Battery cell and battery module

Abstract

The application is an electric core and a battery module, and relates to the technical field of batteries. The electric core comprises a plurality of positive pole pieces, a plurality of negative pole pieces, a first connecting piece and a second connecting piece. The positive pole piece comprises a positive pole piece body and a positive pole lug, and the negative pole piece comprises a negative pole piece body and a negative pole lug. At least one of the positive pole lug and the negative pole lug is arranged in multiple groups, and the number of each group of the positive pole lug and the negative pole lug does not exceed a specified threshold. Each first welding position of the first connecting piece is welded with a group of the positive pole lug, and each second welding position of the second connecting piece is welded with a group of the negative pole lug. In the application, the multiple pole lugs are grouped and welded with the connecting piece, the number of the pole layers welded with the same welding position of the connecting piece is reduced, more pole lugs can be welded on the connecting piece, more layers of the pole pieces are arranged in the electric core, and the output power performance of the electric core is improved.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a battery cell and a battery module. Background Technology

[0002] With the rapid development of fields such as drones and small power equipment, users have increasingly higher requirements for the power performance of battery cells. Therefore, battery cells need to increase the number of stacked electrode layers to increase the current carrying area, thereby improving power performance.

[0003] In related technologies, the tabs of multi-layer electrodes are usually connected to the connectors using an ultrasonic welding process. However, the increase in the number of tab layers means that some tabs cannot be fully heated, which in turn leads to a higher risk of incomplete connection between some tabs and the connectors, thus limiting the improvement of the cell's power performance. Utility Model Content

[0004] This application provides a battery cell and a battery module, which can solve the aforementioned technical problems existing in related technologies. The technical solution is as follows:

[0005] In a first aspect, a battery cell is provided, the battery cell comprising a plurality of positive electrode plates, a plurality of negative electrode plates, a first connector, and a second connector;

[0006] Multiple positive electrode plates and multiple negative electrode plates are arranged alternately;

[0007] The positive electrode includes a positive electrode body and a positive electrode tab, the positive electrode tab being connected to a first edge of the positive electrode body. The negative electrode includes a negative electrode body and a negative electrode tab, the negative electrode tab being connected to a second edge of the negative electrode body. At least one of the positive electrode tab and the negative electrode tab is configured as multiple groups, and the number of positive electrode tabs in each group and the number of negative electrode tabs in each group do not exceed a specified threshold.

[0008] The first connector has multiple first welding points, each of which is welded to a set of positive tabs. The second connector has multiple second welding points, each of which is welded to a set of negative tabs.

[0009] In some possible implementations, the plurality of positive tabs are located on the same side of the plurality of positive electrode bodies. In the stacking direction of the positive tabs, the plurality of positive tabs are positioned opposite each other and opposite to the first connector. Positive tabs in the same group are adjacent to each other.

[0010] In any two sets of positive tabs, the length of the first set of positive tabs away from the first connector in the first direction is greater than the length of the second set of positive tabs close to the first connector in the first direction, and the portion of the first set of positive tabs protruding from the second set of positive tabs in the first direction is welded to the first welding position, wherein the first direction is a direction perpendicular to the stacking direction and the first edge.

[0011] In some possible implementations, the plurality of positive tabs are located on the same side of the plurality of positive electrode bodies. In the stacking direction of the positive tabs, there is overlap between all positive tabs in the same group. The first region in the overlapping region is not opposite to the positive tabs of other groups, and the first region is opposite to and welded to a first welding point of the first connector.

[0012] In some possible implementations, the first connector includes a first segment and a second segment connected to each other, the first segment extending along a first direction and the second segment extending along the stacking direction of the positive electrode tab, wherein the first direction is a direction perpendicular to the stacking direction and the first edge;

[0013] The multiple positive electrode tabs are all located on the same side of the multiple positive electrode bodies. Among the multiple sets of positive electrode tabs, at least one set of positive electrode tabs is opposite to and welded to the first welding part located in the first segment, and the remaining sets of positive electrode tabs are opposite to and welded to the first welding part located in the second segment.

[0014] In some possible implementations, the positive tabs in the same group are of the same size.

[0015] In some possible implementations, the first connector includes a first layer and a second layer welded together.

