Battery cell assembly and battery

Abstract

The utility model discloses a battery cell assembly and a battery. The battery cell assembly comprises a battery cell, the battery cell comprises a battery cell body, at least one groove with an opening in the first direction is formed in the first end of the battery cell body, the battery cell body comprises a first pole piece, a diaphragm and a second pole piece which are arranged in a stacked mode, and the grooves comprise a first groove located in the first pole piece, a second groove located in the diaphragm and a third groove located in the second pole piece; the first surface of the first pole piece and / or the second pole piece extends along the first direction to form a pole lug, and at least part of the structure of the pole lug is located in the groove; and a welding part formed by welding is arranged between the electrode adapter and the tab, and at least part of the structure of the welding part is located in the groove. According to the battery cell, the groove is formed in the battery cell body, and the welding part for welding the tab and the electrode adapter is positioned in the groove, so that the space occupied by welding between the tab and the electrode adapter is reduced, and the energy density of the battery cell is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, in particular to a battery cell assembly and a battery. Background Art

[0002] Due to many advantages such as high energy density, rechargeability and no pollution, lithium-ion batteries have become one of the most widely used batteries in consumer electronic products. With the diverse development needs of the consumer market, lithium-ion batteries have gradually developed into thin batteries with lightweight, small volume and small thickness.

[0003] The soft-pack battery is one of the current mainstream battery packaging methods. In its encapsulation process, the soft tab on the battery cell body is transferred and welded to the hard tab, and then the battery cell is encapsulated into a film shell formed by punching an aluminum-plastic film.

[0004] In order to improve the energy density of lithium-ion batteries, the tab welding plane of the multi-tab battery often needs to be bent to be less than the thickness dimension of the battery cell to meet the encapsulation requirements. However, for thinner batteries, the thickness of the battery cell is not sufficient to accommodate the tab welding plane, resulting in the tab exceeding the thickness dimension of the battery cell after bending. Summary of the Utility Model

[0005] The utility model aims to at least solve one of the technical problems existing in the prior art. For this reason, an object of the utility model is to provide a battery cell assembly and a battery, in which a groove is formed on the battery cell body, at least part of the welding part formed by welding the tab and the electrode adapter is located in the groove, and the tab and the electrode adapter are not bent, reducing the head space of the battery cell body occupied by the welding between the tab and the electrode adapter, and improving the energy density of the battery cell.

[0006] A battery cell assembly according to an embodiment of the utility model includes: a battery cell, including a battery cell body, at least one groove opening along a first direction is formed at a first end of the battery cell body, the battery cell body includes a first electrode plate, a separator and a second electrode plate which are stacked, the groove includes a first groove on the first electrode plate, a second groove on the separator and a third groove on the second electrode plate, a tab extends along the first direction on a first surface of the first electrode plate and / or the second electrode plate, and at least part of the tab structure is located in the groove; an electrode adapter, a welding part is formed by welding between the electrode adapter and the tab, and at least part of the welding part structure is located in the groove.

[0007] On the one hand, a groove is formed on the cell body. The tab connected to the cell body is welded to the electrode adapter. At least part of the welded part formed after welding is located in the groove, reducing the head space of the cell body occupied by the welding between the tab and the electrode adapter and improving the energy density of the cell. On the other hand, part of the length of the electrode adapter is located in the groove, reducing the occupation of the head space of the cell. During packaging, the electrode adapter does not need to be bent multiple times, simplifying the packaging process, with high packaging efficiency and fast product processing speed.

[0008] In some embodiments, the electrode adapter is parallel to the extending direction of the tab.

[0009] In some embodiments, the welded part is formed with a welding plane, and the included angle between the welding plane and the first direction is 0 - 20°.

[0010] In some embodiments, in the first direction, there is a first distance D1 between the end of the welded part close to the groove and the end face of the non-tab side of the first end of the cell body, where 0 ≤ D1 ≤ 8 mm.

[0011] In some embodiments, in the first direction, the end of the welded part close to the groove coincides with the edge of the corresponding side of the separator.

[0012] In some embodiments, in the first direction, the end of the welded part far from the groove extends beyond the end face of the non-tab side of the first end of the cell body.

[0013] In some embodiments, in the second direction perpendicular to the first direction, the distance between the edge of the electrode adapter and the edge of the tab is less than the distance between the edge of the tab and the side wall of the groove.

[0014] In some embodiments, the welded part formed by welding the tab extended from the first electrode plate to the electrode adapter extends beyond the end face of the second electrode plate far from the cell body side along the first direction away from the cell body.

[0015] According to some embodiments of the present invention, in the first direction, the depth of the groove is H1, where 0 ≤ H1 ≤ 10 mm, and / or, in the direction perpendicular to the first direction, the width of the groove is W1, where 2 mm ≤ W1 ≤ 16 mm.

[0016] According to some embodiments of the present utility model, the depth of the first groove is H2, where 0 ≤ H2 ≤ 10 mm; and / or, the width of the first groove is W2, where 2 mm ≤ W2 ≤ 16 mm; and / or, the depth of the second groove is H4, where 0 ≤ H4 ≤ 10 mm, and / or, the width of the second groove is W4, where 2 mm ≤ W4 ≤ 16 mm; and / or, the depth of the third groove is H3, where 0 ≤ H3 ≤ 10 mm; and / or, the width of the third groove is W3, where 4 mm ≤ W3 ≤ 18 mm.

