Battery monomer, battery and power-consuming device

Abstract

The present application relates to a battery cell, a battery and an electrical device. The battery cell comprises: a housing having a receiving cavity; a battery cell received in the receiving cavity, one end of the battery cell having a pole ear; and a busbar, comprising a busbar body, a bending portion and a connecting piece, the busbar body being arranged at one end of the battery cell having the pole ear and being electrically connected to the pole ear; the connecting piece being arranged on the housing and being electrically connected to the housing; the bending portion comprising a first connecting sub-portion, a second connecting sub-portion and at least two layers of folding sub-portions folded in a Z shape between the first connecting sub-portion and the second connecting sub-portion, the first connecting sub-portion being electrically connected to the busbar body, and the second connecting sub-portion being electrically connected to the connecting piece; wherein the first connecting sub-portion and the surfaces of the folding sub-portions adjacent thereto facing each other are at least partially in contact, the second connecting sub-portion and the surfaces of the folding sub-portions adjacent thereto facing each other are at least partially in contact, and the surfaces of the folding sub-portions of each adjacent layer are at least partially in contact.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a battery cell, a battery and an electrical device. Background Art

[0002] Lithium-ion batteries have high energy density, long cycle life, good rate performance and safety, and are green and environmentally friendly. They are important energy products for modern electronic products and power vehicles. Among them, steel-shell cylindrical lithium-ion batteries have uniform models, high production automation, good battery consistency, and convenient combination design. They are the first choice in the field of electronic products and power vehicles, and are being used on an increasingly large scale.

[0003] The battery is composed of multiple battery cells. The negative pole tabs of the cells in the battery cells need to be led out to the cover plate through the negative busbar, so that the cover plate serves as the negative pole of the battery cell. Traditionally, the negative busbar includes a disc body and a connecting piece integrally formed with the disc body. The disc body is used to be welded to the negative pole tab of the cell. The connecting piece is bent relative to the disc body to the side of the disc body away from the cell, and welded to the cover plate, so that the negative pole tab of the cell, the disc body, the connecting piece and the cover plate are electrically connected in sequence. However, since the connecting piece needs to be bent between the disc body, the width of the connection area between the connecting piece and the disc body is narrow, and the current flow path between the negative pole tab, the disc body, the connecting piece and the cover plate is far, resulting in a large resistance, a weak current capacity, and a poor ability to output large currents. Summary of the invention

[0004] Based on this, it is necessary to provide a battery cell, a battery and an electrical device that can reduce the resistance between the tab and the cover plate, improve the current capacity, and thus improve the ability to output large currents in order to solve the above problems.

[0005] In one aspect, the present application provides a battery cell, comprising:

[0006] The housing has a receiving cavity;

[0007] A battery cell is accommodated in the accommodation cavity, and one end of the battery cell has a tab; and

[0008] A busbar, comprising a busbar body, a bending portion and a connecting piece, wherein the busbar body is arranged at one end of the battery core having the pole ear and is electrically connected to the pole ear; the connecting piece is arranged on the shell and is electrically connected to the shell; the bending portion comprises a first connecting sub-portion, a second connecting sub-portion and at least two layers of folding sub-portions folded in a Z shape between the first connecting sub-portion and the second connecting sub-portion, the first connecting sub-portion is electrically connected to the busbar body, and the second connecting sub-portion is electrically connected to the connecting piece;

[0009] Among them, the first connecting sub-portion and the folding sub-portion adjacent thereto are at least partially in contact with each other's surfaces facing each other, the second connecting sub-portion and the folding sub-portion adjacent thereto are at least partially in contact with each other's surfaces facing each other, and the surfaces of the folding sub-portions of each two adjacent layers are at least partially in contact with each other.

[0010] In some embodiments, the housing includes a shell and a cover plate, the inner cavity of the shell is the receiving cavity, one end of the shell has an opening communicating with the receiving cavity, and the cover plate is disposed at the opening of the shell;

[0011] The end of the battery cell facing the cover plate has the pole ear, the busbar is located between the battery cell and the cover plate, and the connecting sheet is attached to a side of the cover plate facing the battery cell and is electrically connected to the cover plate.

