Buffer piece, battery cell monomer, battery pack and electric equipment

Abstract

The utility model discloses a buffer piece, a battery cell monomer, a battery pack and electric equipment. The buffer piece comprises a buffer body part and a thickening part, the buffer part is used for the single battery cell, the single battery cell comprises a shell and a pole core, the pole core is arranged in the shell and provided with a thinned part and a pole core body part, at least one of the two ends of the pole core body part in the first direction is provided with the thinned part, and the buffer body part is suitable for being located between the pole core body part and the inner wall of the shell. At least one of the two ends of the buffer body part in the first direction is connected with a thickening part, the thickening part is suitable for being located between the thinned part and the shell, and the thickness of the thickening part is larger than or equal to that of the buffer body part. According to the buffer piece disclosed by the utility model, the buffer piece can improve the uniformity and transmission effect of the lithium ions in the battery cell monomers, and reduce safety risks such as lithium separation, so that the charge-discharge performance and safety of the battery cell monomers can be improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to battery technology field especially is related to a buffer, electric core single body, battery pack and electric equipment. BACKGROUND

[0002] The safety design of battery is paid more and more attention. The electrode sheet in the electric core single body is generally formed by coating the slurry on the current collector, so that the electrode sheet forms the main body area, the thinning area and the empty foil area, the empty foil area is used to connect with the pole, and the thickness of the thinning area is less than the main body area. When a plurality of electrode sheets are laminated or wound to form a pole core, the electrode sheet gap at the edge of the pole core end is large, which is not conducive to the transmission of lithium ions at this place, so that the uniformity of lithium ions in and out of the plurality of electrode sheets is not high, and it is easy to induce the lithium precipitation and other safety problems of the electric core single body. SUMMARY

[0003] The utility model aims at at least one of the technical problems existing in the prior art. Therefore, the utility model provides a buffer, which can improve the uniformity of lithium ion extraction and embedding in the electric core single body, reduce the lithium precipitation and other safety risks, and improve the charge and discharge performance and safety of the electric core single body.

[0004] The utility model also provides an electric core single body, which comprises the above buffer.

[0005] The utility model also provides a battery pack, which comprises the above electric core single body.

[0006] The utility model also provides an electric equipment, which comprises the above battery pack.

[0007] The buffer according to the utility model embodiment comprises a buffer body part and a thickening part. The buffer is used for an electric core single body, the electric core single body comprises a shell and a pole core, the pole core is arranged in the shell, the pole core has a thinning part and a pole core body part, at least one end of the pole core body part in the two ends along a first direction has the thinning part, the buffer is arranged in the shell, the buffer body part is suitable for being located between the pole core body part and the inner wall of the shell. At least one end of the two ends of the buffer body part along the first direction is connected with the thickening part, the thickening part is suitable for being located between the thinning part and the shell, and the thickness of the thickening part is greater than or equal to the thickness of the buffer body part.

[0008] According to the buffer piece, the buffer piece is arranged between the pole core and the shell, at least one end of the buffer body part in the first direction is connected with the thickened part with greater thickness, the thickened part is suitable to be located between the thinned part and the shell, the gap between the thinned part and the shell can be effectively supplemented, the plurality of pole pieces in the pole core can be better attached at the thinned part, the uniformity and transmission effect of lithium ion discharging and embedding between the plurality of pole pieces can be improved, the possibility of lithium dendrite growth of the thinned part can be reduced, and the safety problems such as lithium precipitation of the pole core can be avoided, so that the charge-discharge performance and safety of the battery cell can be effectively improved. It is also beneficial to reduce the swelling force in the later life stage, thereby reducing the internal resistance growth of the battery cell caused by the side reaction in the later life stage.

[0009] According to some embodiments of the utility model, in the direction from the buffer body part to the thickened part, the thickness of the thickened part gradually increases

[0010] According to some embodiments of the utility model, in the first direction, the thickness of the buffer body part is constant, and the thickness of one end of the thickened part close to the buffer body part is equal to the thickness of the buffer body part.

[0011] According to some embodiments of the utility model, in the direction from the buffer body part to the thickened part, at least one side of the thickened part in the thickness direction is inclined to form a thickened surface in a direction away from the other side of the thickness direction.

[0012] In some embodiments of the utility model, the thickened surface is a plane, an arc surface or a stepped surface.

[0013] According to some embodiments of the utility model, the buffer body part is provided with a through hole, and the through hole penetrates the buffer body part in the thickness direction of the buffer body part.

[0014] In some embodiments of the utility model, the through hole is one,

[0015] The distance between the inner side wall of the through hole and the outer side wall of the buffer body part is a, and a satisfies: 3mm≤a≤10mm;

[0016] Or, one side of the through hole facing the thickened part is open, and the thickened part is used for plugging the open port of the through hole.

[0017] In some embodiments of the utility model, the through hole is a plurality of through holes arranged at intervals.

[0018] According to some embodiments of the utility model, the insulation resistance of the buffer piece is greater than or equal to 500MΩ;

[0019] And / or, the thermal conductivity of the buffer piece is less than or equal to 0.03W / (m·℃).