[0017] According to some embodiments of the present utility model, in the first direction, the second spacing D2 between the non-grooved edge of the separator and the non-grooved edge of the first electrode tab does not exceed the third spacing D3 between the grooved edges of the separator and the first electrode tab.

[0018] According to some embodiments of the present utility model, in the first direction, a sealing area is provided at one end of the separator away from the battery cell body. The part of the sealing area within the second groove has a first sealing width M1, and the part of the sealing area outside the second groove has a second sealing width M2, and the first sealing width M1 exceeds the second sealing width M2.

[0019] According to some embodiments of the present utility model, in the first direction, there is a fourth spacing D4 between the end of the tab away from the battery cell body and the opening, where -6 mm ≤ D4 ≤ 2 mm.

[0020] An embodiment of the present utility model further provides a battery, including: the above-mentioned battery cell assembly; a housing assembly that wraps the battery cell assembly.

[0021] In some embodiments, the housing assembly forms a sealing edge structure on the side of the end face of the battery cell assembly with the tab.

[0022] In the first direction, there is a fifth spacing D5 between the end of the second electrode tab of the battery cell body close to the top sealing seal and the sealing edge structure, where D5 ≤ 2 mm.

[0023] The additional aspects and advantages of the present utility model will be partially given in the following description, partially become apparent from the following description, or be understood through the practice of the present invention.

[0024] For the battery of the present application, since the above-mentioned battery cell assembly is used, a groove is formed on the battery cell body, the tab connected to the battery cell body is welded to the electrode adapter, and at least part of the welded part formed after welding is located in the groove, reducing the head space of the battery cell body occupied by the welding between the tab and the electrode adapter, and the energy density of the battery is higher; at the same time, part of the length of the electrode adapter is located in the groove, reducing the occupation of the head space of the battery cell. During packaging, the electrode adapter does not need to be bent multiple times, simplifying the packaging process, with high packaging efficiency and fast product processing speed. Brief Description of the Drawings

[0025] The above and / or additional aspects and advantages of the present utility model will become obvious and easy to understand from the description of the embodiments in conjunction with the following drawings, wherein

[0026] Figure 1 is a schematic structural diagram of the battery cell assembly of the embodiment of the present utility model encapsulated inside the battery;

[0027] Figure 2 is a partial structural diagram of the battery cell assembly of the embodiment of the present utility model;

[0028] Figure 3 is another partial structural diagram of the battery cell assembly of the embodiment of the present utility model;

[0029] Figure 4 is a schematic structural diagram of the welding of the tab and the electrode adapter of the embodiment of the present utility model;

[0030] Figure 5 is a schematic structural diagram of the first pole piece of the embodiment of the present utility model;

[0031] Figure 6 is a schematic structural diagram of the separator of the embodiment of the present utility model;

[0032] Figure 7 is a schematic structural diagram of the second pole piece of the embodiment of the present utility model;

[0033] Figure 8 is a partial structural diagram of the part where the separator extends beyond the first pole piece of the embodiment of the present utility model;

[0034] Figure 9 is a schematic structural diagram of the formation of the sealing area on the separator of the embodiment of the present utility model.

[0035] Reference Signs:

[0036] 11 - Battery cell body; 111 - First pole piece; 1111 - First groove; 112 - Separator; 1121 - Second groove; 1122 - Sealing area; 113 - Second pole piece; 1131 - Third groove;

[0037] 12 - tab; 13 - groove;

[0038] 21 - electrode adapter; 22 - welding plane;

[0039] 3 - edge - sealing structure. Specific embodiments

[0040] The embodiments of the present invention will be described in detail below. The examples of the embodiments are shown in the drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the drawings are exemplary and are only used to explain the present invention and should not be construed as a limitation of the present invention.

[0041] Due to many advantages such as high energy density, rechargeability, and pollution - free, lithium - ion batteries have become one of the most widely used batteries in consumer electronic products. With the diverse development needs of the consumer market, lithium - ion batteries have gradually developed into thin - type batteries with lightweight, small volume, and small thickness.

[0042] The soft - package battery is one of the current mainstream battery packaging methods. In its encapsulation process, the soft tabs on the cell body are transferred and welded to the hard tabs, and then the cell is encapsulated into a film shell formed by punching an aluminum - plastic film.

[0043] In order to improve the energy density of lithium - ion batteries, the welding plane of the tabs of the multi - tab battery often needs to be bent to be less than the thickness dimension of the cell to meet the encapsulation requirements. However, for relatively thin batteries, the thickness of the cell is not sufficient to accommodate the welding plane of the tabs, resulting in the tabs exceeding the thickness dimension of the cell after bending.

[0044] In view of this, the present invention provides a cell assembly, a battery, and an electrical device. By forming a groove on the cell body, the tabs connected to the cell body are welded to the electrode adapter, and at least part of the welding part formed after welding is located in the groove, reducing the head space of the cell body occupied by the welding between the tabs and the electrode adapter and improving the energy density of the cell.