[0012] In some embodiments, the outer shell includes a shell and an insulated pole arranged on the shell, the inner cavity of the shell is the receiving cavity, the end of the battery cell facing the pole has the pole ear, the busbar is located between the battery cell and the pole, one end of the pole extends into the receiving cavity and is electrically connected to the connecting piece.

[0013] In some embodiments, the battery cell further includes at least two magnetic components, which are arranged on the side of the second connecting sub-part facing away from the folding sub-part, between two adjacent folding sub-parts, and / or between the first connecting sub-part and an adjacent folding sub-part, and the two adjacent magnetic components attract each other, and when the temperature rises to a first preset range, the attraction between the two adjacent magnetic components gradually decreases.

[0014] In some embodiments, the number of the magnetic components is three, the first of the three magnetic components is arranged between two adjacent folding sub-sections, the second is arranged on the side of the second connecting sub-section away from the folding sub-section, and the third is arranged between the first connecting sub-section and the adjacent folding sub-section.

[0015] In some embodiments, the first magnetic component is located at the bending point of two adjacent folding sub-parts, the second magnetic component is located at an end of the second connecting sub-part close to the first magnetic component, and the third magnetic component is located at an end of the first connecting sub-part close to the first magnetic component.

[0016] In some embodiments, the battery cell further includes an expansion member, which is disposed between the second connecting sub-portion and an adjacent folding sub-portion, between two adjacent folding sub-portions, and / or between the first connecting sub-portion and an adjacent folding sub-portion, and each of the expansion members expands itself when the temperature rises to a second preset range.

[0017] In some embodiments, the expansion member disposed between the second connecting sub-portion and the adjacent folding sub-portion is located at a bending position between the second connecting sub-portion and the adjacent folding sub-portion.

[0018] In some embodiments, the expansion member disposed between two adjacent layers of the folded sub-portions is located at a bending position of two adjacent folded sub-portions.

[0019] In some embodiments, the expansion member disposed between the first connecting sub-portion and the adjacent folding sub-portion is located at a bending position between the first connecting sub-portion and the adjacent folding sub-portion.

[0020] In some embodiments, the first connecting sub-portion, at least part of the folding sub-portion and / or the second connecting sub-portion form a weak structure by means of grooves or thinning, and the weak structure is melted when the temperature rises to a third preset range.

[0021] On the other hand, the present application also provides a battery, comprising the battery cell as described in any one of the above embodiments.

[0022] On the other hand, the present application also provides an electrical device, comprising a battery cell or a battery as described in any of the above embodiments.

[0023] Compared with the prior art, this application has the following beneficial effects:

[0024] The above-mentioned battery cell, battery and electrical device, by designing the bending portion to include a first connecting sub-portion folded in a Z shape, at least two layers of folding sub-portions and a second connecting sub-portion, in addition to being electrically connected at the bending portion, the first connecting sub-portion and the folding sub-portion adjacent thereto also achieve electrical connection at a portion where the surfaces facing each other are in contact with each other; in addition to being electrically connected at the bending portion, the second connecting sub-portion and the folding sub-portion adjacent thereto also achieve electrical connection at a portion where the surfaces facing each other are in contact with each other; in addition to being electrically connected at the bending portion, the two adjacent layers of folding sub-portions also achieve electrical connection at a portion where the surfaces facing each other are in contact with each other, thereby greatly increasing the flow area between the pole ear of the battery cell and the shell, and shortening the flow path between the pole ear of the battery cell and the shell, thereby enhancing the flow capacity and improving the battery cell's ability to output large currents. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 A cross-sectional view of a battery cell in one embodiment of the present application;

[0026] Figure 2 for Figure 1 A partial enlarged view of the battery cell at position A shown;

[0027] Figure 3 for Figure 1 A schematic structural diagram of a busbar of a battery cell shown;

[0028] Figure 4 for Figure 3 A top view of the busbar shown;

[0029] Figure 5 for Figure 3 A cross-sectional view of the busbar shown (the magnetic element is in an attractive state);

[0030] Figure 6 for Figure 3 A cross-sectional view of the busbar shown (the magnetic element is in a non-attractive state);

[0031] Figure 7 This is a schematic structural diagram of a busbar in another embodiment of the present application;

[0032] Figure 8 for Figure 7 A top view of the busbar shown;

[0033] Fig. 9 for Figure 7 A cross-sectional view of the manifold shown (with the expansion element in an unexpanded state);

[0034] Fig.10 for Figure 7 A cross-sectional view of the manifold is shown (with the expansion element in the expanded state). DETAILED DESCRIPTION

[0035] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0036] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0037] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying 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 the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0038] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be 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 this application can be understood according to specific circumstances.