[0020] According to some embodiments of the present application, at least one side of the thickness direction of the buffer member is provided with a coating layer for bonding with the shell or the pole core.

[0021] According to some embodiments of the present application, the buffer member is a polyethylene member, a polypropylene member, a polystyrene member, an ethylene-vinyl acetate copolymer resin member, an ethylene-propylene-diene rubber member, a silicone rubber member or an aerogel member.

[0022] According to some embodiments of the present application, the buffer member is located at least one side of the pole core along the second direction, and the second direction is perpendicular to the first direction.

[0023] In some embodiments of the present application, the buffer member is arranged at least one side of the pole core along the third direction, and the first direction, the second direction and the third direction are perpendicular to each other.

[0024] In some embodiments of the present application, the first direction is the height direction of the battery cell, the second direction is the width direction of the battery cell, and the third direction is the length direction of the battery cell.

[0025] In some embodiments of the present application, the first direction is the length direction of the battery cell, the second direction is the height direction of the battery cell, and the third direction is the width direction of the battery cell.

[0026] According to the battery cell of the present application, the buffer member is arranged in the shell and includes a buffer body part and a thickened part, the buffer body part is suitable to be located between the pole body part and the inner wall of the shell, at least one end of the buffer body part along the first direction is connected with the thickened part, the thickened part is suitable to be located between the thinned part and the shell, the thickness of the thickened part is greater than or equal to the thickness of the buffer body part, and the thickness of the thickened part gradually increases in the direction from the buffer body part to the thickened part.

[0027] According to the electric core monomer provided in the embodiment of the present application, the buffer member is arranged between the pole core and the shell, and at least one end of the buffer body part in the first direction is connected with the thickened part with a larger thickness, the thickened part is suitable to be located between the thinned part and the shell, the gap between the thinned part and the shell can be effectively filled, the multiple pole pieces in the pole core can be better attached at the thinned part, the uniformity and transmission effect of lithium ions in the multiple pole pieces can be improved, the possibility of lithium dendrite growth in the thinned part can be reduced, and the safety problems such as lithium precipitation in the pole core can be avoided, so that the charge-discharge performance and safety of the electric core monomer can be effectively improved.

[0028] According to the battery pack provided in the embodiment of the present application, the buffer member is arranged between the pole core and the shell, and at least one end of the buffer body part in the first direction is connected with the thickened part with a larger thickness, the thickened part is suitable to be located between the thinned part and the shell, the gap between the thinned part and the shell can be effectively filled, the multiple pole pieces in the pole core can be better attached at the thinned part, the uniformity and transmission effect of lithium ions in the multiple pole pieces can be improved, the possibility of lithium dendrite growth in the thinned part can be reduced, and the safety problems such as lithium precipitation in the pole core can be avoided, so that the charge-discharge performance and safety of the electric core monomer can be effectively improved.

[0029] According to the battery pack provided in the embodiment of the present application, the buffer member is arranged between the pole core and the shell, and at least one end of the buffer body part in the first direction is connected with the thickened part with a larger thickness, the thickened part is suitable to be located between the thinned part and the shell, the gap between the thinned part and the shell can be effectively filled, the multiple pole pieces in the pole core can be better attached at the thinned part, the uniformity and transmission effect of lithium ions in the multiple pole pieces can be improved, the possibility of lithium dendrite growth in the thinned part can be reduced, and the safety problems such as lithium precipitation in the pole core can be avoided, so that the charge-discharge performance and safety of the electric core monomer can be effectively improved.

[0030] According to the electric device provided in the embodiment of the present application, the buffer member is arranged between the pole core and the shell, and at least one end of the buffer body part in the first direction is connected with the thickened part with a larger thickness, the thickened part is suitable to be located between the thinned part and the shell, the gap between the thinned part and the shell can be effectively filled, the multiple pole pieces in the pole core can be better attached at the thinned part, the uniformity and transmission effect of lithium ions in the multiple pole pieces can be improved, the possibility of lithium dendrite growth in the thinned part can be reduced, and the safety problems such as lithium precipitation in the pole core can be avoided, so that the charge-discharge performance and safety of the electric core monomer can be effectively improved.

[0031] According to the electric device provided in the embodiment of the present application, the buffer member is arranged between the pole core and the shell, and at least one end of the buffer body part in the first direction is connected with the thickened part with a larger thickness, the thickened part is suitable to be located between the thinned part and the shell, the gap between the thinned part and the shell can be effectively filled, the multiple pole pieces in the pole core can be better attached at the thinned part, the uniformity and transmission effect of lithium ions in the multiple pole pieces can be improved, the possibility of lithium dendrite growth in the thinned part can be reduced, and the safety problems such as lithium precipitation in the pole core can be avoided, so that the charge-discharge performance and safety of the electric core monomer can be effectively improved.

