Battery pack

Abstract

The utility model provides a battery pack, the battery pack comprises a plurality of single batteries and a buffer member, and the plurality of single batteries are arranged at intervals; the buffer part is arranged between the adjacent single batteries, the buffer part comprises a plurality of mutually connected elements, the side wall of each element is provided with N planes and N curved surfaces, the N planes and the N curved surfaces are alternately connected end to end, the elements are provided with through holes, and the curved surfaces are bent towards the through holes. The elements have zero Poisson's ratio or negative Poisson's ratio, so that the single batteries generate an extrusion effect on the buffer parts among the single batteries after deformation, the elements in the buffer parts can absorb the deformation of the single batteries, the width of the battery pack in the width direction is not increased, and the battery pack can be prevented from being damaged. Therefore, the contact area between the binding belt and the single batteries and the pressure of the single batteries on the binding belt are not reduced, and the reliability of the battery pack is favorably maintained.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of batteries, and in particular to a battery pack. BACKGROUND

[0002] After the battery pack works for a period of time, especially near the end of life of the single battery, the single battery will produce obvious expansion. This will cause the material between the single batteries to be squeezed and deformed, and the width of the material between the single batteries will exceed the width of the single battery, thereby causing the steel belt on the battery module to be stressed, and the stress deformation of the steel belt will change the contact area of the steel belt and the single battery, which will affect the tightness of the steel belt to the single battery, and further, this will affect the reliability and safety of the battery pack. SUMMARY

[0003] The embodiments of the present application provide a battery pack to solve the problem of reduced tightness of the steel belt to the single battery after the single battery is deformed.

[0004] The embodiments of the present application provide a battery pack, which includes a plurality of single batteries and a buffer, and the plurality of single batteries are arranged at intervals; the buffer is arranged between adjacent single batteries, and the buffer includes a plurality of base elements connected to each other, the side wall of the base element has N planes and N curved surfaces, the N planes and the N curved surfaces are alternately connected end to end, the base element is provided with a through hole, and the curved surface is curved towards the through hole.

[0005] Optionally, the planes of adjacent base elements abut each other, and the curved surfaces of adjacent base elements abut to form a splicing hole.

[0006] Optionally, the curved surface is a circular arc.

[0007] Optionally, N is a multiple of 2, and the base element is a central symmetric figure.

[0008] Optionally, in the thickness direction of the single battery, the height of the base element is H, and 0.5 mm≤H≤20 mm.

[0009] Optionally, the diameter of the through hole is R, and R≤0.25H.

[0010] Optionally, part of the curved surface at opposite ends of the buffer faces the single battery.

[0011] Optionally, the battery pack further includes a stress sensor, and the stress sensor is arranged in the buffer.

[0012] Optionally, the stress sensor is arranged in the through hole; or the curved surfaces of adjacent base elements abut to form a splicing hole, and the stress sensor is arranged in the splicing hole.

[0013] Optionally, the stress sensor has a plurality of stress sensors, each two of the plurality of stress sensors form a group, and each group of stress sensors is symmetrically arranged along a direction perpendicular to the thickness direction of the single battery.

[0014] Advantages of the present application:

[0015] The side wall of the unit has N planes and N curved surfaces, the N planes and the N curved surfaces are alternately connected in a closed loop, and the curved surfaces are curved towards the through hole. The part of the unit located at the curved surface forms a concave structure, and the part of the unit located at the plane forms a flat structure. During use, the plane can abut against the single battery, and the single battery can exert a force on the plane during deformation. The plane can ensure that the contact area with the single battery is large enough, thereby reducing the local pressure on the unit. The plane can further transmit the pressure to the curved surface, and the curved surface can be gradually folded under pressure, so that the space formed by the concave curved surface is occupied. Thus, the deformation space of the buffer member is transferred to the space occupied by the curved surface of the unit, so as to realize zero or negative Poisson's ratio of the unit, thereby keeping the width of the buffer member from exceeding the width of the single battery, reducing the extrusion of the buffer member, ensuring the tightness of the steel belt on the single battery, and further ensuring the reliability and safety of the steel belt on the battery pack.