[0045] In the description of the present invention, it should be understood that 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", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation of the present invention.

[0046] In the description of the present utility model, the "first feature" and the "second feature" may include one or more of such features.

[0047] In the description of the present utility model, the meaning of "a plurality of" is two or more.

[0048] In the description of the present utility model, the first feature being "above" or "below" the second feature may include the first and second features being in direct contact, or may include the first and second features not being in direct contact but being in contact through additional features therebetween.

[0049] In the description of the present utility model, the first feature being "above", "over" and "on" the second feature includes the first feature being directly above and obliquely above the second feature, or merely indicating that the first feature has a higher horizontal height than the second feature.

[0050] Next, refer to Figures 1 to 9 to describe a cell assembly according to an embodiment of the first aspect of the present utility model.

[0051] Refer to Figures 1 to 3 , a cell assembly of the present utility model can be used in a battery. The cell assembly may include a cell and an electrode adapter 21. The cell may include a cell body 11 and a tab 12. A groove 13 is formed on the end face of the first end of the cell body 11. The groove 13 may be formed by removing a part of the structures of the positive electrode sheet, negative electrode sheet and separator of the cell respectively. The groove 13 opens in a first direction. There is at least one groove 13, and the number of the grooves 13 may match the number of the tabs 12. One end of the tab 12 is connected to the cell body 11, and the other end extends in the first direction, and at least a part of the structure of the tab 12 is located in the groove 13. In other words, the tab 12 may extend linearly along the opening direction of the groove 13, and the length of the tab 12 in the first direction may be greater than the depth of the groove 13. At this time, only a part of the structure of the tab 12 is in the groove 13, and the other part of the structure extends beyond the groove 13; or the length of the tab 12 in the first direction may be less than or equal to the depth of the groove 13. At this time, the tab 12 may be entirely in the groove 13. Of course, the present utility model does not limit this. The length of the tab 12 may be reasonably set according to actual needs to minimize the space occupied by the tab 12 at the head of the battery while ensuring the electrical connection requirements of the tab are met.

[0052] The electrode adapter 21 is welded to the tab 12. The electrode adapter 21 and the tab 12 have a welded portion formed by welding, and at least a part of the structure of the welded portion is located in the groove 13. For example, only a part of the structure of the welded portion is located in the groove 13, and the other part is outside the groove 13; or the welded portion may be entirely in the groove 13.

[0053] For example, the tab 12 can be a multi-layer flexible metal conductor extending from the positive and negative current collectors inside the battery cell. For example, the tab 12 can include a positive tab and a negative tab. Among them, the positive tab is a multi-layer flexible metal conductor extending from the positive current collector, and the negative tab is a multi-layer flexible metal conductor extending from the negative current collector. The tab 12 can have good bending performance to meet the deformation requirements when assembling the battery cell into batteries with different structures, while maintaining the stability of the electrical conduction path. The number of the grooves 13 can be set corresponding to the positive tab and the negative tab. For example, two grooves 13 can be provided on the battery cell body 11. The positive tab extends outward from one groove 13 and is welded to the electrode adapter 21 of the positive electrode of the battery, and the negative tab extends outward in the other groove 13 and is welded to the electrode adapter 21 of the negative electrode of the battery.

[0054] In this embodiment, by forming the groove 13 on the battery cell body 11, welding the tab 12 to the electrode adapter 21, and restricting at least part of the welded part formed after welding to be located in the groove 13, the groove 13 can be used to accommodate part of the lengths of the tab 12 and the electrode adapter 21 in the first direction, which can reduce the space occupied by the overall structure formed by welding the tab 12 and the electrode adapter 21 at the head of the battery. Moreover, since the tab 12 extends along the opening direction of the groove 13, it is possible to omit bending the tab 12, which is beneficial to reducing the number of bends of the whole formed by welding the tab 12 and the electrode adapter 21, thereby preventing the thickness of the area where the tab 12 and the electrode adapter 21 are located from exceeding the thickness of the battery cell body 11, and thus improving the energy density of the battery cell.

[0055] Among them, the first end of the battery cell body 11 can be the end where the tab 12 is provided; the first direction can be the direction extending outward from the tab 12 on the battery cell body 11, which can be determined according to the position of the tab 12 on the battery cell body 11 and the encapsulation method of the battery cell body 11 and the battery housing assembly. For example, referring to Figure 1 , in this embodiment, the tab 12 extends vertically away from the battery cell body 11 on the upper end surface of the battery cell body 11, and the battery cell assembly is vertically encapsulated into the battery housing assembly. At this time, the first end can be the upper end of the battery cell body 11, and the first direction can be the vertical direction. The groove 13 is opened on the top wall of the battery cell body 11 along the vertical direction. Or, in other embodiments, the tab 12 can also extend horizontally away from the battery cell body 11 on one side wall of the battery cell body 11, and the battery cell assembly is horizontally encapsulated into the battery housing assembly. At this time, the first end can be one end of the battery cell body 11 in the horizontal direction, and the first direction can be the horizontal direction. The groove 13 is opened on the side surface of the battery cell body 11 where the tab 12 is located along the horizontal direction.