[0032] Additional aspects and advantages of the present application will be set forth in part in the following description, and in part will become apparent to those skilled in the art upon examination of the following or can be learned by practice of the application. BRIEF DESCRIPTION OF DRAWINGS

[0033] The above and / or additional aspects and advantages of the present application will become apparent and be readily appreciated from the following description, taken in conjunction with the accompanying drawings, in which:

[0034] Figure 1 is a cross-sectional view of a buffer according to an embodiment of the present application, wherein the thickened portion is connected to one end of the buffer body portion in the first direction;

[0035] Figure 2 is a cross-sectional view of a battery cell according to an embodiment of the present application, wherein the thickened portion is connected to one end of the buffer body portion in the first direction;

[0036] Figure 3 is a cross-sectional view of a buffer according to an embodiment of the present application, wherein the thickened portions are connected to both ends of the buffer body portion in the first direction;

[0037] Figure 4 is a cross-sectional view of a battery cell according to an embodiment of the present application, wherein the thickened portions are connected to both ends of the buffer body portion in the first direction;

[0038] Figure 5 is a side view of a buffer according to an embodiment of the present application, wherein the buffer body portion is provided with one through hole;

[0039] Figure 6 is a cross-sectional view of a buffer according to an embodiment of the present application, wherein the buffer body portion is provided with one through hole;

[0040] Figure 7 is a cross-sectional view of a battery cell according to an embodiment of the present application, wherein the buffer body portion is provided with one through hole;

[0041] Figure 8 is a side view of a buffer according to an embodiment of the present application, wherein the buffer body portion is provided with a plurality of through holes;

[0042] Figure 9 is a cross-sectional view of a buffer according to an embodiment of the present application, wherein the buffer body portion is provided with a plurality of through holes.

[0043] REFERENCE NUMERALS:

[0044] 100, buffer;

[0045] 1, buffer body portion; 11, through hole;

[0046] 2, thickened portion; 21, thickened surface;

[0047] 200, cell monomer;

[0048] 3, housing;

[0049] 4, pole core; 41, thinning portion; 42, pole core body portion; 43, positive electrode tab portion; 44, negative electrode tab portion;

[0050] 5, pole. DETAILED DESCRIPTION

[0051] The embodiments of the present application will be described in detail below, examples of which are shown in the drawings, wherein the same or similar notations represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by reference to the drawings are exemplary only, and are used only for the purpose of explaining the present application, and should not be understood as a limitation of the present application.

[0052] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like is based on the orientation or positional relationship shown in the drawings, and is only for the purpose of facilitating the description of the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the device or element referred to 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 features defined as "first" and "second" can explicitly or implicitly include one or more of the features. In the description of the present application, unless otherwise specified, the meaning of "a plurality of" is two or more.

[0053] In the description of the present application, it should be noted that, unless otherwise specified and limited, the terms "mounting", "connection", "connection" 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; it can be the communication between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0054] Reference will now be made to Figures 1-9 The buffer 100 according to the embodiment of the present application is described.

[0055] As Figures 1-4 shown, the buffer 100 according to the embodiment of the present application includes a buffer body portion 1 and a thickening portion 2.

[0056] Specifically, asFigures 1-4 As shown, the buffer 100 is used for the battery monomer 200, the battery monomer 200 includes a shell 3 and a pole core 4, the pole core 4 is arranged in the shell 3, the pole core 4 has a thinning portion 41 and a pole core body portion 42, and the pole core body portion 42 has the thinning portion 41 at least at one end of the two ends in the first direction.

[0057] It can be understood that the pole core 4 is composed of a plurality of positive electrode sheets, a plurality of negative electrode sheets and a plurality of separators, the plurality of positive electrode sheets, the plurality of negative electrode sheets and the plurality of separators correspond to each other respectively, the plurality of separators are arranged between the plurality of positive electrode sheets and the plurality of negative electrode sheets, and the plurality of positive electrode sheets, the plurality of negative electrode sheets and the plurality of separators are arranged in a stacked manner or a wound manner, and the plurality of positive electrode sheets and the plurality of negative electrode sheets are generally made by coating the prepared slurry on the surface of the current collector such as aluminum foil or copper foil. In the first direction, the thickness of the slurry at the edge position of the plurality of positive electrode sheets and the plurality of negative electrode sheets close to the end portion becomes smaller, so that the plurality of positive electrode sheets and the plurality of negative electrode sheets form the thinning portion 41 of the pole core 4 after being stacked or wound, and the cross-sectional area of the thinning portion 41 perpendicular to the first direction is smaller than the cross-sectional area of the pole core body portion 42 perpendicular to the first direction.

[0058] In the prior art, a buffer pad in the shape of a meander or other shapes is pasted outside the shell of the battery monomer, the buffer pad is opposite to the thinning portion, so that the thinning portion of the battery can be subjected to pressure when the battery monomer is assembled into a battery pack, thereby reducing the gap between the thinning portion and the shell. However, the above method has poor improvement effect and cannot well reduce the gap of the plurality of positive electrode sheets and the plurality of negative electrode sheets at the thinning portion, which is not conducive to the transmission of lithium ions at the thinning portion, and the buffer pad also occupies the space of the battery pack, thereby reducing the volumetric energy density of the battery pack.