[0039] In the present application, unless otherwise clearly specified and limited, a first feature being “above” or “below” a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being “above”, “above”, and “above” a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being “below”, “below”, and “below” a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0040] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are for illustrative purposes only and are not intended to be the only implementation method.

[0041] An embodiment of the present application provides an electrical device that uses the following battery or battery cell as its power source. Specifically, the electrical device can be a vehicle, a mobile phone, a portable device, a laptop computer, a ship, a spacecraft, an electric toy, an electric tool, and the like. The vehicle can be a fuel vehicle, a gas vehicle, or a new energy vehicle, and the new energy vehicle can be a pure electric vehicle, a hybrid vehicle, or an extended-range vehicle, and the like; the spacecraft includes an airplane, a rocket, a space shuttle, and a spacecraft, and the like; the electric toys include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, and the like; the electric tools include metal cutting electric tools, grinding electric tools, assembly electric tools, and railway electric tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, and the like. The embodiments of the present application do not impose any special restrictions on the above-mentioned electrical devices.

[0042] The battery includes a box and a battery cell, and the battery cell is contained in the box. The box is used to provide a storage space for the battery cell. The box can adopt a variety of structures and a variety of shapes, such as a cylinder. In the battery, there can be multiple battery cells, and the multiple battery cells can be connected in series, in parallel, or in mixed connection. Mixed connection means that multiple battery cells are both connected in series and in parallel. Multiple battery cells can be directly connected in series, in parallel, or in mixed connection, and then the whole composed of multiple battery cells is contained in the box; of course, the battery can also be a battery module composed of multiple battery cells connected in series, in parallel, or in mixed connection, and multiple battery modules are then connected in series, in parallel, or in mixed connection to form a whole, and contained in the box. The battery can also include other structures. For example, the battery can also include a confluence component for realizing electrical connection between multiple battery cells. Each battery cell can be a secondary battery or a primary battery; it can also be a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, but is not limited to this.

[0043] The specific structure of the battery cell is described in detail below with reference to the accompanying drawings. Figure 1 is a cross-sectional view of a battery cell in an embodiment of the present application; Figure 2 for Figure 1 A partial enlarged view of the battery cell at position A shown; Figure 3 for Figure 1 A schematic structural diagram of a busbar 30 of a battery cell is shown; Figure 4 for Figure 3 A top view of the busbar 30 is shown; Figure 5 for Figure 3 A cross-sectional view of the busbar 30 shown (the magnetic element is in an attractive state); Figure 6 for Figure 3 A cross-sectional view of the busbar shown (the magnetic element is in a non-attractive state); Figure 7This is a schematic structural diagram of a busbar 30 in another embodiment of the present application; Figure 8 for Figure 7 A top view of the busbar 30 is shown; Fig. 9 for Figure 7 A cross-sectional view of the busbar 30 shown (the expansion member is in an unexpanded state); Fig.10 for Figure 7 The cross-sectional view of the busbar is shown (the expansion member is in an expanded state). For ease of description and understanding, the drawings only show structures related to the present application.

