solid particles generated after any explosion-proof valve is opened to be ejected from the corresponding weak zone, avoiding affecting adjacent batteries.

[0095] As a possible implementation method, refer to Figure 1 and Figure 4 An exhaust channel 6 is formed between two adjacent buffer beams 2, the bottom plate 4 and the protective layer 52. In this arrangement, when the protective layer 52 of a cylindrical battery cell 1 is broken due to thermal runaway, harmful hot gas will flow through the exhaust channel 6, and the protective layer 52 can prevent the harmful hot gas from corroding the cylindrical battery cell 1 between the two adjacent buffer beams 2.

[0096] As a possible implementation, the protective structure 5 also 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 or the like. 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 contour tolerance of the bottom surface 11 of the cylindrical battery cell 1 group can be absorbed by the elastic layer 51. When the glue is poured, the battery cell group will be turned upside down for glue pouring, so that the glue pouring tooling can fit tightly with the battery cell group, thereby preventing the potting glue 3 from leaking to the explosion-proof valve of the cylindrical battery cell 1, which would hinder 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, which connects the protective layer 52 and the elastic layer 51. This prevents the elastic layer 51 and the protective layer 52 from being delaminated and falling off. The number of the fixing members 53 can be multiple, for example, 8, etc., which can be evenly spaced and distributed on the protective structure 5. The specific structural forms of the fixing members 53 include various, for example, the fixing members 53 are plastic buckles or screws.

[0098] There are many ways to connect the bottom of the battery cell group and the protection structure 5.

[0099] In a 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, the potting glue 3 in the gap is solidified and the fixing member 53 is locked, thereby connecting the protective structure 5 and the cylindrical battery cell 1 module.

[0100] In a second possible implementation manner, the battery cell group and the elastic layer 51 are bonded together by filling the gaps between adjacent cylindrical battery cells 1 with a potting adhesive 3 .

[0101] Possibly, the protective structure 5 of the present invention can be multi-segmented or can be a whole. In the case where the protective structure 5 is multi-segmented, a buffer beam 2 can be disposed between two adjacent sections of the protective structure 5. For example, in the case where a buffer beam 2 is disposed for every two cylindrical battery cells 1, a section of the protective structure 5 is disposed on the bottom cover of every two cylindrical battery cells 1, and the buffer beam 2 is disposed between the two sections of the protective structure 5, thereby avoiding the buffer beam 2 from interfering with the protective structure 5 and affecting the performance of the protective structure 5. In the case where the protective structure 5 is a whole, the buffer beam 2 can pass through the protective structure 5 and then be fixed in the potting glue 3 in the gap between the adjacent cylindrical battery cells 1. As long as the protective structure 5 can be covered at the bottom of each cylindrical battery cell 1, it does not deviate from the principle of the present invention and is within the protection scope of the present invention.

[0102] As a possible implementation method, refer to Fig.15 The edge of the protective structure 5 of the present invention includes a recessed portion 54 that is recessed toward the gap between adjacent cylindrical cells 1. The recessed portion 54 may be arc-shaped. Since a gap is formed between adjacent cylindrical cells 1, the present invention can reasonably utilize the space at the gap by forming a recessed portion 54 that is recessed toward the gap at the edge of the protective structure 5, thereby reducing the volume of the protective structure 5, reducing the space occupied by the protective structure 5, and thus improving the energy density of the battery.

[0103] Furthermore, the edge of the protective structure 5 includes a plurality of recessed portions 54, each recessed portion 54 corresponds to each gap one by one, and is recessed into each gap. For example, the battery cell group includes a whole row of first battery cell groups located on one side in the width direction thereof, and also includes a whole row of second battery cell groups located on the other side in the width direction thereof. The protective structure 5 covers the first battery cell group, the second battery cell group, and the battery cell group between the first battery cell group and the second battery cell group (if any), and the protective structure 5 is formed with a recessed portion 54 recessed into each gap of the first battery cell group at the edge near the first battery cell group, and the protective structure 5 is formed with a recessed portion 54 recessed into each gap of the second battery cell group at the edge near the second battery cell group. In this way, the space at the gap can be utilized as much as possible, the volume of the protective structure 5 can be further reduced, and the energy density of the battery can be further improved.

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

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

[0106] So far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, 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 invention.

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.

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