[0059] In the present application, the buffer 100 is arranged in the shell 3, the buffer body portion 1 is suitable to be located between the pole core body portion 42 and the inner wall of the shell 3, at least one end of the buffer body portion 1 in the two ends in the first direction is connected with the thickening portion 2, the thickening portion 2 is suitable to be located between the thinning portion 41 and the shell 3, and the thickness of the thickening portion 2 is greater than or equal to the thickness of the buffer body portion 1.

[0060] By arranging the thickening portion 2 with the thickness greater than or equal to the thickness of the buffer body portion 1 between the thinning portion 41 and the shell 3, the gap between the thinning portion 41 and the shell 3 can be effectively supplemented, so that the plurality of positive electrode sheets and the plurality of negative electrode sheets in the pole core 4 can be better attached at the thinning portion 41, that is, the gap of the plurality of positive electrode sheets and the plurality of negative electrode sheets at the thinning portion 41 is reduced, which is conducive to the transmission of lithium ions between the plurality of electrode sheets, so that the uniformity and transmission effect of lithium ions in and out of the plurality of electrode sheets can be improved, thereby the possibility of lithium dendrite growth of the thinning portion 41 can be reduced, and the safety problems such as lithium precipitation of the pole core 4 can be avoided, and thus the charge and discharge performance and safety of the battery monomer 200 can be effectively improved. It is also conducive to reducing the swelling force in the later life, thereby reducing the internal resistance increase of the battery monomer 200 caused by the side reaction in the later life.

[0061] In addition, the buffer 100 is arranged inside the shell 3, without occupying the space outside the battery cell 200, so as not to affect the volume energy density of the battery pack or the battery module. At the same time, the buffer 100 can also play a buffering role, absorbing the thickness change of the pole core 4 generated in the charging and discharging process, so as to avoid the uneven deformation of the pole core 4, and thus be beneficial to prolong the service life of the battery cell 200.

[0062] It should be noted that at least one of the two ends of the pole core body part 42 along the first direction has a thinning part 41, and the pole core 4 further includes a positive electrode tab part 43 and a negative electrode tab part 44, the part on the surface of the current collector such as aluminum foil or copper foil without coating slurry is formed as the positive electrode tab part 43 and the negative electrode tab part 44, the positive electrode tab part 43 and the negative electrode tab part 44 are respectively connected with the thinning part 41 and are located at one end of the thinning part 41 away from the pole core body part 42. The battery cell 200 is provided with a positive electrode column 5 and a negative electrode column 5, the positive electrode tab part 43 is connected with the positive electrode column 5, and the negative electrode tab part 44 is connected with the negative electrode column 5, so as to ensure the connection between the pole piece in the battery cell 200 and the external power supply and load, thereby realizing the charging and discharging function of the battery cell 200.

[0063] When the positive electrode column 5 and the negative electrode column 5 are arranged at the same end of the battery cell 200 along the first direction, one end of the pole core body part 42 along the first direction has a thinning part 41, and the positive electrode tab part 43 and the negative electrode tab part 44 are arranged at the same side of the thinning part 41. At this time, one end of the buffer body part 1 along the first direction is connected with the thickening part 2, and the thickening part 2 is located between the thinning part 41 and the shell 3.

[0064] When the positive electrode column 5 and the negative electrode column 5 are arranged at the two ends of the battery cell 200 along the first direction respectively, both ends of the pole core body part 42 along the first direction have a thinning part 41, and the positive electrode tab part 43 and the negative electrode tab part 44 are arranged at the two sides of the thinning part 41 respectively. At this time, both ends of the buffer body part 1 along the first direction are respectively connected with the thickening part 2, and the thickening part 2 is located between the thinning part 41 and the shell 3.

[0065] According to the buffer piece 100 of the embodiment of the utility model, the buffer piece 100 is arranged between the pole core 4 and the shell 3, and at least one end of the buffer body part 1 in the first direction is connected with the thickened part 2 with greater thickness, the thickened part 2 is suitable to be located between the thinning part 41 and the shell 3, the gap between the thinning part 41 and the shell 3 can be effectively supplemented, the plurality of pole pieces in the pole core 4 can be better fitted at the thinning part 41, the uniformity of lithium ion discharging and embedding between the plurality of pole pieces and the transmission effect can be improved, the possibility of lithium dendrite growth of the thinning part 41 can be reduced, and the safety problems such as lithium precipitation of the pole core 4 can be avoided, and then the charge-discharge performance and safety of the battery monomer 200 can be effectively improved.