[0016] The first layer is opposite to the positive electrode tab and is used for welding to the positive electrode tab. The stiffness of the first layer is greater than that of the positive electrode tab.

[0017] The second layer is located on the side of the first layer away from the positive electrode tab and is used to connect to electronic components outside the battery cell. The stiffness of the second layer is greater than that of the first layer.

[0018] In some possible implementations, the plurality of negative tabs are located on the same side of the plurality of negative electrode bodies. In the stacking direction of the negative tabs, the plurality of negative tabs are positioned opposite each other and opposite to the first connector. Negative tabs in the same group are adjacent to each other.

[0019] In any two sets of negative tabs, the length of the first set of negative tabs farther from the second connector in the second direction is greater than the length of the second set of negative tabs closer to the second connector in the second direction, and the portion of the first set of negative tabs protruding from the second set of negative tabs in the second direction is welded to the second welding position, wherein the second direction is a direction perpendicular to the stacking direction and the second edge.

[0020] In some possible implementations, the plurality of negative tabs are located on the same side of the plurality of negative electrode bodies. In the stacking direction of the negative tabs, there is overlap between all negative tabs in the same group. The second region in the overlapping area is not opposite to the negative tabs of other groups, and the second region is opposite to and welded to a second welding part of the second connector.

[0021] In some possible implementations, the second connector of the negative electrode tab includes a third segment and a fourth segment connected to each other, the third segment extending along a second direction and the fourth segment extending along the stacking direction of the negative electrode tab, wherein the second direction is a direction perpendicular to the stacking direction and the second edge;

[0022] The multiple negative electrode tabs are all located on the same side of the multiple negative electrode sheet bodies. Among the multiple sets of negative electrode tabs, at least one set of negative electrode tabs is opposite to and welded to the second welding part located in the third section, and the remaining sets of negative electrode tabs are opposite to and welded to the second welding part located in the second section.

[0023] In some possible implementations, the negative electrode tabs in the same group are of the same size.

[0024] In some possible implementations, the second connector includes a third layer and a fourth layer welded together;

[0025] The third layer is opposite to the negative electrode tab and is used for welding to the negative electrode tab. The stiffness of the third layer is greater than that of the negative electrode tab.

[0026] The fourth layer is located on the side of the third layer away from the negative electrode tab and is used to connect to electronic components outside the battery cell. The stiffness of the fourth layer is greater than that of the third layer.

[0027] In some possible implementations, the specified threshold value ranges from 25 to 30.

[0028] In a second aspect, a battery module is provided, the battery module comprising the battery cells described in any one of the first aspects.

[0029] The beneficial effects of the technical solution provided in this application include at least the following:

[0030] In this application, each first welding point of the first connector is welded to a group of positive tabs, and each second welding point of the second connector is welded to a group of negative tabs. The number of positive tabs in each group and the number of negative tabs in each group do not exceed a specified threshold. That is, multiple tabs are welded to the connector in groups, which reduces the number of tab layers welded to the same welding point of the connector. This allows for the welding of more tabs on the connector, the arrangement of more layers of electrode sheets inside the cell, and the improvement of the cell's output power performance.

[0031] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This is an exploded schematic diagram of a battery cell provided in an embodiment of this application;

[0034] Figure 2 This is an exploded schematic diagram of a battery cell provided in an embodiment of this application;

[0035] Figure 3 This is a schematic diagram showing the position of the positive electrode tab and the first connector according to an embodiment of this application;

[0036] Figure 4 This is a schematic diagram showing the location of a battery cell according to an embodiment of this application;

[0037] Figure 5 This is an exploded schematic diagram of a battery cell provided in an embodiment of this application;

[0038] Figure 6 This is an exploded schematic diagram of a battery cell provided in an embodiment of this application;

[0039] Figure 7 This is a schematic diagram showing the position of the positive electrode tab and the first connector according to an embodiment of this application;

[0040] Figure 8 This is a schematic diagram showing the position of the negative electrode tab and the second connector according to an embodiment of this application;

[0041] Figure 9 This is a schematic diagram of the structure of a positive electrode and a negative electrode provided in an embodiment of this application;

[0042] Figure 10This is a schematic diagram of the connection between the electrode tab and the connector in related technologies.