[0016] The unit is provided with a through hole, and part of the material of the unit will move to the through hole until the through hole is filled after the unit is deformed under stress, thereby occupying the space of the through hole to realize zero or negative Poisson's ratio of the unit. Thus, the deformation space of the buffer member is transferred to the space occupied by the through hole of the unit, thereby keeping the width of the buffer member from exceeding the width of the single battery, reducing the extrusion of the buffer member, ensuring the tightness of the steel belt on the single battery, and further ensuring the reliability and safety of the steel belt on the battery pack. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiment description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0018] Figure 1 The structural schematic diagram of the battery pack provided by the embodiments of the present application is shown in the following figure:

[0019] Figure 2 The structural schematic diagram of the unit provided by the embodiments of the present application is shown in the following figure:

[0020] Figure 3 The structural schematic diagram of an embodiment of the buffer member provided by the embodiments of the present application is shown in the following figure:

[0021] Figure 4 Structure diagram of another embodiment of the buffer provided by the embodiment of the present application;

[0022] Figure 5 Structure diagram of another embodiment of the buffer provided by the embodiment of the present application.

[0023] Legend of reference signs:

[0024] Monomer battery 200, buffer 100, cell 10, plane 12, curved surface 14, through hole 16

[0025] Splicing hole 18, stress sensor 300. DETAILED DESCRIPTION

[0026] In order for those skilled in the art to better understand the technical solutions of the present application, the present application will be described in detail below in combination with the drawings. The description in this part is only exemplary and explanatory, and should not have any limiting effect on the protection scope of the present application.

[0027] It should be noted that: similar reference signs and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0028] It should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the present application is usually placed, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second", "third" and the like are only used for differentiation and cannot be understood as indicating or implying relative importance.

[0029] In addition, the terms "horizontal", "vertical", "overhanging" and the like do not mean that the components must be absolutely horizontal or overhanging, but can be slightly inclined. For example, "horizontal" only means that its direction is more horizontal relative to "vertical", and does not mean that the structure must be completely horizontal, but can be slightly inclined.

[0030] Reference Figures 1 to 3 , Figure 1 Structure diagram of the battery pack provided by the embodiment of the present application, Figure 2 Structure diagram of the cell 10 provided by the embodiment of the present application, Figure 3 Structure diagram of an embodiment of the buffer 100 provided by the embodiment of the present application.

[0031] The application provides a battery pack, which comprises a plurality of single batteries 200 and a buffer 100, the plurality of single batteries 200 are arranged at intervals, the buffer 100 is arranged between adjacent single batteries 200, and the buffer 100 comprises a plurality of base units 10. The plurality of base units 10 can be arranged in the thickness direction of the single battery 200, that is, the plurality of base units 10 can be arranged on the largest side of the single battery 200, the single battery 200 is most likely to deform in this direction, and the deformation amount is also the largest, so the buffer effect is good. The plurality of base units 10 can also be arranged in the width direction of the single battery 200, that is, the plurality of base units 10 can be arranged on the smallest side of the single battery 200.

[0032] The side wall of the base unit 10 has N planes 12 and N curved surfaces 14, the N planes 12 and the N curved surfaces 14 are alternately connected in a closed loop, and the curved surface 14 is curved towards the through hole 16. The part of the base unit 10 located at the curved surface 14 forms a concave structure, and the part of the base unit 10 located at the plane 12 forms a flat structure.

[0033] In use, the plane 12 can abut against the single battery 200, and the single battery 200 will exert a force on the plane 12 during deformation. The plane 12 can ensure that the contact area with the single battery 200 is large enough, thereby reducing the local pressure on the base unit 10. The plane 12 will continue to transmit the pressure to the curved surface 14, the curved surface 14 will gradually fold under pressure, so that the space formed by the concave curved surface 14 is occupied. Thus, the deformation space of the buffer 100 is transferred to the space occupied by the curved surface 14 of the base unit 10, so as to realize the zero or negative Poisson's ratio of the base unit 10, thereby keeping the width of the buffer 100 from exceeding the width of the single battery 200, reducing the extrusion of the buffer 100, ensuring that the tightness of the steel belt to the single battery 200 is not affected, and further ensuring the reliability and safety of the battery pack.

[0034] The base unit 10 is provided with a through hole 16, which can be located at the middle position or the approximate middle position of the base unit 10, so that the force on the base unit 10 near the through hole 16 is more balanced, and the deformation is more balanced. The through hole 16 can also be located at the eccentric position of the base unit 10. After the base unit 10 is deformed under force, part of the material of the base unit 10 will move to the through hole 16 until the through hole 16 is filled, thereby occupying the space of the through hole 16, so as to realize the zero or negative Poisson's ratio of the base unit 10. Thus, the deformation space of the buffer 100 is transferred to the space occupied by the through hole 16 of the base unit 10, thereby keeping the width of the buffer 100 from exceeding the width of the single battery 200, reducing the extrusion of the buffer 100, ensuring that the tightness of the steel belt to the single battery 200 is not affected, and further ensuring the reliability and safety of the battery pack.