[0066] In some embodiments of the utility model, as shown in Figures 1-4 The thickness of the thickened part 2 gradually increases in the direction from the buffer body part 1 to the thickened part 2. Since the thickness of the thinning part 41 gradually decreases in the direction from the pole core body part 42 to the thinning part 41, the thickness of the thickened part 2 gradually increases in the direction from the buffer body part 1 to the thickened part 2, so that the thickened part 2 can better adapt to the thinning part 41, and the gaps of the plurality of pole pieces at the thinning part 41 are uniformly distributed, so that the lithium ion can be better transmitted between the plurality of pole pieces, the safety risk such as lithium precipitation can be further reduced, and the charge-discharge performance and safety of the battery monomer 200 can be better improved. The thickened part 2 with gradually changing thickness not only makes the pole pieces at the thinning part 41 better fit, but also reduces the expansion force in the later life, thereby reducing the internal resistance growth of the battery monomer 200 caused by the side reaction in the later life.

[0067] In some embodiments of the utility model, as shown in Figures 1-4 In the first direction, the thickness of the buffer body part 1 is constant, and the thickness of one end of the thickened part 2 close to the buffer body part 1 is equal to the thickness of the buffer body part 1. Since the thickness of the pole core body part 42 in the first direction is constant, the buffer body part 1 with constant thickness can better adapt to the pole core body part 42, and the gaps of the plurality of electrode pieces at the pole core body part 42 are uniformly distributed. The thickness of one end of the thickened part 2 close to the buffer body part 1 is equal to the thickness of the buffer body part 1, so that the thickened part 2 and the buffer body part 1 can naturally transition, thereby better adapting to the connection between the pole core body part 42 and the thinning part 41, and the uniformity of the gaps of the plurality of electrode pieces in the first direction in the pole core 4 can be improved, so that the lithium ion can be better transmitted between the plurality of electrode pieces, and the charge-discharge performance and safety of the battery monomer 200 can be better improved.

[0068] It should be noted that the maximum thickness of the thickening portion 2 is the difference in thickness between the core body portion 42 and the thinning portion 41, and the specific thickness and other dimensions of the thickening portion 2 and the buffer body portion 1 are determined according to the specific size of the battery cell 200, which is not limited in the present application.

[0069] In some embodiments of the present application, as shown in Figures 1-4 As shown in the direction from the buffer body portion 1 to the thickening portion 2, at least one side surface of the thickening portion 2 in the thickness direction is inclined to form a thickening surface 21 facing away from the other side in the thickness direction. In this way, the thickness of the thickening portion 2 gradually increases in the direction from the buffer body portion 1 to the thickening portion 2, which is reasonable in structure and easy to implement.

[0070] Each thickening surface 21 of each thickening portion 2 can be one, the side surface of the thickening portion 2 in the thickness direction close to the pole core 4 is inclined to form a thickening surface 21 facing away from the shell 3, or the side surface of the thickening portion 2 in the thickness direction away from the pole core 4 is inclined to form a thickening surface 21 close to the shell 3.

[0071] Of course, each thickening surface 21 of each thickening portion 2 can also be two, at this time, the side surface of the thickening portion 2 in the thickness direction close to the pole core 4 is inclined to form one thickening surface 21 facing away from the shell 3, and the side surface of the thickening portion 2 in the thickness direction away from the pole core 4 is inclined to form another thickening surface 21 close to the shell 3.

[0072] In some embodiments of the present application, as shown in Figures 1-4 The thickening surface 21 is a plane, an arc surface or a stepped surface. In this way, the thickness of the thickening portion 2 gradually increases in the direction from the buffer body portion 1 to the thickening portion 2, which is reasonable in structure design. The plane, arc surface or stepped surface of the thickening surface 21 is regular in shape, easy to implement, and also convenient for processing and production.

[0073] In some embodiments of the present application, as shown in Figures 5-9 The buffer body portion 1 is provided with a through hole 11 penetrating through the buffer body portion 1 in the thickness direction of the buffer body portion 1. The shell 3 of the battery cell 200 is provided with an electrolyte for the migration of lithium ions to realize the charging and discharging function of the battery cell 200. The buffer body portion 1 is provided with a through hole 11, which is conducive to the infiltration and circulation of the electrolyte, thereby improving the transmission effect of lithium ions in the battery cell 200, and further improving the charging and discharging performance of the battery cell 200. At the same time, it can also reduce the material and weight of the buffer piece 100, which is helpful to realize the lightweight design of the battery cell 200 and reduce the cost of the buffer piece 100 and the battery cell 200. In addition, the through hole 11 is arranged on the buffer body portion 1, which does not affect the thickening portion 2, and therefore does not affect the improvement effect of the buffer piece 100 on the gap between the multiple electrode plates at the thinning portion 41.

[0074] In some embodiments of the utility model, as shown in Figures 5-9 The distance between the inner side wall of the through hole 11 and the outer side wall of the buffer body part 1 is a, and a satisfies: 3mm≤a≤10mm, for example, a can be 3mm, 5mm, 7mm, 10mm. The buffer piece 100 is a rectangular sheet, and the through hole 11 is a rectangular hole corresponding to the buffer piece 100. The structure is simple, easy to realize, and convenient for processing and production. If a<3mm, the distance between the inner side wall of the through hole 11 and the outer side wall of the buffer body part 1 is too small, and the buffer body part 1 is prone to breakage, which affects the structural stability of the buffer piece 100, thereby affecting the stability of the thickening part 2 between the thinning part 41 and the shell 3. If a>10mm, the size of the through hole 11 is too small, which affects the infiltration and circulation effect of the electrolyte.

