Battery monomer, battery device and electric equipment

Abstract

The invention discloses a single battery, a battery device and electric equipment, and relates to the technical field of batteries, the single battery comprises a shell and at least one battery cell, and the shell forms a mounting cavity; the battery cell is arranged in the mounting cavity, the peripheral side of the battery cell comprises two large surfaces which are oppositely arranged, two corner surfaces which are oppositely arranged and transition areas between the large surfaces and the corner surfaces, and the shell comprises two first cavity wall surfaces which are oppositely arranged and two second cavity wall surfaces which are oppositely arranged; a buffer cushion layer is arranged between at least one large surface and the first cavity wall surface, the buffer cushion layer is a first buffer cushion layer, the thickness of the first buffer cushion layer is gradually increased in the direction from the middle of the large surface to any corner surface, and / or a buffer cushion layer is arranged at least partially between two adjacent battery cells, the buffer cushion layer is a third buffer cushion layer, and the thickness of the third buffer cushion layer is gradually increased in the direction from the middle of the large surface to any corner surface. And in the direction from the large surface to any corner surface, the thickness of the third buffer cushion layer is gradually increased. According to the battery monomer, the cracking risk of the battery cell can be reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and in particular to a battery cell, a battery device and an electrical equipment. Background Art

[0002] During the use of the battery, the active layer of the electrode of the battery cell will expand. Due to the characteristics of the battery's own winding structure, the risk of cracking of the outermost positive and negative electrodes is relatively high, which affects the service life of the battery. Summary of the invention

[0003] The main purpose of the present invention is to provide a battery cell, aiming to solve the technical problem that the pole piece in the battery cell is easy to crack.

[0004] To achieve the above-mentioned purpose, the battery cell proposed by the present invention comprises: a housing forming a mounting cavity; and At least one battery cell is arranged in the installation cavity, the peripheral side of the battery cell includes two relatively large surfaces and two relatively corner surfaces, and a transition zone between the large surfaces and the corner surfaces, and the shell includes two relatively first cavity wall surfaces and two relatively second cavity wall surfaces; the buffer pad layer is arranged between at least one of the large surfaces and the first cavity wall surfaces, and the buffer pad layer is arranged as a first buffer pad layer, and the thickness of the first buffer pad layer increases in the direction from the middle of the large surface to any of the corner surfaces; and / or, a buffer pad layer is arranged at least partially between two adjacent battery cells; the buffer pad layer between two adjacent battery cells is a third buffer pad layer, and the thickness of the third buffer pad layer increases in the direction from the middle of the large surface to any of the corner surfaces.

[0005] In the battery cell structure, a first buffer layer is set between a large surface and the first cavity wall, or between each large surface and each first cavity wall, so that the buffer layer can increase the lateral resistance of the large surface and the corner surface after the battery cell pole piece expands, constrain the pole piece to move in the lateral direction, reduce the expansion force, and provide a buffer for the pole piece after expansion, so that the expansion force is evenly dispersed to the first buffer layer, reducing stress concentration and reducing the risk of pole piece fracture. The first buffer layer of the structure can reduce the thickness of the structure corresponding to the middle position of the large surface, thereby reducing the impact on the group margin of the battery cell; and provide expansion space in the middle of the large surface to avoid the deterioration of the expansion force, while constraining the lateral movement of the pole piece at the edge position after expansion, reducing the consumption of the elongation rate of the corner pole piece fracture.

[0006] Or when two cells are included, a buffer layer is provided at part or all of the positions between the two cells. The deformation of the buffer layer can provide a certain expansion space to avoid the deterioration of the expansion force of the battery cell; and the buffering of the buffer layer can reduce the friction between the cell and the shell, and also avoid the contact between the two cells to produce stress concentration, reduce the risk of cracking of the pole piece, especially the cracking risk of the outermost pole piece, and improve the performance of the battery cell. The third buffer layer of this structure can reduce the thickness of the structure corresponding to the middle position of the large surface, thereby reducing the impact on the group margin of the battery cell; and provide expansion space in the middle of the large surface, avoid the deterioration of the expansion force, and restrain the lateral movement of the pole piece at the edge position after expansion, reducing the consumption of the fracture elongation rate of the corner pole piece.

[0007] In one embodiment of the present invention, at least the transition zone is provided with the buffer layer.

[0008] In one embodiment of the present invention, the surface of the buffer layer facing the transition zone is a plane or a curved surface.

[0009] In one embodiment of the present invention, an extension length of the first buffer layer is the same as an extension length of the first cavity wall.

[0010] The first buffer layer of this structure can not only isolate the entire large surface from the first cavity wall, but also isolate part of the corner surface connected to the large surface from the first cavity wall. While restraining the expansion of the large surface of the battery cell, it can further reduce the friction between the pole piece and the shell, further reducing the risk of cracking.

[0011] In one embodiment of the present invention, a buffer layer is provided between at least one of the corner surfaces and the second cavity wall surface, and the buffer layer is configured as a second buffer layer.