[0035] In an embodiment, N is a multiple of 2, N can be 2, 4, 6, 8, 10, etc., and the basic unit 10 is a central symmetric figure. The advantage of this setting is that when the basic unit 10 is arranged between the single batteries 200, the basic unit 10 can be symmetrically stressed, thereby evenly distributing the pressure on the basic unit 10, preventing the basic unit 10 from being irreversibly deformed after local pressure exceeds the limit. For example, when N is equal to 2, the outer contour of the basic unit 10 forms a quasi-regular quadrilateral; when N is equal to 4, the outer contour of the basic unit 10 forms a quasi-regular octagon; and when N is equal to 6, the outer contour of the basic unit 10 forms a quasi-regular dodecagon.

[0036] The length of the plane 12 and the straight line length of the curved surface 14 can be equal, so that the closed loop formed by the N planes 12 and the N curved surfaces 14 connected alternately is a quasi-regular polygon.

[0037] Alternatively, the curved surface 14 can be in the shape of a circular arc, and the curvature of the curved surface 14 can be 1 / 4 of a circle, 1 / 2 of a circle, 1 / 4 of a circle, 1 / 2 of a circle, etc. The curved surface 14 in the shape of a circular arc is smooth in transition, and the resisting force on the basic unit 10 at the curved surface 14 is the smallest during the deformation of the basic unit 10, thereby being more conducive to deformation. In addition, the curved surface 14 in the shape of an arc has a restoring elastic force, and after the external force is removed, the curved surface 14 can restore to the original state by relying on its own elasticity, thereby being reusable and improving the utilization efficiency of the basic unit 10.

[0038] In an embodiment, in the thickness direction of the single battery 200, the height of the basic unit 10 is H, the height direction of the basic unit 10 is the thickness direction of the single battery 200, and 0.5 mm≤H≤20 mm. H can be 0.5 mm, 2 mm, 4 mm, 5 mm, 8 mm, 10 mm, 12 mm, 16 mm, 18 mm, 20 mm, etc. Within this range, the basic unit 10 can play a buffering role without occupying too much installation space of the single battery 200. When the basic unit 10 is greater than this value, the buffering effect of the basic unit 10 cannot be greatly improved, but the installation space of the single battery 200 will be excessively occupied. When the basic unit 10 is less than this value, the buffering effect of the basic unit 10 will be greatly weakened and cannot play a role in buffering and reducing the extrusion of the single battery 200 on the bandage.

[0039] Alternatively, the diameter of the through hole 16 is R, and R≤0.25H. R can be 0.25H, 0.2H, 0.15H, 0.1H, etc. As the size of the basic unit 10 increases, the diameter of the through hole 16 also increases accordingly. Within the above range, the through hole 16 will not damage the overall structural strength of the basic unit 10, so that when the basic unit 10 is subjected to external force, the basic unit 10 can slowly deform until the limit state, and after the external force disappears, the basic unit 10 can still restore to the original state.

[0040] Optionally, the planes 12 of the adjacent units 10 abut against each other, and the curved surfaces 14 of the adjacent units 10 abut to form the splicing holes 18. The plane 12 is flat, and when force is applied, the force can be smoothly transmitted to the abutting plane. In addition, the abutting of the planes 12 can ensure the stability of the arrangement of the units 10, and prevent the units 10 from loosening during force application.

[0041] Optionally, the arrangement shown in the embodiment is as follows: Figure 3 The units 10 are connected to each other by the planes 12, and the planes 12 at opposite ends of the buffer 100 are used to abut against the single batteries 200, and the curved surfaces 14 face the single batteries 200. In this embodiment, the buffer 100 has at least two parts, which are referred to as a first part and a second part. The second part is provided with the first part on opposite sides thereof. The first part and the second part form a sandwich structure. The first part is used to abut against the single batteries 200, and the units 10 in the first part are arranged at intervals. The planes 12 of the units 10 in the first part are used to abut against the single batteries 200. The planes 12 of the units 10 in the second part abut against each other to form a whole. At the same time, the planes 12 of the units 10 in the second part are also connected to the planes 12 of the units 10 in the first part, so that the first part and the second part are connected to form a whole.

[0042] In this embodiment, the buffer 100 is divided into multiple parts, and the multiple parts are connected to each other by the respective planes 12 to form a whole. When the buffer 100 is subjected to force, the units 10 transmit the force to each other by the planes 12. The planes 12 can increase the contact area relative to the curved surfaces 14, thereby improving the stability of the whole structure, so that the buffer 100 will not loosen during use.