[0075] Therefore, 3mm≤a≤10mm can ensure the structural strength of the buffer piece 100, thereby ensuring the improvement effect of the buffer piece 100 on the gap between the multiple electrode sheets at the thinning part 41, and also ensuring the infiltration and circulation of the electrolyte, thereby improving the transmission effect of lithium ions in the battery monomer 200, and further improving the charge and discharge performance of the battery monomer 200.

[0076] In some embodiments of the utility model, as shown in Figures 5-9 The through hole 11 is one, and the side of the through hole 11 facing the thickening part 2 is open. The thickening part 2 is used for plugging the open mouth of the through hole 11. The structure is simple, easy to realize, and convenient for processing and production. It will not affect the thickening part 2, so it will not affect the improvement effect of the buffer piece 100 on the gap between the multiple electrode sheets at the thinning part 41. At the same time, it is helpful to enlarge the size of the through hole 11, thereby facilitating the improvement of the infiltration and circulation effect of the electrolyte, and further improving the transmission effect of lithium ions in the battery monomer 200, and improving the charge and discharge performance of the battery monomer 200.

[0077] In some embodiments of the utility model, as shown in Figures 5-9 The through hole 11 is a plurality of spaced through holes. It can enhance the structural strength of the buffer body part 1, thereby enhancing the stability and reliability of the thickening part 2 between the pole core 4 and the shell 3, and further ensuring the improvement effect of the buffer piece 100 on the gap between the multiple electrode sheets at the thinning part 41. At the same time, the plurality of through holes 11 can ensure the size of the total area of the through hole 11, thereby facilitating the improvement of the infiltration and circulation effect of the electrolyte, and further improving the transmission effect of lithium ions in the battery monomer 200, and improving the charge and discharge performance of the battery monomer 200. As shown in the example, Figure 8 The through hole 11 is a circular hole, and the plurality of through holes 11 are arranged in a matrix along the length direction and the width direction of the buffer body part 1. The structure is simple and regular, easy to realize, and convenient for processing and production.

[0078] In some embodiments of the utility model, the insulation resistance of buffer piece 100 is greater than or equal to 500MΩ, which can ensure the insulation performance of buffer piece 100, so that buffer piece 100 can replace the insulating film, avoiding the repeated setting of buffer piece 100 and insulating film outside the pole core 4, thereby effectively reducing the material cost.

[0079] In some embodiments of the utility model, the heat conductivity of buffer piece 100 is less than or equal to 0.03W / (m·℃), which can ensure the heat insulation performance of buffer piece 100, when one of the pole cores 4 occurs thermal runaway, buffer piece 100 can play a role in heat insulation and flame retardation, avoiding heat transfer to the adjacent pole core 4 or to the outside of the shell 3, thereby effectively improving the safety performance of the battery monomer 200.

[0080] In some embodiments of the utility model, at least one side of the thickness direction of buffer piece 100 is provided with a coating for bonding with the shell 3 or the pole core 4. The connection stability between buffer piece 100 and shell 3 or pole core 4 can be ensured, thereby the stability and reliability of thickening part 2 between pole core 4 and shell 3 can be enhanced, and the improvement effect of buffer piece 100 on the gap between the multiple electrode plates at the thinning part 41 can be ensured. At the same time, the assembly difficulty of buffer piece 100 can be reduced, the operation of bonding is simple and low in cost, which can effectively improve the assembly efficiency of battery monomer 200 and is conducive to reducing the cost.

[0081] In some embodiments of the utility model, buffer piece 100 is polyethylene, polypropylene, polystyrene, ethylene-vinyl acetate copolymer resin, ethylene-propylene rubber, silicone rubber or aerogel. The material of buffer piece 100 is simple, easy to obtain and convenient for processing and production. The structural strength, insulation performance and heat insulation performance of buffer piece 100 can be ensured, and buffer piece 100 also has elasticity, thereby realizing the buffering and protection effect of buffer piece 100 on battery monomer 200.

[0082] In some embodiments of the utility model, as shown in Figure 2 and Figure 4 Buffer piece 100 is located on at least one side of the pole core 4 along the second direction, and the second direction is perpendicular to the first direction. Thus, buffer piece 100 can protect the pole core 4 in the second direction, which can effectively fill the gap between the thinning part 41 and the shell 3, so that the multiple electrode plates in the pole core 4 can be better attached at the thinning part 41, which is conducive to improving the uniformity and transmission effect of lithium ions between the multiple electrode plates. At the same time, buffer piece 100 can also play a buffering role, absorbing the thickness change of pole core 4 in the second direction during the charging and discharging process, thereby avoiding the uneven deformation of pole core 4, and further prolonging the service life of battery monomer 200.