[0043] Figure label:

[0044] 1. Positive electrode plate; 11. Positive electrode plate body; 12. Positive electrode tab;

[0045] 2. Negative electrode plate; 21. Negative electrode plate body; 22. Negative electrode tab;

[0046] 3. First connector; 30. First welding point; 31. First segment; 32. Second segment; 3a. First layer; 3b. Second layer;

[0047] 4. Second connector; 40. Second welding point; 41. Third section; 42. Fourth section; 4a. Third layer; 4b. Fourth layer;

[0048] 5. Insulating diaphragm;

[0049] 101. Electrode; 102. Connector.

[0050] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0051] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0052] With the rapid development of fields such as drones and small power equipment, users have increasingly higher requirements for the power performance of battery cells. Therefore, battery cells need to increase the number of stacked electrode layers to increase the current carrying area, thereby improving power performance.

[0053] In related technologies, refer to Figure 10 As shown, multiple tabs 101 are stacked, and connectors 102 are placed on one side of the multi-layer tabs 101. The connectors 102 and the multi-layer tabs 101 are connected together by ultrasonic welding process to achieve electrical connection.

[0054] The specific principle of ultrasonic welding is as follows: The ultrasonic device generates heat through high-frequency mechanical vibration at a certain position on the surface of the connector 102, which gradually melts the connector 102 and each layer of tab 101. The melted materials of the connector 102 and tab 101 fuse and re-solidify, thereby realizing the electrical conduction between the connector 102 and the tab 101.

[0055] Melting each layer of tab 101 involves heat consumption. Therefore, if the ultrasonic welding power is too low, the corresponding areas of tab 101 far from the connector 102 will not be heated and melted sufficiently, resulting in insufficient electrical connection or poor contact. If the ultrasonic welding power is too high, the tabs 101 near the connector 102 will absorb more heat and over-melt, leading to breakage and failure. Therefore, the ultrasonic welding process has certain limitations on the number of tab layers 101, and the number of tab layers cannot be continuously increased.

[0056] However, consumers have increasingly higher requirements for the power performance of battery cells. Battery cells need to increase the number of stacked electrode layers to increase the current carrying area and thus improve power performance. Currently, the connection method of connector 102 and tab 101 limits the number of electrode layers, which is not conducive to improving the power performance of battery cells.

[0057] This application provides a battery cell, referring to... Figure 1 As shown, the battery cell includes multiple positive electrode plates 1, multiple negative electrode plates 2, a first connector 3, and a second connector 4.

[0058] Multiple positive electrode plates 1 and multiple negative electrode plates 2 are alternately arranged. A positive electrode plate 1 includes a positive electrode body 11 and a positive electrode tab 12, with the positive electrode tab 12 connected to a first edge of the positive electrode body 11. A negative electrode plate 2 includes a negative electrode body 21 and a negative electrode tab 22, with the negative electrode tab 22 connected to a second edge of the negative electrode body 21. At least one of the positive electrode tabs 12 and negative electrode tabs 22 is arranged in multiple groups, and the number of positive electrode tabs 12 in each group and the number of negative electrode tabs 22 in each group do not exceed a specified threshold. A first connector 3 has multiple first welding points 30, each first welding point 30 being welded to a group of positive electrode tabs 12. A second connector 4 has multiple second welding points 40, each second welding point 40 being welded to a group of negative electrode tabs 22.

[0059] In this way, each first welding part 30 of the first connector 3 is welded to a group of positive tabs 12, and each second welding part 40 of the second connector 4 is welded to a group of negative tabs 22. The number of positive tabs 12 in each group and the number of negative tabs 22 in each group do not exceed the specified threshold. That is, multiple tabs are welded to the connector in groups, which reduces the number of tab layers welded to the same welding part of the connector. This allows for the welding of more tabs on the connector, the arrangement of more layers of electrode sheets inside the cell, and the improvement of the cell's output power performance.

[0060] This application does not limit the type of battery cell in its embodiments. For example, refer to... Figure 9As shown, the battery cell can be a laminated cell, where multiple positive electrode plates 1 and multiple negative electrode plates 2 are stacked alternately; another example is that the battery cell can also be a wound cell, where multiple positive electrode plates 1 and multiple negative electrode plates 2 are placed alternately and wound continuously into a cylindrical or square structure according to a certain order. Unless otherwise specified, the following embodiments will be described using a laminated cell type. The principle of a wound cell type is similar and will not be repeated here.