[0044] See also Figures 1 to 5 In an embodiment of the present application, a battery cell includes a shell 10, a battery cell 20 and a busbar 30. The shell 10 has a receiving cavity 15, and the battery cell 20 and the busbar 30 are both received in the receiving cavity 15 of the shell 10. One end of the battery cell 20 has a pole ear (not shown). The busbar 30 includes a disk body 31, a bending portion 33 and a connecting piece 35. The disk body 31 is disposed at one end of the battery cell 20 having the pole ear and is electrically connected to the pole ear. The connecting piece 35 is disposed on the shell 10 and is electrically connected to the shell 10. The bending portion 33 includes a first connecting sub-portion 332, a second connecting sub-portion 334 and at least two layers of folding sub-portions 336 folded in a Z shape between the first connecting sub-portion 332 and the second connecting sub-portion 334. The first connecting sub-portion 332 is electrically connected to the disk body 31, and the second connecting sub-portion 334 is electrically connected to the connecting sheet 35, so that the tabs of the battery cell 20, the disk body 31, the first connecting sub-portion 332, the folding sub-portions 336 of each layer, the second connecting sub-portion 334 and the connecting sheet 35 are electrically connected in sequence. Among them, the surfaces of the first connecting sub-portion 332 and the folding sub-portion 336 adjacent to it are at least partially in contact with each other, so that in addition to the electrical connection at the bend between the first connecting sub-portion 332 and the folding sub-portion 336 adjacent to it, the parts where the surfaces facing each other are in contact with each other are also electrically connected. The second connecting sub-portion 334 and the folding sub-portion 336 adjacent to it are at least partially in contact with each other, so that in addition to the electrical connection at the bend between the second connecting sub-portion 334 and the folding sub-portion 336 adjacent to it, the parts where the surfaces facing each other are in contact with each other are also electrically connected. The surfaces of the two adjacent layers of folded sub-parts 336 facing each other are at least partially in contact, so that in addition to the electrical connection between the two adjacent layers of folded sub-parts 336 at the bends, the portions where the surfaces facing each other contact each other are also electrically connected. This arrangement greatly increases the flow area between the tabs of the battery cell 20 and the housing 10, and shortens the flow path between the tabs of the battery cell 20 and the housing 10, thereby enhancing the flow capacity and improving the high current output capability of the battery cell.

[0045] In some embodiments, the housing 10 includes a shell 11 and a cover plate 13, and the inner cavity of the shell 11 is the above-mentioned receiving cavity 15. One end of the shell 11 has an opening (not shown) connected to the receiving cavity 15, and the cover plate 13 is covered at the opening of the shell 11, so that the cover plate 13 seals the opening of the shell 11. The end of the battery cell 20 facing the cover plate 13 has a pole ear, the busbar 30 is located between the battery cell 20 and the cover plate 13, and the connecting piece 35 is attached to the side of the cover plate 13 facing the battery cell 20 and is electrically connected to the cover plate 13, so that the pole ear of the battery cell 20, the plate body 31, the first connecting sub-portion 332, each layer of folding sub-portion 336, the second connecting sub-portion 334, the connecting piece 35 and the cover plate 13 are electrically connected in sequence, so as to realize the electrical connection between the pole ear of the battery cell 20 and the cover plate 13 of the shell 11, and then the cover plate 13 serves as an electrode terminal of the battery cell.

[0046] It should be noted that, in addition to serving as the electrode terminal of the battery cell and the opening of the sealing shell 11, the cover plate 13 can also play a role in squeezing the folded first connecting sub-portion 332, each layer of folding sub-portions 336 and the second connecting sub-portion 334, so that the first connecting sub-portion 332, each layer of folding sub-portions 336 and the second connecting sub-portion 334 are closer to each other and more tightly attached, thereby increasing the flow area, shortening the flow path, and improving the flow capacity.

[0047] Furthermore, a mounting hole (not marked in the figure) is provided at one end of the shell 11 facing away from the cover plate 13. The battery cell also includes a pole 50, which is insulated and mounted on the mounting hole of the shell 11. The end of the battery cell 20 facing the pole 50 also has a pole ear, and the pole ear on the end of the battery cell 20 facing the cover plate 13 and the pole ear on the end facing the pole 50 have opposite polarities, that is, one is the positive pole and the other is the negative pole. The pole 50 is electrically connected to the pole ear on the end of the battery cell 20 facing the pole 50, so that the pole 50 serves as another electrode terminal of the battery cell. In this way, the cover plate 13 and the pole 50 respectively serve as the two electrodes (i.e., the positive pole and the negative pole) of the battery cell, and together realize the input and output of electrical energy of the battery cell.

[0048] Specifically in the embodiment, the connecting piece 35 extends longitudinally along the circumferential direction of the cover plate 13, so that the connecting piece 35 is roughly in the shape of an arc (see Figure 4 ), which is beneficial to increase the contact area between the connecting piece 35 and the cover plate 13, on the one hand, enhancing the connection firmness between the connecting piece 35 and the cover plate 13, and on the other hand, increasing the flow area between the connecting piece 35 and the cover plate 13, further improving the flow capacity.