[0083] In some embodiments of the utility model, as shown in Figure 7 The buffer piece 100 can protect the pole core 4 in the third direction, effectively fill the gap between the thinning portion 41 and the shell 3, make the plurality of pole pieces in the pole core 4 better adhere at the thinning portion 41, and be beneficial to improve the uniformity and transmission effect of lithium ion extraction and embedding between the plurality of pole pieces. Meanwhile, the buffer piece 100 can also play a buffering role, absorb the thickness change of the pole core 4 in the third direction in the charging and discharging process, so that the uneven deformation of the pole core 4 can be avoided, and the service life of the battery monomer 200 is beneficial to prolong.

[0084] In some embodiments of the utility model, as shown in Figure 7 The first direction is the height direction of the battery monomer 200, that is, the positive and negative poles of the battery monomer 200 are arranged at one end or both ends of the battery monomer 200 along the first direction. The second direction is the width direction of the battery monomer 200, and the pole core 4 is arranged along the second direction, that is, the thickness direction of the pole core 4 is the second direction. The third direction is the length direction of the battery monomer 200, that is, the length direction of the pole core 4 is the third direction. In this way, the direction is set, so that the buffer piece 100 can be matched with the structure of the pole core 4, the position of the buffer piece 100 in the battery monomer 200 is reasonable, so that the buffer piece 100 can effectively fill the gap between the thinning portion 41 and the shell 3.

[0085] In some embodiments of the utility model, the first direction is the length direction of the battery monomer 200, the second direction is the height direction of the battery monomer 200, and the third direction is the width direction of the battery monomer 200. In this way, the direction is set, so that the buffer piece 100 can be matched with the structure of the pole core 4, the position of the buffer piece 100 in the battery monomer 200 is reasonable, so that the buffer piece 100 can effectively fill the gap between the thinning portion 41 and the shell 3.

[0086] The battery monomer 200 according to the embodiments of the utility model is described below.

[0087] The battery monomer 200 according to the embodiments of the utility model comprises a shell 3, a pole core 4 and the above-mentioned buffer piece 100,

[0088] Specifically, as shown in Figures 1-4As shown, the electrode core 4 is disposed within the housing 3. The electrode core 4 has a thinned portion 41 and an electrode core body portion 42. At least one end of the electrode core body portion 42 along the first direction has the thinned portion 41. The buffer member 100 is disposed within the housing 3 and includes a buffer body portion 1 and a thickened portion 2. The buffer body portion 1 is adapted to be located between the electrode core body portion 42 and the inner wall of the housing 3. At least one end of the buffer body portion 1 along the first direction is connected to the thickened portion 2. The thickened portion 2 is adapted to be located between the thinned portion 41 and the housing 3. The thickness of the thickened portion 2 is greater than or equal to the thickness of the buffer body portion 1.

[0089] According to the embodiment of the present invention, the battery cell 200, by placing a buffer 100 between the electrode core 4 and the housing 3, and simultaneously connecting at least one end of the buffer body 1 along the first direction to a thicker portion 2, the thicker portion 2 is adapted to be located between the thinned portion 41 and the housing 3, which can effectively fill the gap between the thinned portion 41 and the housing 3, so that the multiple electrodes in the electrode core 4 can be better fitted at the thinned portion 41. This is beneficial to improving the uniformity and transport effect of lithium ion extraction and insertion between the multiple electrodes, thereby reducing the possibility of lithium dendrite growth in the thinned portion 41 and avoiding safety problems such as lithium plating in the electrode core 4, thus effectively improving the charge and discharge performance and safety of the battery cell 200. It is also beneficial to reduce expansion force in the later stages of life, thereby reducing the increase in internal resistance of the battery cell 200 caused by side reactions at the end of life.

[0090] The battery pack according to an embodiment of the present invention includes: the above-mentioned battery cell 200.

[0091] According to the battery pack of this utility model embodiment, by placing a buffer 100 between the electrode core 4 and the housing 3, and simultaneously connecting at least one end of the buffer body 1 along the first direction to a thicker portion 2, the thicker portion 2 is adapted to be located between the thinned portion 41 and the housing 3. This effectively fills the gap between the thinned portion 41 and the housing 3, allowing the multiple electrode sheets in the electrode core 4 to better fit at the thinned portion 41. This improves the uniformity and transport effect of lithium ion extraction and insertion between the multiple electrode sheets, thereby reducing the possibility of lithium dendrite growth in the thinned portion 41 and avoiding safety issues such as lithium plating in the electrode core 4. Consequently, it effectively improves the charge and discharge performance and safety of the individual cell 200, and thus improves the safety and reliability of the battery pack. It also helps to reduce expansion force in the later stages of the battery life, thereby reducing the increase in internal resistance of the individual cell 200 caused by side reactions at the end of the battery life.

[0092] The electrical equipment according to an embodiment of the present invention includes: the battery pack described above.