[0056] The electrode adapter 21 can be a metal conductor with a relatively thick structure and good support performance, capable of withstanding large mechanical stresses and high currents passing through, and is suitable for application scenarios that require high power output. Through the electrical connection between the tab 12 and the electrode adapter 21, the tab 12 provides a connection inside the battery cell body 11, and the electrode adapter 21 serves as a transition to ensure a stable connection to the external circuit.

[0057] Understandably, the welding part can be entirely located within the groove 13, facilitating the encapsulation of the tab 12 and the electrode adapter 21. In fact, in some embodiments, since the groove 13 provides a receiving space, even if only part of the welding part is located within the groove 13, it can still meet the encapsulation process requirements of the tab 12 and the electrode adapter 21. For example, the end of the welding part away from the groove 13 can extend along the first direction and exceed the end face on the non-tab side of the first end of the battery cell body 11, that is, the welding part can extend beyond the groove 13. Since there is a fifth spacing D5 between the battery cell body 11 and the edge-sealing structure of the battery, as long as the distance that the welding part extends beyond the groove 13 is less than D5, the encapsulation process requirements can be met. The fifth spacing D5 will be described later.

[0058] In some embodiments, the electrode adapter 21 extends in a direction parallel to the tab 12. In other words, the electrode adapter 21 extends along the first direction, that is, in this embodiment, the process of bending the electrode adapter 21 can be omitted. In the traditional process, after the electrode adapter 21 is welded to the tab 12, it needs to be bent to a size smaller than the thickness of the battery cell body 11 to meet the encapsulation requirements, which greatly occupies the head space of the battery. And because the groove 13 is opened on the battery cell body 11, on the one hand, it provides a receiving space for the welding part of the tab 12 and the electrode adapter 21, and on the other hand, it also provides a receiving space for the electrode adapter 21. During encapsulation, arranging the electrode adapter 21 without bending and parallel to the first direction can also meet the encapsulation requirements, simplifying the process flow and preventing the battery appearance from having a bulge defect due to the bending of the electrode adapter 21 exceeding the thickness size of the battery cell body 11.

[0059] For the convenience of description, within the groove 13, the direction parallel to the first direction can be the depth direction of the groove 13, the inner wall of the groove 13 parallel to the first direction can be the side wall of the groove 13, and the inner wall perpendicular to the first direction can be the bottom wall of the groove 13.

[0060] Reference Figure 4, in some embodiments, the tab 12 may include a plurality of tab portions, which are stacked and arranged and formed into the tab 12 through a pressing process, that is, the tab 12 may be a structure with a certain thickness. A welding plane 22 is formed at the welding portion between the tab 12 and the electrode adapter 21, and the included angle between the welding plane 22 and the first direction may be 0 - 20°. During welding, the pressing positions of the plurality of tab portions 12 are attached to one end of the electrode adapter 21 and welded. The position where the tab 12 is attached to the electrode adapter 21 is the welding plane 22. Since the tab 12 may be a multi-layer flexible metal structure, during welding, some welding protrusions may appear on the welding portion along the side wall direction towards the groove 13. At this time, the welding plane 22 is the welding protrusion surface of the welding portion. Without affecting the encapsulation effect, the included angle between the welding plane 22 and the first direction may be 0 - 20°, that is, the included angle between the welding plane 22 and the length direction of the electrode adapter 21 may be 0 - 20°. For example, the included angle between the welding plane 22 and the first direction may be 0°, 1°, 2°, 3°, 4°, 5°, 6°, 7°, 8°, 9°, 10°, 11°, 12°, 13°, 14°, 15°, 16°, 17°, 18°, 19° or 20°. Of course, the present application does not limit this. The included angle between the welding plane 22 and the first direction can be reasonably selected within the above range according to actual needs.

[0061] In addition, in the traditional process of bending and encapsulating after welding the electrode adapter 21 and the tab 12, after bending, the welding plane 22 of the electrode adapter 21 and the tab 12 faces the cell body 11. During encapsulation, the welding protrusions of the welding portion may squeeze the cell body 11 and cause damage to the cell body 11. In this embodiment, the welding protrusions of the welding portion are arranged perpendicular to the first direction and will not cause damage to the cell body 11 during encapsulation.

[0062] Continue to refer to Figure 2 , in some embodiments, the depth direction of the groove 13 may be the first direction, the depth of the groove 13 may be H1, 0 ≤ H1 ≤ 10 mm, the width direction of the groove 13 may be perpendicular to the first direction, and the width of the groove 13 may be W1, 2 mm ≤ W1 ≤ 16 mm. The specific depth dimension and width dimension of the groove 13 are designed to meet the encapsulation requirements for encapsulating the cell assembly into the battery housing assembly.

[0063] For example, the depth H1 of the groove 13 can be 0.1 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm or 10 mm. Of course, the present application does not limit this, and the depth H1 of the groove 13 can be reasonably selected within the above range according to actual needs. In this way, it is avoided that the depth of the groove 13 is too small, resulting in a small space for accommodating the tab and the electrode adapter, and a large exposed part of the tab and the electrode adapter, occupying a large space. In addition, it is avoided that the depth of the groove 13 is too large, so that the groove 13 itself occupies a large space of the battery cell, resulting in a large loss of the active layer, which is not conducive to improving the battery energy density.