[0049] See also Figure 5 and Figure 6As shown, in some embodiments, the battery cell further includes at least two magnetic members 60, which are disposed on the side of the second connecting sub-portion 334 away from the folding sub-portion 336, between two adjacent folding sub-portions 336, and / or between the first connecting sub-portion 332 and an adjacent folding sub-portion 336. In each magnetic member 60, two adjacent magnetic members 60 attract each other, thereby pressing the second connecting sub-portion 334 and the folding sub-portion 336 between the two adjacent magnetic members 60, ensuring that the first connecting sub-portion 332, each layer of folding sub-portions 336, and the second connecting sub-portion 334 are closely attached to each other, and preventing the first connecting sub-portion 332, each layer of folding sub-portions 336, and the second connecting sub-portion 334 from separating from each other due to their own rebound, thereby increasing the flow area, shortening the flow path, and improving the flow capacity.

[0050] Furthermore, every two adjacent magnetic components 60 attract each other, and when the temperature rises to the first preset range, the attraction between the two adjacent magnetic components 60 gradually decreases until it is zero. In this way, when an abnormality occurs in the battery and causes the temperature to rise to the first preset range, the attraction between every two adjacent magnetic components 60 gradually decreases until it is zero. Since the attraction between the magnetic components 60 decreases or even becomes zero, the first connecting sub-portion 332, each layer of folding sub-portions 336, and the second connecting sub-portion 334 open to each other and gradually separate under the action of their own rebound, that is, gaps are generated between the first connecting sub-portion 332 and the adjacent folding sub-portion 336, between each layer of folding sub-portions 336, and between the second connecting sub-portion 334 and the adjacent folding sub-portion 336 (see Figure 6 As shown in the figure, the flow area is greatly reduced, the resistance is increased, and the heat generation is aggravated, so that the first connecting sub-section 332, each layer of folding sub-sections 336 and the second connecting sub-section 334 are easily melted and the circuit is cut off, which is beneficial to improve the safety of the battery.

[0051] Optionally, the material of the magnetic attraction member 60 may be a magnet. The first preset range may be 80° C.-150° C., and of course may be other temperature ranges, as long as they can meet the battery safety design requirements, and are not particularly limited here.

[0052] It should be noted that since resistance is inversely proportional to the flow area, the smaller the flow area, the greater the resistance, the greater the heat generation, and the easier it is to fuse; the smaller the filter area, the smaller the resistance, and the stronger the flow capacity. The fuse structure requires a small flow area, and on the contrary, a large flow area is required to achieve a large current output. Therefore, the fuse structure in the prior art cannot take into account both achieving a large current output and ensuring safety. In the battery cell of this embodiment, on the one hand, the first connecting sub-section 332, each layer of folding sub-section 336 and the second connecting sub-section 334 in the bending portion 33 are closely attached to each other, thereby increasing the flow area, reducing the resistance, and thus improving the battery cell's ability to output large currents; on the other hand, when the battery is abnormal and the temperature reaches the first preset temperature, the attraction between the magnetic suction parts 60 is reduced or even zero, so that the first connecting sub-section 332, each layer of folding sub-section 336 and the second connecting sub-section 334 in the bending portion 33 are separated from each other, thereby greatly reducing the flow area, increasing the resistance, and aggravating the heat generation, so that the first connecting sub-section 332, each layer of folding sub-section 336 and the second connecting sub-section 334 are easily melted, thereby cutting off the circuit and ensuring the safety of the battery. In other words, the battery cell of this embodiment has the characteristics of both strong ability to output large currents and strong safety.

[0053] Please continue to see Figure 5 and Figure 6 As shown, in one embodiment, the number of magnetic members 60 is three, the first magnetic member 60a of the three magnetic members 60 is arranged between two adjacent folding sub-portions 336, the second magnetic member 60 (b) is arranged on the side of the second connecting sub-portion 334 away from the folding sub-portion 336, and the third magnetic member 60c is arranged between the first connecting sub-portion 332 and the adjacent folding sub-portion 336. The first magnetic member 60a and the second magnetic member 60 (b) attract each other, and the first magnetic member 60a and the third magnetic member 60c also attract each other, so that under the action of the three magnetic members 60, the first connecting sub-portion 332 and each layer of the folding sub-portions 336 are pressed tightly to increase the flow area, shorten the flow path, and improve the flow capacity.