[0012] The battery cell of this structure not only protects the large surface, but also protects the corner surface, providing a certain buffer for the expansion of the pole piece at the corner surface and reducing the risk of cracking of the top shell of the corner surface.

[0013] In one embodiment of the present invention, the second buffer layer is in the shape of a flat plate, and an extension width of the second buffer layer is the same as an extension width of the second cavity wall.

[0014] The second buffer layer increases the buffer area of ​​the corner surface of the battery cell, improves protection, and facilitates processing.

[0015] In an embodiment of the present invention, a surface of the second buffer layer facing the corner surface is a curved surface, and the curvature of the curved surface is less than or equal to the curvature of the corner surface.

[0016] The second buffer layer of the structure can increase the restraint on the expansion of the corner surface and reduce the risk of fracture of the top shell of the corner surface.

[0017] In one embodiment of the present invention, a surface of the second buffer layer away from the corner surface is a curved surface, and the second buffer layer is in the shape of a curved plate with uniform thickness.

[0018] The second buffer layer of this structure is easy to process and reduces the impact on the margin of the battery cell group.

[0019] In one embodiment of the present invention, a surface of the second buffer layer facing away from the corner surface is a plane.

[0020] The second cushion layer of the structure is easy to install.

[0021] In one embodiment of the present invention, the thickness of the first buffer layer gradually increases in a direction from the middle of the large surface to any one of the corner surfaces.

[0022] The first buffer layer of the structure can reduce the sharp part and avoid the risk of cracking caused by stress concentration.

[0023] In one embodiment of the present invention, the minimum thickness of the first buffer layer is d1, and the maximum thickness of the first buffer layer is d2, wherein the range of d1 / d2 is greater than or equal to 10% and less than or equal to 50%.

[0024] The first buffer layer within this ratio range can achieve a better anti-cracking effect.

[0025] In an embodiment of the present invention, the cushion layer is made of rubber or sponge.

[0026] This material has good compressibility and low cost, and improves the cushioning effect of the cushion layer.

[0027] In one embodiment of the present invention, the compression rate of the buffer layer is greater than or equal to 75%.

[0028] The buffer layer can have a large compression space, providing a large expansion space for the battery cell, reducing cracking while avoiding deterioration of expansion force.

[0029] In one embodiment of the present invention, the thickness of the buffer layer is d3, and the thickness of the battery cell is d4, wherein the range of d3 / d4 is greater than or equal to 2% and less than or equal to 15%.

[0030] The buffer layer of this structure has a certain buffering effect and a small thickness, and has little effect on the group margin of the battery cell.

[0031] The present invention further provides a battery device, comprising any of the battery cells described above.

[0032] The present invention also provides an electrical device, comprising the battery device as described above. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0034] Figure 1 It is a structural schematic diagram of the electrical equipment of the present invention; Figure 2 A partial exploded view of the battery device of the present invention; Figure 3 It is a schematic structural diagram of a first embodiment of a battery cell of the present invention; Figure 4 It is a structural schematic diagram of a second embodiment of a battery cell of the present invention; Figure 5 It is a schematic structural diagram of a third embodiment of a battery cell of the present invention; Figure 6 It is a schematic structural diagram of a fourth embodiment of a battery cell of the present invention; Figure 7 It is a schematic structural diagram of a fifth embodiment of a battery cell of the present invention; Figure 8 It is a schematic structural diagram of a sixth embodiment of a battery cell of the present invention; Fig. 9 It is a structural schematic diagram of a seventh embodiment of a battery cell of the present invention; Fig.10 It is a schematic structural diagram of an eighth embodiment of a battery cell of the present invention; Fig.11 It is a schematic structural diagram of a ninth embodiment of a battery cell of the present invention; Fig.12 It is a schematic structural diagram of a tenth embodiment of a battery cell of the present invention; Fig.13 It is a schematic structural diagram of the eleventh embodiment of a battery cell of the present invention.

[0035] Description of Figure Numbers: 100, battery device; 10, housing; 11, first part; 12, second part; 20, battery cell; 21, housing; 21a, mounting cavity; 211, first cavity wall; 212, second cavity wall; 22, battery cell; 221, large surface; 222, corner surface; 231, first buffer layer; 232, second buffer layer; 233, third buffer layer; 200, controller; 300, motor.

[0036] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0037] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0039] In the present invention, unless otherwise clearly specified and limited, the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0040] In addition, the descriptions of "first", "second", etc. in the present invention are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the meaning of "and / or" appearing in the full text is to include three parallel solutions. Taking "A and / or B as an example", it includes solution A, or solution B, or a solution that satisfies both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0041] The battery devices mentioned in the art can be divided into disposable batteries and rechargeable batteries according to whether they are rechargeable. The common types of rechargeable batteries currently include: lead-acid batteries, nickel-metal hydride batteries and lithium-ion batteries. The battery device described in the embodiments of the present invention refers to a rechargeable battery. The embodiments disclosed in the present invention will be described below mainly using lithium-ion batteries as an example. It should be understood that the embodiments disclosed in the present invention are applicable to any other appropriate type of rechargeable battery. The battery device mentioned in the embodiments disclosed in the present invention can be directly or indirectly applied to an appropriate device to power the device.