[0064] The width W1 of the groove 13 can be 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, 15 mm or 16 mm. Of course, the present application does not limit this, and the width W1 of the groove 13 can be reasonably selected within the above range according to actual needs.

[0065] In this way, it is avoided that the width of the groove 13 is too small, resulting in a small space for accommodating the tab and the electrode adapter, and a small width of the tab, which is not conducive to improving the current-carrying capacity at the tab. In addition, it is avoided that the width of the groove 13 is too large, so that the groove 13 itself occupies a large space of the battery cell, resulting in a large loss of the active layer, which is not conducive to improving the battery energy density.

[0066] Continue to refer to Figure 2 , based on some embodiments of the present invention, in the first direction, there is a first distance D1 between the end of the welding part close to the groove 13 and the end face of the battery cell body 11 having the tab 12, where 0 ≤ D1 ≤ 8 mm. The first distance D1 here can be the end of the welding position of the tab 12 and the electrode adapter 21 closest to the bottom wall of the groove 13, and the distance between the opening of the groove 13 on the battery cell body 11, that is, the first distance D1 can also be regarded as the length of the welding part in the groove 13 in the first direction. For example, the first distance D1 can be 0.1 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm or 8 mm. It should be noted that when designing the specific structural dimensions, the first distance D1 does not exceed the depth H1 of the groove 13.

[0067] Refer to Figure 3, Based on some embodiments of the present utility model, the length of the welding part can also exceed the first spacing D1, and the part exceeding the first spacing D1 extends in a direction away from the battery cell body 11, as long as the electrode adapter 21 and the tab 12 meet the encapsulation conditions. At this time, the encapsulation conditions can be: there is a fourth spacing D4 between the end of the tab 12 away from the battery cell body 11 and the opening, -6 mm ≤ D4 ≤ 2 mm, where the end of the tab 12 away from the battery cell body 11 can be the cutting edge obtained by cutting the pressed tab 12 during processing. When the cutting edge is located within the groove 13, the spacing from the opening is negative. For example, the fourth spacing D4 can be -6 mm, -5 mm, -4 mm, -3 mm, -2 mm, -1 mm or -0.1 mm. At this time, the welding part is entirely located within the groove 13. Or, when the cutting edge extends beyond the opening, the spacing between the cutting edge and the opening is positive. For example, the fourth spacing D4 can be 0.1 mm, 1 mm or 2 mm. At this time, the welding part can partially extend beyond the groove 13, and encapsulation can also be achieved. Of course, the cutting edge can also be exactly located at the opening, in which case the fourth spacing D4 is 0 and the welding part is entirely located within the groove 13.

[0068] Reference Figure 1 , Figure 5 , Figure 6 and Figure 7 , Based on some embodiments of the present utility model, the battery cell body 11 includes a first electrode tab 111, a separator 112, and a second electrode tab 113 stacked. The projections of the first electrode tab 111 and the second electrode tab 113 in the reference plane are located within the projection of the separator 112 in the reference plane. In Figure 1 the state shown, the reference plane can be a surface parallel to the front side and / or the rear side of the battery cell body 11. Among them, the first electrode tab 111 can be a positive electrode tab, and a positive tab can be connected to the positive electrode tab. The second electrode tab 113 can be a negative electrode tab, and a negative tab can be connected to the negative electrode tab.

[0069] It should be noted that, in order to improve the comprehensive performance of the battery, including energy density, charge-discharge efficiency, cycle life, and safety, etc., the length and width dimensions of the positive electrode sheet can be designed to be smaller than those of the negative electrode sheet. Among them, the negative electrode sheet, as the receiving end of lithium ions, needs to be able to quickly and fully embed or release lithium ions during the charge-discharge process. By increasing the area of the negative electrode sheet relative to the positive electrode sheet, more space can be provided for lithium ions to embed, thereby improving the electrochemical reaction efficiency and energy density of the battery; at the same time, in order to ensure that all lithium ions provided by the positive electrode can be effectively received by the negative electrode, the negative electrode needs to have sufficient capacity to accommodate these lithium ions. Therefore, designing the negative electrode sheet larger than the positive electrode sheet can ensure that during the battery cycle, the overall performance of the battery will not be limited due to insufficient negative electrode capacity; on the other hand, the volume change of the positive electrode material during the charge-discharge process may be more significant than that of the negative electrode material. Reducing the size of the positive electrode sheet helps to reduce the mechanical stress caused by volume expansion, thereby improving the cycle stability and service life of the battery; on the other hand, by adjusting the relative sizes of the positive and negative electrode sheets, the charge balance inside the battery can be optimized to ensure the smooth progress of the electrochemical reaction. A smaller positive electrode sheet can avoid the decline in battery performance caused by the inability of the positive electrode reaction rate to keep up during high-rate charge and discharge.