[0054] Optionally, the first magnetic component 60a is located at the bending point of two adjacent folding sub-portions 336, the second magnetic component 60 is located at one end of the second connecting sub-portion 334 close to the first magnetic component 60a, and the third magnetic component 60c is located at one end of the first connecting sub-portion 332 close to the first magnetic component 60a, so that the first magnetic component 60a is closer to the second magnetic component 60b and the third magnetic component 60c, and the attraction between the three is greater, ensuring that the first connecting sub-portion 332 and each layer of folding sub-portions 336 can be pressed tightly.

[0055] Of course, in other embodiments, the number of magnetic components 60 may be two, four, five, etc., which can be set according to the number of folding sub-parts 336 and is not limited here.

[0056] See also Figures 7 to 10 In some embodiments, the battery cell further includes an expansion member 70, and an expansion member 70 is provided between the second connecting sub-portion 334 and the adjacent folding sub-portion 336, between two adjacent folding sub-portions 336, and / or between the first connecting sub-portion 332 and the adjacent folding sub-portion 336. Each expansion member 70 expands itself when the temperature rises to the second preset range. In this way, when an abnormality occurs in the battery and causes the temperature to rise to the second preset range, each expansion member 70 expands, thereby stretching and separating the first connecting sub-portion 332, each layer of folding sub-portions 336, and the second connecting sub-portion 334 from each other, that is, gaps are generated between the first connecting sub-portion 332 and the adjacent folding sub-portion 336, between each layer of folding sub-portions 336, and between the second connecting sub-portion 334 and the adjacent folding sub-portion 336 (see Fig.10 As shown in the figure, the flow area is greatly reduced, the resistance is increased, and the heat generation is aggravated, so that the first connecting sub-section 332, each layer of folding sub-sections 336 and the second connecting sub-section 334 are easily melted to cut off the circuit, ensuring the safety of the battery.

[0057] It should be noted that the expansion member 70 may be made of an existing heat-expandable material, as long as it can achieve expansion of the expansion member 70 when the temperature reaches the second preset range to prop open the two adjacent folding sub-parts 336, the first connecting sub-part 332 and the folding sub-part 336, or the second connecting sub-part 334 and the folding sub-part 336. The second preset range may be 90°C-120°C, or other temperature ranges, as long as it can meet the battery safety design requirements, and is not particularly limited here.

[0058] Optionally, the expansion member 70 disposed between the second connecting sub-portion 334 and the adjacent folding sub-portion 336 is located at the bending portion between the second connecting sub-portion 334 and the adjacent folding sub-portion 336. In this way, when the second connecting sub-portion 334 and the adjacent folding sub-portion 336 are folded to form, a gap is formed at the bending portion due to the accumulation of materials at the bending portion. Therefore, the gap at the bending portion between the second connecting sub-portion 334 and the adjacent folding sub-portion 336 is used to accommodate the expansion member 70, so that the second connecting sub-portion 334 and the adjacent folding sub-portion 336 can be as close and close as possible, which is conducive to further increasing the flow area.

[0059] Optionally, the expansion member 70 disposed between two adjacent folding sub-sections 336 is located at the bend of the two adjacent folding sub-sections 336. In this way, when two adjacent layers of folding sub-sections 336 are folded to form, a gap exists at the bend due to the accumulation of materials at the bend. Therefore, the gap at the bend of the two adjacent layers of folding sub-sections 336 is used to accommodate the expansion member 70, so that the two adjacent layers of folding sub-sections 336 can be as close and close as possible, which is conducive to further increasing the flow area.