[0042] The battery device mentioned in the embodiments disclosed in the present invention refers to a single physical module including one or more battery cells to provide a predetermined voltage and capacity, which can be a battery module or a battery pack. The battery cell is the basic unit in the battery device, which can be used to make a battery module or a battery pack. The battery module is formed by connecting a certain number of battery cells in series and / or in parallel and placing them in a frame in order to protect the battery cells from external impact, heat, vibration, etc. The battery pack generally includes a battery module, a battery management system, and a box that accommodates the battery module and the battery management system. The battery management system is used to monitor and manage the charging and discharging process of the battery module.

[0043] The battery cell is an important component of the battery monomer. According to the preparation method of the battery cell, it can be divided into a wound battery cell and a laminated battery cell. Among them, the wound battery cell is widely used because it is relatively simple to operate and the quality is easy to control. The wound battery cell generally includes a negative electrode sheet, a positive electrode sheet and a separator arranged and wound in a preset order. The positive electrode sheet and the negative electrode sheet are generally composed of a current collector and an active material layer coated on the current collector, respectively. The wound battery cell can be a square structure or a cylindrical structure. Among them, the square wound battery cell is widely used due to its advantages such as good heat dissipation.

[0044] As the temperature of the battery cell increases during use, the active material layer on each pole piece in the wound battery cell will expand due to the temperature increase, and then exert an outward expansion force on the corresponding part wrapped outside it, such as the pole piece located in the outer ring. In addition, as the expansion continues, the outer wall of the pole piece in the battery cell will contact and squeeze the inner wall of the shell (for ease of description, this phenomenon is referred to as the top shell below), so that the pole piece will receive the pressure applied to it by the shell, and at the same time, the pole piece located in the outer ring of the battery cell will also come into frictional contact with the shell during the expansion process, thereby receiving friction from the shell.

[0045] At this time, due to the characteristics of the winding structure of the square wound electrode assembly, the electrode pieces located on the outer circle will be subject to outward pressure exerted by the inner circle electrode pieces due to the expansion of the active material layer. After the large surface of the battery cell hits the top shell, the expansion force of the electrode pieces located in the corner transition zone of the outer circle continues to increase, which will generate friction with the shell. Under the combined action of expansion force and friction, there is a stress concentration phenomenon, which is very likely to crack, thereby causing the battery performance to decline and affecting the battery life.

[0046] Based on the above background, the present invention proposes a battery cell. By improving the battery cell and setting a buffer layer between the battery cell and the shell, expansion space and buffering effect of the battery cell can be provided, thereby reducing the risk of cracking of the pole piece top shell.

[0047] The battery device disclosed in the embodiment of the present application can be used in various energy storage systems that use batteries as power sources or use batteries as energy storage elements. The electrical equipment can be, but is not limited to, mobile phones, tablets, laptops, electric toys, electric tools, battery cars, electric cars, ships, spacecraft, etc. Among them, electric toys can include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc., and spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0048] For the convenience of explanation, the following examples are referred to Figure 1 , an electrical device in one embodiment of the present application is taken as an example of a vehicle.

[0049] Figure 1 The electrical equipment provided for some embodiments of the present application is a schematic diagram of the structure of a vehicle. The vehicle may be a fuel vehicle, a gas vehicle or a new energy vehicle, and the new energy vehicle may be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. A battery device 100 is provided inside the vehicle, and the battery device 100 may be provided at the bottom, head or tail of the vehicle. The battery device 100 may be used to power the vehicle, for example, the battery device 100 may be used as an operating power source for the vehicle. The vehicle may also include a controller 200 and a motor 300, and the controller 200 is used to control the battery device 100 to power the motor 300, for example, for starting, navigating and driving the vehicle.

[0050] In some embodiments of the present application, the battery device 100 can be used not only as an operating power source for the vehicle, but also as a driving power source for the vehicle, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle.

[0051] refer to Figure 2 , Figure 2An exploded view of a battery device 100 provided in some embodiments of the present application. The battery device 100 includes a box 10 and at least two battery cells 20, wherein the box 10 is used to provide a storage space for the battery cells 20, and the box 10 can adopt a variety of structures. In some embodiments, the box 10 may include a first part 11 and a second part 12, the first part 11 and the second part 12 cover each other, and the first part 11 and the second part 12 jointly define a storage space. The second part 12 may be a hollow structure with one end open, the first part 11 may be a plate-like structure, and the first part 11 covers the open side of the second part 12, so that the first part 11 and the second part 12 jointly define a storage space; the first part 11 and the second part 12 may also be hollow structures with one side open, and the open side of the first part 11 covers the open side of the second part 12. Of course, the box 10 formed by the first part 11 and the second part 12 may be in a variety of shapes, such as a cylinder, a cuboid, etc.

[0052] In the battery device 100, there may be a plurality of battery cells 20, which may be connected in series, in parallel, or in mixed series to form a whole and accommodated in the box 10. Mixed series means that the plurality of battery cells 20 are both connected in series and in parallel. The battery device 100 may also include other structures, for example, a busbar component for realizing electrical connection between the plurality of battery cells 20.