[0070] Since the length and width dimensions of the first electrode sheet 111 are smaller than those of the second electrode sheet 113, it is further defined that the welding part formed by welding the positive electrode tab extending from the first electrode sheet 111 to the electrode adapter 21 can extend along the first direction beyond the end face of the second electrode sheet 113 away from the battery cell body 11, so as to facilitate the connection between the electrode adapter 21 and the positive electrode tab extending from the smaller-sized first electrode sheet 111 and avoid interference between the welding part and the separator covering area, resulting in battery damage.

[0071] Furthermore, in the first direction, the end of the welding part close to the groove 13 coincides with the inner wall edge of the groove 13 facing the welding part. At this time, the edge of the groove 13 can be the outer edge of the separator covering area formed by the separator extending along the first direction, that is, the end of the welding part close to the groove coincides with the edge of the separator on the corresponding side. Compared with the traditional battery cell assembly without grooves, there is no need to set welding allowance between the welding part and the separator covering area in this embodiment, with simple design and convenient production.

[0072] Reference Figures 5 to 7, a first groove 1111 is formed on the first electrode tab 111, a second groove 1121 is formed on the separator 112, and a third groove 1131 is formed on the second electrode tab 113. Since the size of the positive electrode tab needs to be smaller than that of the negative electrode tab, during design, the depth dimension and width dimension of the third groove 1131 need to be restricted so as not to exceed the depth dimension and width dimension of the first groove 1111. At the same time, in the battery, since the separator 112 needs to play a role in physically isolating the positive electrode tab and the negative electrode tab from direct contact, the depth dimension and width dimension of the second groove 1121 are the same as those of the groove 13 and do not exceed the depth dimension and width dimension of the first groove 1111. The first electrode tab 111, the separator 112, and the second electrode tab 113 are processed in a certain order and number of layers through a stacking process or a winding process to form the battery cell body 11. At this time, a number of the first grooves 1111, the second grooves 1121, and the third grooves 1131 are stacked in sequence along the thickness direction of the battery cell body to form the groove 13. At the same time, the parts of the separator 112 that extend beyond the second electrode tab 113 extend towards the first electrode tab 111 and the second electrode tab 113 respectively to form the separator 112 covering area. Among them, the depth of the first groove 1111 can be H2, where 0 ≤ H2 ≤ 10 mm; for example, the depth H2 of the first groove 1111 can be 0.1 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, or 10 mm, and the width of the first groove 1111 can be W2, where 2 mm ≤ W2 ≤ 16 mm; for example, the width W2 of the first groove 1111 can be 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, 15 mm, or 16 mm;

[0073] The depth of the second groove 1121 is H4, where 0 ≤ H4 ≤ 10 mm; for example, the depth H4 of the second groove 1121 can be 0.1 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, or 10 mm, and the width of the second groove 1121 is W4, where 2 mm ≤ W4 ≤ 16 mm. For example, the width W4 of the second groove 1121 can be 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, 15 mm, or 16 mm.

[0074] The depth of the third groove 1131 can be H3, where 0 ≤ H3 ≤ 10 mm; the depth H3 of the third groove 1131 can be 0.1 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, or 10 mm.

[0075] The width of the third groove 1131 can be W3, where 4 mm ≤ W3 ≤ 18 mm. The width W3 of the third groove 1131 can be 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, 15 mm, 16 mm, 17 mm, or 18 mm. In this way, by designing the dimensions of the first groove 1111 and the third groove 1131, the dimensions of the groove 13 formed by the first groove 1111, the second groove 1121, and the third groove 1131 are defined, avoiding the width of the groove 13 being too small, resulting in a small space for accommodating the tab and the electrode adapter, leading to a small width of the tab and being unfavorable for improving the current-carrying capacity at the tab. Additionally, it avoids the width of the groove 13 being too large, causing the groove 13 itself to occupy a large space in the battery cell, resulting in a large loss of the active layer and being unfavorable for improving the battery energy density. It should be noted that when selecting specific dimensions, it is necessary to control the depth H2 of the first groove 1111 ≤ the depth H3 of the third groove 1131, and the width W2 of the first groove 1111 ≤ the width W3 of the third groove 1131.

[0076] Among them, the tab 12 can include: a positive tab extending from the first surface of the first electrode sheet 111 and a negative tab extending from the first surface of the second electrode sheet 113. Here, the first surface can be the surface parallel to the end face of the first end of the battery cell body 11 within the first groove 1111 and the third groove.

[0077] In some embodiments, in a second direction perpendicular to the first direction, the distance between the edge of the electrode adapter 21 and the edge of the tab 12 is less than the distance between the edge of the tab 12 and the side wall of the groove 13.

[0078] Here, the second direction can be a direction parallel to the width direction of the groove 13. The width of the electrode adapter 21 may exceed the width of the tab 12. At this time, along the second direction, the distance between the edge on one side of the electrode adapter 21 and the same-side edge of the tab 12 is restricted to be less than the distance from the same-side edge of the tab 12 to the same-side side wall of the groove 13. With such a setting, on the second direction, the two side edges of the electrode adapter 21 do not contact the inner wall of the groove 13, avoiding the electrode adapter 21 contacting other positions of the battery cell body 11 and causing a short circuit, and improving the safety of the battery.