[0060] Optionally, the expansion member 70 disposed between the first connecting sub-portion 332 and the adjacent folding sub-portion 336 is located at the bend between the first connecting sub-portion 332 and the adjacent folding sub-portion 336. In this way, when the first connecting sub-portion 332 and the adjacent folding sub-portion 336 are folded to form, a gap is formed at the bend due to the accumulation of materials at the bend. Therefore, the gap at the bend between the first connecting sub-portion 332 and the adjacent folding sub-portion 336 is used to accommodate the expansion member 70, so that the first connecting sub-portion 332 and the adjacent folding sub-portion 336 can be as close and close as possible, which is conducive to further increasing the flow area.

[0061] Specifically in the embodiment, the first connecting sub-portion 332, at least part of the folding sub-portion 336 and / or the second connecting sub-portion 334 form a weak structure by slotting or thinning, and the weak structure is a fuse structure. When the temperature rises to a third preset range, the weak structure is melted. In this way, the setting of the weak structure is conducive to improving the temperature sensitivity of the melting, ensuring that the melting occurs and the circuit is cut off when the temperature rises to the third preset range, and further improving the safety of the battery.

[0062] When the battery is abnormal and the temperature rises to the first preset range or the second preset range, the attraction between the magnetic suction parts 60 is reduced or even zero or under the expansion of each expansion part 70, the first connecting sub-part 332, each layer of folding sub-parts 336 and the second connecting sub-part 334 are opened and gradually separated from each other, that is, gaps are generated between the first connecting sub-part 332 and the adjacent folding sub-part 336, between each layer of folding sub-parts 336, and between the second connecting sub-part 334 and the adjacent folding sub-part 336, thereby greatly reducing the flow area and increasing the resistance. As the resistance increases, the heat generation intensifies until the temperature rises to the third preset range, the weak structure is melted and the circuit is cut off, which greatly improves the safety of the battery.

[0063] Specific to Figure 7 and Figure 8In the embodiment shown, a hollow groove 37 is provided at the bending portion 33, so that a weak structure (i.e., a fuse structure) is formed at the bending portion 33, which can improve the temperature sensitivity of the bending portion 33 to be melted, and further improve the safety of the battery. Of course, in other embodiments, the bending portion of two adjacent layers of folding sub-portions 336 can also be thinned to form a weak structure (i.e., a fuse structure), which can also achieve the purpose of improving the temperature sensitivity of the bending portion 33 to be melted.

[0064] Of course, in other embodiments, the material of the first connecting sub-portion 332, at least part of the folding sub-portion 336 and / or the second connecting sub-portion 334 can be set to a low-melting-point conductive material to form a fuse structure. As long as it can ensure that the fuse occurs in time to cut off the circuit when the temperature rises to the third preset range, no special limitation is made here.

[0065] It should be noted that the busbar 30 is not limited to being arranged between the cover plate 13 and the battery cell 20 to realize the electrical connection between the tab of the battery cell 20 and the cover plate 13. In other embodiments, the busbar 30 may also be arranged between the battery cell 20 and the pole 50 to realize the electrical connection between the tab of the battery cell 20 and the pole 50. Specifically, the busbar body 31 of the busbar 30 is electrically connected to the tab on one end of the battery cell 20 facing the pole 50, and the connecting piece 35 of the busbar 30 is electrically connected to one end of the pole 50 located in the receiving cavity 15, so that the tab of the battery cell 20 is electrically connected to the pole 50, and the pole 50 is used as an electrode terminal of the battery cell.

[0066] That is to say, the tab at one end of the battery cell facing the cover plate can be electrically connected to the cover plate by using the above-mentioned busbar, and the tab at one end of the battery cell facing the pole can also be electrically connected to the pole by using the above-mentioned busbar.