[0053] The battery cell 20 may be a secondary battery or a primary battery, or a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, etc. The battery cell 20 may be cylindrical, flat, rectangular, or in other shapes.

[0054] In some cases, the battery cell 20 can also be directly installed in the vehicle without the box body 10 , that is, there is no need to form a battery pack, and the structure of the vehicle body itself serves as a fixing structure for the battery cell 20 .

[0055] The battery cell 20 of the present application is introduced below with a specific embodiment: Please refer to Figures 3 to 13 In one embodiment of the present invention, the battery cell 20 includes: a housing 21 forming a mounting cavity 21a; and At least one battery cell 22, the battery cell 22 is arranged in the installation cavity 21a, the peripheral side of the battery cell 22 includes two relatively arranged large surfaces 221 and two relatively arranged corner surfaces 222, and a transition zone between the large surfaces 221 and the corner surfaces 222, the shell 21 includes two relatively arranged first cavity wall surfaces 211 and two relatively arranged second cavity wall surfaces 212; the buffer layer is arranged between at least one of the large surfaces 221 and the first cavity wall surface 211, and the buffer layer is set as a first buffer layer 231; in the direction from the middle of the large surface 221 to any of the corner surfaces 222, the thickness of the first buffer layer 231 increases progressively; And / or, a buffer layer is provided at least partially between two adjacent battery cells 22, and the buffer layer between two adjacent battery cells 22 is a third buffer layer 233, and the thickness of the third buffer layer 233 increases in the direction from the middle of the large surface 221 to any corner surface 222.

[0056] In this embodiment, the battery cell 20 includes a shell 21 and an electrode assembly. The shell 21 is a closed structure, forming a mounting cavity 21a required for the battery cell 22. The shell 21 generally includes an end cover and a shell body. The shell body is formed with a receiving groove with an opening. The battery cell 22 is installed in the receiving groove, and the end cover is closed on the opening to form the mounting cavity 21a. The specific structure of the end cover and other functional components arranged thereon can refer to the existing end cover structure, and will not be described in detail here. Of course, electrolyte and other components are also arranged in the shell 21, which will not be described in detail here.

[0057] One, two or more battery cells 22 may be provided in a battery cell 20. The battery cell 22 is formed by winding an electrode assembly, which includes a separator and at least two electrode sheets. The at least two electrode sheets refer to at least one positive electrode sheet and one negative electrode sheet, which are generally stacked in the order of positive electrode sheet, separator, negative electrode sheet, separator, or negative electrode sheet, separator, positive electrode sheet, separator. When the electrode assembly includes multiple negative electrode sheets and multiple positive electrode sheets, the stacking principle is equivalent to the above, which will not be described in detail here.

[0058] In one example, after the positive electrode sheet, the negative electrode sheet and the separator are stacked and wound in a preset order, a flat multi-turn winding body is formed. The innermost circle of the electrode sheet is composed of two sheets bonded together. Except for the electrode sheet portion located in the innermost circle, the electrode sheet portion of each other circle includes two oppositely arranged straight portions and two curved portions connecting the two straight portions. It should be noted that the outermost circle refers to the outermost circle of the electrode assembly after winding, that is, the electrode sheet portion that is not wrapped inside and exposed. One curved portion in the outermost circle of the electrode sheet connects the two straight portions in the circle, and the other curved portion connects a straight portion of the circle and a straight portion of another adjacent circle.

[0059] The circumferential side of the battery cell 22 refers to the side surface of the battery cell 22 in the winding direction, that is, it includes the surface of the straight portion and the surface of the curved portion. The two large surfaces 221 refer to the surfaces of the two straight portions facing the shell 21, and the two corner surfaces 222 refer to the surfaces of the two curved portions facing the shell 21. The two large surfaces 221 and the two corner surfaces 222 are connected alternately in sequence, and the transition zone refers to the surface at the transition position where the large surface 221 and the corner surface 222 are connected. The cavity wall of the installation cavity 21a refers to the cavity side wall, that is, the side wall in the height direction of the battery cell 20. The inner surface of the shell 21 is two first cavity wall surfaces 211 and two second cavity wall surfaces 212. The shell 21 is roughly rectangular, so the two first cavity wall surfaces 211 correspond to the two large surfaces 221, and the two second cavity wall surfaces 212 correspond to at least two corner surfaces 222.

[0060] The cushion layer refers to a layered, sheet-like, plate-like or block-like structure that can be deformed and has a cushioning function, such as a cushion structure of a flexible or elastic material, or a hard structure that can be elastically deformed, which is not limited here. The thickness of the cushion layer can be uniform or uneven, which is not limited here.