[0079] Reference Figure 8, according to some embodiments of the present utility model, in the first direction, the second spacing D2 between the non-grooved edge of the separator 112 and the non-grooved edge of the first electrode tab 111 does not exceed the third spacing D3 between the grooved edge of the separator 112 and the grooved edge of the first electrode tab 111. During use, in the entire battery structure, the current passing through the tab 12 is the largest, resulting in the highest temperature at the tab 12. It is necessary to ensure that the separator 112 does not shrink into the battery cell body 11 under the action of high temperature, causing the first electrode tab 111 and the second electrode tab 113 to contact and short-circuit. Therefore, it is necessary to limit the spacing between the separator 112 and the first electrode tab 111 with a smaller geometric size, and only the thickness satisfying the third spacing D3 is required. The second spacing D2 can be set thinner, thereby improving the energy density of the battery.

[0080] Reference Figure 9 , further, during the processing of the battery cell, the process of forming the battery cell body 11 by making bags of the first electrode tab 111, the separator 112, and the second electrode tab 113 can be realized by the winding method or the stacking method. Taking the stacking method as an example, multiple layers of the first electrode tab 111 as the positive electrode tab, the separator 112, and the second electrode tab 113 as the negative electrode tab are laid and stacked in a certain order to form a multi-layer "positive electrode tab - separator - negative electrode tab" structure. The part of the separator 112 that exceeds the second electrode tab 113 extends towards the first electrode tab 111 and the second electrode tab 113 respectively to form a separator 112 covering area, and then the edges are fixed by methods such as hot pressing or ultrasonic welding. At this time, one end of the separator 112 covering area away from the battery cell body 11 forms a sealing area 1122.

[0081] Similarly, during use, in the entire battery structure, the current passing through the tab 12 is the largest, resulting in the highest temperature at the tab 12. It is necessary to ensure that the sealing area 1122 does not shrink and break under the action of high temperature. The part of the sealing area 1122 inside the second groove 1121 can have a first sealing width M1, and the part of the sealing area 1122 outside the second groove 1121 can have a second sealing width M2. The first sealing width M1 and the second sealing width M2 can refer to the widths on both sides of the corresponding position of the sealing area 1122 in the first direction. The first sealing width M1 exceeds the second sealing width M2, and it is only necessary to ensure that the width of the sealing area 1122 inside the groove 13 is sufficient.

[0082] The second aspect of the present utility model further provides a battery, which may include the above-mentioned battery cell assembly and a housing assembly. The housing assembly wraps the battery cell assembly. For example, the housing assembly can be an aluminum-plastic film.

[0083] The battery of this embodiment, due to the use of the battery cell assembly of the present utility model, forms a groove 13 on the battery cell body 11. The tab 12 connected to the battery cell body 11 is welded to the electrode adapter 21, and at least part of the welded part formed after welding is located in the groove 13, reducing the head space of the battery cell body 11 occupied by the welding between the tab 12 and the electrode adapter 21, and the energy density of the battery is higher. At the same time, part of the length of the electrode adapter 21 is located in the groove 13, reducing the occupation of the head space of the battery cell. During encapsulation, the electrode adapter 21 does not need to be bent multiple times, simplifying the encapsulation process, with high encapsulation efficiency and fast product processing speed.

[0084] Continuing to refer to Figure 1 , in some embodiments of the battery of the present utility model, a sealing edge structure 3 is formed on the end face side of the battery cell assembly with the tab 12. The sealing edge structure 3 directly affects the sealing performance, safety and reliability of the battery. The design of the sealing edge structure 3 needs to ensure that the electrolyte inside the battery does not leak, and at the same time, it should be able to withstand the mechanical stress of the battery under use and abuse conditions, such as expansion and external pressure. For example, the housing assembly may include an outer shell, and the sealing edge structure 3 may be a top seal. Polyvinyl chloride (PVC), polypropylene (PP) or other high-performance heat-sealing materials are selected as the sealing material, and the sealing material is melted and bonded with the outer shell of the battery cell assembly for encapsulation by using heat and pressure to form a top seal.

[0085] In the first direction within the outer shell, there is a fifth spacing D5 between the end of the second electrode plate 113 of the battery cell body 11 close to the top seal and the top seal, and D5 ≤ 2 mm, to avoid interference with the battery cell body when the sealing edge structure 3 seals the battery cell body 11, causing damage to the battery cell body 11. At the same time, it also ensures that there is enough installation space for the battery cell assembly inside the battery. For example, the fifth spacing D5 can be 1 mm, 1.5 mm or 2 mm.

[0086] The third aspect of the present utility model also provides an electrical device, which may include: a device main body and the above-mentioned battery. The device main body may include a battery compartment, and the battery is disposed in the battery compartment and electrically connected to the device main body. For example, a power supply interface may be provided in the battery compartment, and the battery may be connected to the power supply interface. Due to the use of the battery of the present utility model, the space at the head of the battery is fully utilized, the internal space utilization rate of the battery is improved, the energy density is increased, the battery life is extended, and the electrical device has a long service time.