[0067] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0068] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. A battery cell, characterized in that: include: The housing (10) has a receiving cavity (15); A battery cell (20) is accommodated in the accommodation cavity (15), and one end of the battery cell (20) has a pole ear; and A busbar (30), comprising a busbar body (31), a bending portion (33) and a connecting piece (35), wherein the busbar body (31) is arranged at one end of the battery cell (20) having the pole ear and is electrically connected to the pole ear; the connecting piece (35) is arranged on the housing (10) and is electrically connected to the housing (10); the bending portion (33) comprises a first connecting sub-portion (332), a second connecting sub-portion (334) and at least two layers of folding sub-portions (336) folded in a Z shape between the first connecting sub-portion (332) and the second connecting sub-portion (334); the first connecting sub-portion (332) is electrically connected to the busbar body (31), and the second connecting sub-portion (334) is electrically connected to the connecting piece (35); The surfaces of the first connecting sub-portion (332) and the folding sub-portion (336) adjacent thereto that face each other are at least partially in contact, the surfaces of the second connecting sub-portion (334) and the folding sub-portion (336) adjacent thereto that face each other are at least partially in contact, and the surfaces of the folding sub-portions (336) of every two adjacent layers that face each other are at least partially in contact; The battery cell further comprises at least two magnetic attracting members (60), the magnetic attracting members (60) being arranged on a side of the second connecting sub-portion (334) facing away from the folding sub-portion (336), between two adjacent folding sub-portions (336), and / or between the first connecting sub-portion (332) and an adjacent folding sub-portion (336), the two adjacent magnetic attracting members (60) attracting each other, and the attraction between the two adjacent magnetic attracting members (60) gradually decreases when the temperature rises to a first preset range; and / or The battery cell further comprises an expansion member (70), wherein the expansion member (70) is arranged between the second connecting sub-portion (334) and an adjacent folding sub-portion (336), between two adjacent folding sub-portions (336), and / or between the first connecting sub-portion (332) and an adjacent folding sub-portion (336), and each expansion member (70) expands itself when the temperature rises to a second preset range.

2. The battery cell according to claim 1, characterized in that: The housing (10) comprises a shell (11) and a cover plate (13); the inner cavity of the shell (11) is the receiving cavity (15); one end of the shell (11) has an opening communicating with the receiving cavity (15); and the cover plate (13) is arranged to cover the opening of the shell (11); The end of the battery cell (20) facing the cover plate (13) has the pole ear, the busbar (30) is located between the battery cell (20) and the cover plate (13), and the connecting sheet (35) is attached to a side of the cover plate (13) facing the battery cell (20) and is electrically connected to the cover plate (13).

3. The battery cell according to claim 1, characterized in that: The housing (10) comprises a shell (11) and a pole (50) insulated and arranged on the shell (11); the inner cavity of the shell (11) is the receiving cavity (15); one end of the battery cell (20) facing the pole (50) has the pole ear; the busbar (30) is located between the battery cell (20) and the pole (50); one end of the pole (50) extends into the receiving cavity (15) and is electrically connected to the connecting piece (35).

4. The battery cell according to claim 1, characterized in that: The number of the magnetic attraction members (60) is three, and the first of the three magnetic attraction members (60) is arranged between two adjacent folding sub-portions (336), the second is arranged on a side of the second connecting sub-portion (334) away from the folding sub-portion (336), and the third is arranged between the first connecting sub-portion (332) and an adjacent folding sub-portion (336).

5. The battery cell according to claim 4, characterized in that: The first magnetic component (60) is located at the bend of two adjacent folding sub-parts (336), the second magnetic component (60) is located at one end of the second connecting sub-part (334) close to the first magnetic component (60), and the third magnetic component (60) is located at one end of the first connecting sub-part (332) close to the first magnetic component (60).

6. The battery cell according to claim 1, characterized in that: The expansion member (70) disposed between the second connecting sub-portion (334) and the adjacent folding sub-portion (336) is located at a bending portion between the second connecting sub-portion (334) and the adjacent folding sub-portion (336).

7. The battery cell according to claim 1, characterized in that: The expansion member (70) disposed between two adjacent layers of the folding sub-portions (336) is located at the bending position of the two adjacent folding sub-portions (336).

8. The battery cell according to claim 1, characterized in that: The expansion member (70) disposed between the first connecting sub-portion (332) and the adjacent folding sub-portion (336) is located at a bending position between the first connecting sub-portion (332) and the adjacent folding sub-portion (336).

9. The battery cell according to any one of claims 1 to 8, characterized in that: The first connecting sub-portion (332), at least part of the folding sub-portion (336) and / or the second connecting sub-portion (334) form a weak structure by means of slotting or thinning, and the weak structure is melted when the temperature rises to a third preset range.

10. A battery, characterized in that: The invention comprises a battery cell as claimed in any one of claims 1 to 9.

11. An electrical device, characterized in that: The method comprises the battery cell according to any one of claims 1 to 9 or the battery according to claim 10.

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