[0061] In order to distinguish, the buffer layer between the large surface 221 and the first cavity wall surface 211 is defined as the first buffer layer 231. Taking the battery cell 22 as an example, the first buffer layer 231 is arranged between at least one large surface 221 and the first cavity wall surface 211, which means that the first buffer layer 231 is arranged between one of the large surfaces 221 of the battery cell 22 and the corresponding first cavity wall surface 211, or the first buffer layer 231 is arranged between the two large surfaces 221 of the battery cell 22 and the two corresponding first cavity wall surfaces 211. In one example, the size of the first buffer layer 231 in the height direction of the battery cell 22 is the same as the height of the battery cell 22, and the size of the first buffer layer 231 in the winding direction is the same as the length of the large surface 221, so that the protection area can be increased. In other examples, the size of the first buffer layer 231 in the height direction can also be smaller than the height of the battery cell 22, and the size of the first buffer layer 231 in the winding direction is smaller than the length of the large surface 221. For example, the first buffer layer 231 is provided on only a part of the surface of the straight portion, the entire surface of the straight portion, or a transition area where the straight portion and the curved portion meet.

[0062] Since the shell 21 and the large surface 221 of the battery cell 22 are closely attached, and the large surface 221 has a greater expansion capacity, the battery cell 20 of this structure is provided with a first buffer layer 231 between a large surface 221 and the first cavity wall 211, or a first buffer layer 231 is provided between each large surface 221 and each first cavity wall 211, so that the buffer layer can increase the lateral resistance of the large surface 221 and the corner surface 222 after the pole piece of the battery cell 22 expands, constrain the pole piece to stretch and move in the lateral direction, and reduce the expansion force; at the same time, it provides a buffer for the pole piece after expansion, so that the expansion force is evenly dispersed to the first buffer layer 231, and the friction force is reduced, the stress concentration is reduced, and the risk of pole piece fracture is reduced.

[0063] A first buffer layer 231 is provided between the large surface 221 and the first cavity wall surface 211, and the thickness of the first buffer layer 231 is unevenly provided. Specifically, the middle of the large surface 221 refers to the middle of the large surface 221 in the length direction of the battery cell 22, and the thickness of the first buffer layer 231 increases in the direction from the middle of the large surface 221 to a corner surface 222, that is, in the direction from the middle of the battery cell 22 in the length direction to the two edges thereof, for example, gradually increases, or increases in a step-like manner. This also makes the thickness of the first buffer layer 231 corresponding to the large surface 221 in the middle of the length direction small, and the thickness close to the edge position is large.

[0064] The first buffer layer 231 of this structure can reduce the thickness of the structure corresponding to the middle position of the large surface 221, thereby reducing the impact on the group margin of the battery cell 20; and provide expansion space in the middle of the large surface 221 to avoid the deterioration of the expansion force, while restraining the lateral movement of the pole piece at the edge position after expansion, reducing the consumption of the elongation rate of the corner pole piece at break.

[0065] On the basis of limiting or not limiting that a buffer layer is provided between at least one large surface 221 of the battery cell 22 and the first cavity wall surface 211 and the thickness of the buffer layer varies, when at least two battery cells 22 are provided, at least two battery cells 22 are arranged side by side, and the two adjacent battery cells 22 are arranged with the straight portions facing each other. A buffer layer is provided at least partially between two adjacent battery cells 22, and the buffer layer is a third buffer layer 233, that is, the third buffer layer 233 is located at least partially between the two straight portions of the two battery cells 22. The dimension of the third buffer layer 233 in the length direction may be less than, equal to or greater than the length of the straight portion of the battery cell 22, which is not limited here. The dimension of the third buffer layer 233 in the height direction may be the same as the height of the battery cell 22, thereby increasing the protection area. In one example, the dimension of the third buffer layer 233 in the length direction is the same as the length of the shell 21. The deformation of the third buffer layer 233 can provide a certain expansion space to avoid the deterioration of the expansion force of the battery cell 20; and the buffering of the third buffer layer 233 can reduce the friction between the battery cell 22 and the shell 21, and avoid stress concentration caused by contact between the two battery cells 22, thereby reducing the risk of cracking of the pole piece, especially the risk of cracking of the outermost pole piece, and improving the performance of the battery cell 20.

[0066] The thickness of the third buffer layer 233 corresponding to the large surface 221 in the middle of the length direction is small, and the thickness near the edge is large. The third buffer layer 233 of this structure can reduce the thickness of the structure corresponding to the middle position of the large surface 221, thereby reducing the impact on the group margin of the battery cell 20; and provide expansion space in the middle of the large surface 221 to avoid the deterioration of the expansion force, while restraining the lateral movement of the pole piece at the edge position after expansion, reducing the consumption of the fracture elongation rate of the corner pole piece.

[0067] Optionally, the buffer pad layer is disposed on the peripheral side surface of the battery cell 22, with a gap between it and the cavity wall of the installation cavity 21a; or, the buffer pad layer is disposed on the cavity wall of the installation cavity 21a, with a gap between it and the peripheral side surface of the battery cell 22; or, there is a gap between the buffer pad layer and both the peripheral side surface of the battery cell 22 and the cavity wall of the installation cavity 21a; or, the buffer pad layer respectively abuts against the peripheral side surface of the battery cell 22 and the cavity wall of the installation cavity 21a, which is not limited here.