[0093] According to the power equipment of the embodiment of the utility model, through the buffer piece 100 is established between the pole core 4 and the shell 3, simultaneously make the buffer body part 1 connect with the thickening 2 of greater thickness in at least one end of two ends along the first direction, the thickening 2 is suitable for between the thinning part 41 and the shell 3, can effectively supplement the gap between the thinning part 41 and the shell 3, make the multiple pole pieces in the pole core 4 realize better fit at the thinning part 41, be favorable to improve the uniformity and transmission effect of lithium ion between multiple pole pieces and extricate and embed, can reduce the possibility of lithium dendrite growth of thinning part 41 and avoid the safety problem such as lithium precipitation of pole core 4, and then can effectively improve the charge-discharge performance and safety of the battery cell 200, and then can improve the safety and reliability of battery pack and power equipment. Also be favorable to reduce the expansion force in the later life, thereby reducing the internal resistance growth of battery cell 200 by side reaction in the end of life.

[0094] Other configurations of the battery cell 200 according to the embodiment of the utility model, such as the pole 5, the electrode sheet, the positive electrode sheet, the negative electrode sheet and the diaphragm, are known to those skilled in the art, and will not be described in detail here.

[0095] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "exemplary embodiment", "example", "specific example" or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In the present specification, the exemplary description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0096] Although the embodiments of the utility model have been shown and described, those skilled in the art can understand that various changes, modifications, replacements and variations can be made to these embodiments without departing from the principles and purposes of the utility model, and the scope of the utility model is defined by the claims and their equivalents.

Claims

1. A cushioning element characterized by, A battery cell includes a shell and a pole core, the pole core is arranged in the shell, the pole core has a thinning portion and a pole core body portion, the pole core body portion has the thinning portion at least at one end in a first direction, and a buffer member is arranged in the shell and includes: a buffer body portion adapted to be located between the pole core body portion and an inner wall of the shell; a thickening portion connected to at least one end of the buffer body portion in the first direction, the thickening portion is adapted to be located between the thinning portion and the shell, and a thickness of the thickening portion is greater than or equal to a thickness of the buffer body portion.

2. The bumper of claim 1, wherein In a direction from the buffer body portion to the thickening portion, the thickness of the thickening portion gradually increases.

3. The bumper of claim 1, wherein In the first direction, the thickness of the buffer body portion is constant, and the thickness of the thickening portion at one end close to the buffer body portion is equal to the thickness of the buffer body portion.

4. The bumper of claim 1, wherein In the direction from the buffer body portion to the thickening portion, at least one side of the thickening portion in the thickness direction is inclined to form a thickening surface facing away from the other side of the thickness direction.

5. The bumper of claim 4, wherein, The thickening surface is a plane, an arc surface or a stepped surface.

6. The bumper of claim 1, wherein The buffer body portion is provided with a through hole penetrating through the buffer body portion in the thickness direction of the buffer body portion.

7. The bumper of claim 6, wherein, The through hole is one, The distance between the inner side wall of the through hole and the outer side wall of the buffer body portion is a, and a satisfies: 3mm≤a≤10mm; Or, one side of the through hole facing the thickening portion is open, and the thickening portion is used to block the open port of the through hole.

8. The bumper of claim 6, wherein, The through hole is a plurality of through holes arranged at intervals.

9. The bumper of claim 1, wherein, The insulation resistance of the buffer member is greater than or equal to 500MΩ. And / or, the thermal conductivity of the buffer member is less than or equal to 0.03W / (m·℃).

10. The bumper of claim 1, wherein At least one side of the buffer member in the thickness direction is provided with a coating for bonding with the shell or the pole core.

11. The bumper of claim 1, wherein The buffer member is a polyethylene member, a polypropylene member, a polystyrene member, an ethylene-vinyl acetate copolymer resin member, an ethylene-propylene-diene rubber member, a silicone rubber member or an aerogel member.

12. The bumper of claim 1, wherein, The buffer member is located at least on one side of the pole core in a second direction perpendicular to the first direction.

13. The bumper member of claim 12, wherein, The buffer member is arranged at least on one side of the pole core in a third direction, and the first direction, the second direction and the third direction are perpendicular to each other.

14. The bumper of claim 13, wherein, The first direction is the height direction of the battery cell, the second direction is the width direction of the battery cell, and the third direction is the length direction of the battery cell.

15. The bumper of claim 13, wherein, The first direction is the length direction of the battery cell, the second direction is the height direction of the battery cell, and the third direction is the width direction of the battery cell.

16. An electrochemical cell, characterized by The battery cell includes: a shell; a pole core arranged in the shell, the pole core has a thinning portion and a pole core body portion, the pole core body portion has the thinning portion at least at one end in a first direction; The cushion according to any one of claims 1-15, which is provided in the case and includes a cushion body portion and a thickened portion, the cushion body portion is adapted to be located between the core body portion and the inner wall of the case, the thickened portion is connected to at least one of two ends of the cushion body portion in the first direction, the thickened portion is adapted to be located between the thinned portion and the case, the thickness of the thickened portion is greater than or equal to the thickness of the cushion body portion, and the thickness of the thickened portion gradually increases in the direction from the cushion body portion to the thickened portion.

17. A battery pack, characterized by Comprising: The battery cell according to claim 16, which is a plurality.

18. An electrical device, characterized by Comprising the battery pack according to claim 17.

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