[0043] Reference is made to Figure 1 , Figure 4 and Figure 5 , Figure 4 FIG. 4 is a structural schematic view of another embodiment of the buffer 100 provided in the embodiment, Figure 5 FIG. 5 is a structural schematic view of another embodiment of the buffer 100 provided in the embodiment.

[0044] In an embodiment, the battery pack further includes a stress sensor 300 arranged in the buffer 100. The stress sensor 300 can be a piezoelectric sensor, an electrostatic sensor, or a capacitive sensor. The units 10 act on the stress sensor 300 synchronously during deformation. Even if the stress sensor 300 does not deform, it can still sense stress, so as to collect a mechanical signal. The manager in the battery pack can obtain the mechanical signal, so that the management decision of the manager is more accurate.

[0045] In addition, the stress sensor 300 is arranged in the buffer 100, and the unit cell 10 wraps the stress sensor 300, so that the stress sensor 300 does not directly contact the single battery 200 to obtain pressure data, thereby avoiding the stress sensor 300 from damaging the single battery 200. In the related art, the stress sensor 300 is attached between large faces of the single battery 200, which changes the original mechanical boundary of the battery module, and under long-term pressure, the stress sensor 300 may pierce the blue film coated on the single battery 200, affecting electrical safety.

[0046] Further, the stress sensor 300 can be arranged in the through hole 16, and the through hole 16 itself is a closed environment, thereby protecting the stress sensor 300. Of course, the adjacent unit cell 10 surrounds to form the splicing hole 18, and the stress sensor 300 can also be arranged in the splicing hole 18, and the splicing hole 18 can also protect the stress sensor 300.

[0047] Optionally, the stress sensor 300 has a plurality of stress sensors 300, and each two of the plurality of stress sensors 300 form a group, and each group of stress sensors 300 is arranged symmetrically along a direction perpendicular to the thickness direction of the single battery 200. Each stress sensor 300 can obtain a mechanical signal, and each two stress sensors 300 form a group, thereby doubling the signal strength at a certain position to achieve the purpose of locally strengthening the signal.

[0048] In the description of the present application, it should be explained that, unless otherwise explicitly specified and limited, the terms "arrange", "mount", "connect", "connect" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, or it can be connected inside two elements. For ordinary skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0049] It should be noted that, in this paper, the relationship terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between the entities or operations. Moreover, the terms "include", "contain" or any other variant thereof are intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or includes elements inherent in such process, method, article or equipment. Without more limitation, the element defined by the sentence "including a" does not exclude the existence of other same elements in the process, method, article or equipment including the element.

[0050] While the embodiments of the present application have been illustrated and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made therein without departing from the spirit and scope of the present application, which should be limited only by the appended claims and their equivalents.

Claims

1. A battery pack, characterized in that, include: Multiple individual battery cells are arranged at intervals between them; A buffer element is disposed between adjacent individual cells. The buffer element includes multiple interconnected basic units. The sidewalls of the basic units have N planes and N curved surfaces, which are alternately connected end to end. The basic units have through holes, and the curved surfaces are bent toward the through holes.

2. The battery pack according to claim 1, characterized in that, The planes of adjacent basic elements abut against each other, and the curved surfaces of adjacent basic elements abut against each other to form a splicing hole.

3. The battery pack according to claim 1, characterized in that, The surface is an arc shape.

4. The battery pack according to claim 1, characterized in that, N is a multiple of 2, and the primitive is a centrally symmetric figure.

5. The battery pack according to any one of claims 1 to 4, characterized in that, In the thickness direction of the single cell, the height of the cell is H, where 0.5 mm ≤ H ≤ 20 mm.

6. The battery pack according to claim 5, characterized in that, The diameter of the through hole is R, where R ≤ 0.25H.

7. The battery pack according to claim 4, characterized in that, The curved surfaces located at opposite ends of the buffer member face the individual battery cell.

8. The battery pack according to claim 1, characterized in that, The battery pack also includes a stress sensor disposed in the buffer.

9. The battery pack according to claim 8, characterized in that, The stress sensor is disposed in the through hole; or, the curved surfaces of adjacent elements are abutted to form a splicing hole, and the stress sensor is disposed in the splicing hole.

10. The battery pack according to claim 8, characterized in that, The stress sensor is a plurality of them, and each pair of stress sensors is arranged in a group. Each group of stress sensors is symmetrically arranged along the thickness direction perpendicular to the individual battery cell.

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