[0068] In the structure of the battery cell 20, the battery cell 22 is assembled in the shell 21, and a buffer layer is provided between at least one large surface 221 of the battery cell 22 and the cavity wall of the installation cavity 21a, and / or a buffer layer is provided at a part or all of the positions between two adjacent battery cells 22. The deformation of the buffer layer can provide a certain expansion space to avoid the deterioration of the expansion force of the battery cell 20; and the buffering of the buffer layer can reduce the friction between the battery cell 22 and the shell 21, and / or avoid stress concentration caused by contact between the two battery cells 22, reduce the risk of cracking of the pole piece, especially the risk of cracking of the outermost pole piece, improve the performance of the battery cell 20, and extend the service life.

[0069] In one embodiment of the present invention, at least the transition zone is provided with a buffer layer.

[0070] In the present embodiment, the transition zone includes part of the plane and part of the curved surface, which is the position where the stress on the battery cell 22 is most concentrated. Therefore, a buffer layer is provided in the transition zone. The buffer layer can buffer and disperse the friction and expansion force between the transition zone and the first cavity wall 211 after the pole piece of the battery cell 22 expands, thereby reducing stress concentration and reducing the risk of pole piece breakage to the greatest extent and at the lowest cost.

[0071] In one embodiment of the present invention, the surface of the buffer layer facing the transition zone is a plane or a curved surface.

[0072] In one example, the surface of the buffer layer facing the transition zone is flat. The buffer layer of this structure is convenient for processing and assembly, and provides a certain buffering force when the transition zone expands, thereby reducing the risk of fracture of the top shell of the transition zone.

[0073] In another example, the surface of the cushion layer facing the transition zone is a curved surface, which can be a circular arc surface or a non-circular arc surface, which is not limited here. The cushion layer of this structure can increase the restraint on the expansion of the transition zone and provide a buffer force, thereby reducing the risk of the top shell of the transition zone breaking. The curvature of the curved surface is less than or equal to the curvature of the corner surface 222, so that the transition zone will not be squeezed too much on the basis of reducing the distance between the transition zone and the cushion layer.

[0074] Please continue to refer to Figure 3 In one embodiment of the present invention, the extension length of the first buffer layer 231 is the same as the extension length of the first cavity wall 211 .

[0075] In this embodiment, taking the battery cell 20 as a rectangular parallelepiped as an example, the line between the two corner surfaces 222 is the length direction of the shell 21, the extension length of the first buffer layer 231 refers to the dimension of the first buffer layer 231 extending in the length direction of the shell 21, and the extension length of the first cavity wall 211 refers to its length in the length direction of the shell 21. The extension length of the first buffer layer 231 is the same as the extension length of the first cavity wall 211, which means that the two ends of the first buffer layer 231 extend toward the two second cavity wall surfaces 212 and abut against the second cavity wall surfaces 212. In one example, the first buffer layer 231 is planar, and there is a large gap between part of the corner surface 222 and the first cavity wall surface 211. In other examples, the first buffer layer 231 may also be curved in the portion corresponding to the corner surface 222.

[0076] The first buffer layer 231 of this structure can not only isolate the entire large surface 221 from the first cavity wall 211, but also isolate the transition zone from the first cavity wall 211. While restraining the expansion of the large surface 221 of the battery cell 22, it can further reduce the friction between the pole piece and the shell 21, further reducing the risk of cracking.

[0077] Please refer to Figure 4 and Figure 6 In one embodiment of the present invention, a buffer layer is provided between at least one of the corner surfaces 222 and the second cavity wall surface 212 , and the buffer layer is configured as a second buffer layer 232 .

[0078] In this embodiment, on the basis of providing the first buffer layer 231, a second buffer layer 232 is provided between at least one corner surface 222 and the second cavity wall surface 212, which means that a second buffer layer 232 is provided between one of the corner surfaces 222 and the second cavity wall surface 212, or a second buffer layer 232 is provided between two corner surfaces 222 and two cavity wall surfaces. In one example, the dimension of the second buffer layer 232 in the height direction of the battery cell 22 is the same as the height of the battery cell 22, so that the protection area can be increased. In other examples, the dimension of the second buffer layer 232 in the height direction of the battery cell 22 can also be smaller than the dimension of the second cavity wall surface 212 in the height direction of the battery cell 22. In other examples, the second buffer layer 232 can also be provided without providing the first buffer layer 231, such as Figure 7 shown.

[0079] The battery cell 20 of this structure not only protects the large surface 221 , but also protects the corner surface 222 , thereby providing a certain buffer for the expansion of the pole piece at the corner surface 222 and reducing the risk of cracking of the top shell of the corner surface 222 .

[0080] Please continue to refer to Figure 4In one embodiment of the present invention, the second buffer layer 232 is in the shape of a flat plate, and the extension width of the second buffer layer 232 is the same as the extension width of the second cavity wall 212 .