[0087] It can be understood that the electrical device of the present application may be a mobile electronic device, an electric tool, a smart home device, an electric vehicle and an electric bicycle, a drone, a medical device, a photographic device, outdoor equipment, wireless headphones and Bluetooth speakers, and an energy storage system, etc., using the above-mentioned battery as a power source to supply energy to the electrical device.

[0088] In the description of this specification, the descriptions with reference to terms such as "one embodiment", "some embodiments", "schematic embodiments", "examples", "specific examples", or "some examples", etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present utility model. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. Although the embodiments of the present utility model have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and purposes of the present utility model, and the scope of the present utility model is defined by the claims and their equivalents.

Claims

1. A battery cell assembly, characterized in that, Comprising: A battery cell, including a battery cell body (11), at least one groove (13) that opens in a first direction is provided at a first end of the battery cell body (11), and the battery cell body (11) includes a first electrode tab (111), a separator (112), and a second electrode tab (113) that are stacked. The groove (13) includes a first groove (1111) on the first electrode tab (111), a second groove (1121) on the separator (112), and a third groove (1131) on the second electrode tab (113). An electrode tab (12) extends along the first direction on a first surface of the first electrode tab (111) and / or the second electrode tab (113), and at least a part of the structure of the electrode tab (12) is located within the groove (13). An electrode adapter (21), a welded portion formed by welding is provided between the electrode adapter (21) and the electrode tab (12), and at least a part of the structure of the welded portion is located within the groove (13).

2. The cell assembly according to claim 1, wherein The electrode adapter (21) is parallel to the extending direction of the electrode tab (12).

3. The cell assembly according to claim 1, wherein, The welded portion forms a welding plane (22), and the included angle between the welding plane (22) and the first direction is 0 - 20°.

4. A cell component according to claim 1, wherein In the first direction, there is a first distance D1 between an end of the welded portion close to the groove (13) and an end face of the first end of the battery cell body (11) on the non-electrode-tab side, where 0 ≤ D1 ≤ 8 mm.

5. A cell assembly according to claim 1, wherein In the first direction, an end of the welded portion close to the groove (13) coincides with an edge of the corresponding side of the separator.

6. The cell assembly according to claim 1, wherein, In the first direction, an end of the welded portion away from the groove (13) extends beyond the end face of the first end of the battery cell body (11) on the non-electrode-tab side.

7. A cell assembly according to claim 1, wherein In a second direction perpendicular to the first direction, the distance between an edge of the electrode adapter (21) and an edge of the electrode tab (12) is less than the distance between the edge of the electrode tab (12) and a side wall of the groove (13).

8. A cell assembly according to claim 1, wherein, The welded portion formed by welding the electrode tab (12) extending from the first electrode tab (111) and the electrode adapter (21) extends away from the battery cell body (11) along the first direction and exceeds the end face of the second electrode tab (113) on the side away from the battery cell body (11).

9. The cell assembly according to claim 1, wherein, In the first direction, the depth of the groove (13) is H1, where 0 ≤ H1 ≤ 10 mm, and / or In a direction perpendicular to the first direction, the width of the groove (13) is W1, where 2 mm ≤ W1 ≤ 16 mm.

10. A battery cell assembly according to claim 1, wherein the depth of the first groove (1111) is H2, where 0 ≤ H2 ≤ 10 mm; and / or the width of the first groove (1111) is W2, where 2 mm ≤ W2 ≤ 16 mm; and / or the depth of the second groove (1121) is H4, where 0 ≤ H4 ≤ 10 mm, and / or the width of the second groove (1121) is W4, where 2 mm ≤ W4 ≤ 16 mm; and / or The depth of the third groove (1131) is H3, where 0 ≤ H3 ≤ 10 mm; and / or, The width of the third groove (1131) is W3, where 4 mm ≤ W3 ≤ 18 mm.

11. A cell assembly according to claim 1, characterized in that, In the first direction, the second spacing D2 between the non-groove edge of the separator (112) and the non-groove edge of the first electrode tab (111) does not exceed the third spacing D3 between the groove edge of the groove (13) on the separator (112) and the groove edge of the groove (13) between the separator (112) and the first electrode tab (111).

12. A cell assembly according to claim 1, wherein, In the first direction, a sealing area (1122) is provided at one end of the separator (112) away from the battery cell body (11). The part of the sealing area (1122) within the second groove (1121) has a first sealing width M1, and the part of the sealing area (1122) outside the second groove (1121) has a second sealing width M2, and the first sealing width M1 exceeds the second sealing width M2.

13. A cell component according to claim 1, wherein, In the first direction, there is a fourth spacing D4 between the end of the tab (12) away from the battery cell body (11) and the opening, where -6 mm ≤ D4 ≤ 2 mm.

14. A battery, characterized in that, Comprising: The battery cell assembly according to any one of claims 1-13; A housing assembly that wraps the battery cell assembly.

15. A battery according to claim 14, wherein, The housing assembly forms a sealing edge structure (3) on the side of the end face of the battery cell assembly with the tab (12). In the first direction, there is a fifth spacing D5 between the end of the second electrode tab (113) of the battery cell body (11) close to the sealing edge structure (3) and the sealing edge structure (3), where D5 ≤ 2 mm.

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