[0081] In this example, the connection direction of the two large surfaces 221 of a battery cell 22 is the width direction of the battery cell 22, and the second buffer layer 232 is in the shape of a plate, and its extension width refers to the dimension in the width direction of the battery cell 22, and the extension width of the second cavity wall 212 is also the width of the battery cell 22. The extension width of the second buffer layer 232 is the same as the extension width of the second cavity wall 212, which means that both ends of the second buffer layer 232 extend toward the first cavity wall 211 and abut the first cavity wall 211, or abut the end of the first buffer layer 231. Here, the second buffer layer 232 is in abutment with the first buffer layer 231 to avoid worsening the expansion force of the battery cell 22. The flat second buffer layer 232 can be obtained only by cutting, and the processing process is simple.

[0082] The second buffer layer 232 increases the buffer area of ​​the corner surface 222 of the battery cell 22, further improves the protection, and facilitates processing.

[0083] Please refer to Fig.12 and Fig.13 In one embodiment of the present invention, the surface of the second buffer layer 232 facing the corner surface 222 is a curved surface, and the curvature of the curved surface is less than or equal to the curvature of the corner surface 222 .

[0084] In this example, the surface of the second cushion layer 232 facing the corner surface 222 is a curved surface, which may be a circular arc surface or a non-circular arc surface, which is not limited here. The radian refers to the ratio of the arc length to the radius of the circle corresponding to the arc length. The radian of the curved surface is less than or equal to the radian of the corner surface 222, so that the curvature of the curved surface is less than or equal to the curvature of the corner surface 222, so that the corner surface 222 will not be squeezed too much on the basis of reducing the distance between the curved surface and the corner surface 222.

[0085] The second buffer layer 232 of this structure can increase the restraint on the expansion of the corner surface 222 and reduce the risk of the top shell of the corner surface 222 breaking.

[0086] Please refer to Fig.13 In one embodiment of the present invention, the surface of the second buffer layer 232 away from the corner surface 222 is a curved surface, and the second buffer layer 232 is in the shape of a curved plate with uniform thickness.

[0087] In this example, the surface of the second buffer layer 232 away from the corner surface 222, that is, the surface facing the second cavity wall surface 212, is also a curved surface, and the curvature of the two curved surfaces of the second buffer layer 232 is the same, so that the second buffer layer 232 is a curved plate with uniform thickness. The curved plate can be formed by bending a plane structure to a certain curvature.

[0088] The second buffer layer 232 of this structure is easy to process, has a small overall volume, occupies little space, and reduces the impact on the margin of the battery cell 20 group.

[0089] Please refer to Fig.12 In one embodiment of the present invention, the surface of the second buffer layer 232 away from the corner surface 222 is a plane.

[0090] In this example, the surface of the second cushion layer 232 facing the second cavity wall 212 is a plane, which can fit with the second cavity wall 212, and the arc surface of the other surface is adapted to the corner surface 222, thereby improving the cushioning effect. The second cushion layer 232 of this structure is easy to install.

[0091] Please refer to Figure 5 and Figure 6 In one embodiment of the present invention, the thickness of the first buffer layer 231 gradually increases in a direction from the middle of the large surface 221 to any of the corner surfaces 222 .

[0092] In this embodiment, the thickness variation of the first buffer layer 231 is set to gradually increase, that is, the surface of the first buffer layer 231 facing the battery cell 22 can be an inclined surface or a curved surface, which is not limited here.

[0093] The surface of the first buffer layer 231 of the structure is relatively smooth, which can reduce sharp parts and avoid the risk of cracking caused by stress concentration.

[0094] Please refer to Figure 3 In one embodiment of the present invention, the minimum thickness of the first buffer layer 231 is d1, and the maximum thickness of the first buffer layer 231 is d2, wherein the range of d1 / d2 is greater than or equal to 10% and less than or equal to 50%.

[0095] In this embodiment, the ratio d1 / d2 of the minimum thickness to the maximum thickness of the first buffer layer 231 is set within a range of greater than or equal to 10% and less than or equal to 50%. For example, the ratio can be 15%, 20%, 25%, 30%, 35%, 40%, etc., which can enhance the restraint force on the lateral movement of the pole piece after expansion, and make the first buffer layer 231 corresponding to the middle part of the large surface 221 have a better buffering effect. Optionally, when the minimum thickness of the first buffer layer 231 is 10% of the maximum thickness value, the thickness of the transition part from the middle to the edge of the first buffer layer 231 can be 15%, 20%, 25%, 30%, 35%, 40%, respectively, thereby forming a gradually increasing trend.

[0096] The first buffer layer 231 within this ratio range can achieve a better anti-cracking effect and reduce the impact on the group margin.

[0097] In an embodiment of the present invention, the cushion layer is made of rubber or sponge.

[0098] In this example, the buffer layer is made of an elastic material, such as rubber or sponge. This material has good compressibility and low cost, which improves the buffering effect of the buffer layer.

[0099] In one embodiment of the present invention, the compression rate of the buffer layer is greater than or equal to 75%.

[0100] In this example, the compression rate value of the buffer layer refers to the ratio of the difference between the thickness value of the buffer layer before compression and the thickness value after compression to the thickness of the buffer layer before compression. The compression rate value is set within a range greater than or equal to 75%, for example, 80%, 85%, 90%. Optionally, the compression rate value is 80%, which has good compression performance, is convenient for material selection, and reduces costs. The buffer layer can have a large compression space, providing a large expansion space for the battery cell 22, reducing cracking while avoiding deterioration of expansion force.

[0101] Please refer to Figure 3 In one embodiment of the present invention, the thickness of the buffer layer is d3, and the thickness of the battery cell 22 is d4, wherein the range of d3 / d4 is greater than or equal to 2% and less than or equal to 15%.

[0102] In this embodiment, when the buffer layer is a structure with uniform thickness, the thickness d3 of the buffer layer is the thickness at each position. When the thickness of the buffer layer is non-uniform, the thickness d3 of the buffer layer is the maximum thickness value of the buffer layer. The thickness d4 of the battery cell 22 refers to the size of the battery cell 22 in the width direction of the shell 21. The range of d3 / d4 is greater than or equal to 2%, and less than or equal to 15%, for example, 3%, 5%, 8%, 9%, 12% or 13%, etc. In an optional example, d3 / d4 is set to 10%, which has a better buffering effect and lower elongation consumption, and occupies less space in the shell 21.

[0103] The buffer layer of this structure has a certain buffering effect and a small thickness, and has little effect on the group margin of the battery cell 20 .

[0104] The present invention further provides a battery device 100, which includes any of the above-mentioned battery cells 20. The battery cell 20 of the battery device 100 adopts all the technical solutions of all the above-mentioned embodiments, and thus has at least all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be described one by one here.

[0105] The battery device 100 may be a battery module or a battery pack.

[0106] The present invention further provides an electric device, comprising any of the above-mentioned battery devices 100. The battery device 100 of the electric device adopts all the technical solutions of all the above-mentioned embodiments, and thus has at least all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be described one by one here.

[0107] The power-consuming device may be a mobile phone, a laptop computer, a battery car, an electric car, an energy storage station, etc. The present application does not limit the specific type of the power-consuming device. When the power-consuming device includes the battery device 100, the battery device 100 may provide power.

[0108] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the inventive concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A battery cell, characterized in that: The battery cell comprises: a housing forming a mounting cavity; and at least one battery cell, the battery cell being disposed in the mounting cavity; The peripheral side of the battery core includes two oppositely disposed large surfaces and two oppositely disposed corner surfaces, and a transition zone between the large surfaces and the corner surfaces, and the shell includes two oppositely disposed first cavity wall surfaces and two oppositely disposed second cavity wall surfaces; A buffer layer is provided between at least one of the large surfaces and the first cavity wall surface, and the buffer layer is set as a first buffer layer. In the direction from the middle of the large surface to any of the corner surfaces, the thickness of the first buffer layer increases gradually; And / or, a buffer layer is provided at least partially between two adjacent battery cells, and the buffer layer between two adjacent battery cells is a third buffer layer, and the thickness of the third buffer layer increases in the direction from the middle of the large surface to any corner surface.

2. The battery cell according to claim 1, characterized in that: At least the transition zone is provided with the buffer layer.

3. The battery cell according to claim 2, characterized in that: The surface of the buffer layer facing the transition zone is a plane or a curved surface.

4. The battery cell according to claim 1, characterized in that: The extension length of the first buffer layer is the same as the extension length of the first cavity wall.

5. The battery cell according to claim 1, characterized in that: A buffer layer is provided between at least one of the corner surfaces and the second cavity wall surface, and the buffer layer is configured as a second buffer layer.

6. The battery cell according to claim 5, characterized in that: The second buffer layer is in the shape of a flat plate, and an extension width of the second buffer layer is the same as an extension width of the second cavity wall.

7. The battery cell according to claim 5, characterized in that: The surface of the second buffer layer facing the corner surface is a curved surface, and the curvature of the curved surface is less than or equal to the curvature of the corner surface.

8. The battery cell according to claim 7, characterized in that: The surface of the second buffer layer away from the corner surface is a curved surface, and the second buffer layer is in the shape of a curved plate with uniform thickness.

9. The battery cell according to claim 7, characterized in that: A surface of the second buffer layer facing away from the corner surface is a plane.

10. The battery cell according to claim 1, characterized in that: In a direction from the middle of the large surface to any one of the corner surfaces, the thickness of the first buffer layer gradually increases.

11. The battery cell according to claim 10, characterized in that: The minimum thickness of the first buffer layer is d1, and the maximum thickness of the first buffer layer is d2, wherein the range of d1 / d2 is greater than or equal to 10% and less than or equal to 50%.

12. The battery cell according to any one of claims 1 to 11, characterized in that: The material of the buffer layer is rubber or sponge.

13. The battery cell according to claim 12, characterized in that: The compression rate of the buffer layer is in the range of greater than or equal to 75%.

14. The battery cell according to any one of claims 1 to 11, characterized in that: The thickness of the buffer layer is d3, and the thickness of the battery cell is d4, wherein the range of d3 / d4 is greater than or equal to 2% and less than or equal to 15%.

15. A battery device, characterized in that: The battery device comprises the battery cell according to any one of claims 1 to 14.

16. An electrical equipment, characterized in that: Comprising the battery device as claimed in claim 15.

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