[0061] Among them, reference Figure 9 As shown, the battery cell also includes an insulating diaphragm 5, which is located next to the positive electrode 1 and the negative electrode 2. The insulating diaphragm 5 serves two purposes: firstly, it prevents direct contact between the positive and negative electrodes, which could lead to a short circuit inside the battery cell and ensure the safety of the battery module; secondly, the insulating diaphragm 5 also has a certain mechanical strength, which can maintain dimensional stability in high-temperature environments and prevent thermal runaway of the battery cell.

[0062] This application does not specifically limit the material of the insulating diaphragm 5. It can be matched and set according to parameters such as processing technology and manufacturing cost. For example, the insulating diaphragm 5 can be a polyolefin material (e.g., polyethylene, polypropylene, etc.) or a ceramic-coated diaphragm (substrate + ceramic particles).

[0063] This application does not specifically limit the structure of the insulating diaphragm 5. The insulating diaphragm 5 between each adjacent positive electrode 1 and negative electrode 2 can be an independent element or an integrated element bent in a Z-shape.

[0064] In some embodiments, the specified threshold value ranges from 25 to 30. If the specified threshold is less than 25, the effective connection of each layer of positive tab 12 or each layer of negative tab 22 can be guaranteed by a single welding. If the specified threshold for the number of layers in each group is too small, it will result in too many tab groups, increasing the difficulty and cost of connecting the tabs and connectors.

[0065] If the specified threshold is greater than 30, it will result in too many layers in each group of electrodes, exceeding the maximum number of layers that can be effectively welded in one ultrasonic welding, which may easily lead to some electrodes melting excessively and breaking.

[0066] This application does not specifically limit the number of groups of all positive tabs 12 in the battery cell; the number can be matched and set according to the total number of positive tabs 12. For example, refer to Figure 3 As shown, all the positive tabs 12 of the battery cell are divided into two groups; another example, referring to Figure 4 As shown, all the positive tabs 12 of the battery cell are divided into three groups.

[0067] This application does not specifically limit the number of positive tabs 12 contained in each group of positive tabs 12. For example, each group of positive tabs 12 may contain the same number of positive tabs 12. If the number of positive tabs 12 contained in the battery cell is 50, then all the positive tabs 12 in the battery cell are divided into two groups, each group containing 25 positive tabs 12.

[0068] As another example, each group of positive tabs 12 can contain a different number of positive tabs 12. If the number of positive tabs 12 contained in the battery cell is 55, then all the positive tabs 12 in the battery cell are divided into two groups, one group containing 25 positive tabs 12 and the other group containing 30 positive tabs 12.

[0069] In some embodiments, refer to Figure 2 As shown, multiple positive electrode tabs 12 are all located on the same side of multiple positive electrode bodies 11, in the stacking direction of the positive electrode tabs 12 ( Figure 2 On the corresponding direction of the Z-axis in the coordinate system, multiple positive tabs 12 are positioned opposite each other and opposite to the first connector 3, with the positive tabs 12 in the same group being adjacent to each other.

[0070] In any two sets of positive electrode tabs 12, the first set of positive electrode tabs 12 that is furthest from the first connector 3 is in the first direction ( Figure 2 The length in the corresponding direction of the X-axis (in the coordinate system) is greater than the length of the second set of positive electrode tabs 12 near the first connector 3 in the first direction, that is... Figure 3 In the first group of positive electrode tabs 12, H1 < H2, L1 < L2, and the portion of the first group of positive electrode tabs 12 protruding from the second group of positive electrode tabs 12 in the first direction is welded to the first welding portion 30, wherein the first direction is the same as the stacking direction and the first edge ( Figure 2 The direction perpendicular to the Y-axis (corresponding direction of the coordinate axis).

[0071] In this way, the multiple first welding points 30 on the first connector 3 can be distributed along the first direction, which can reduce the size of the first connector 3 in the first edge extension direction and avoid the first connector 3 occupying too much space in the first edge extension direction.

[0072] In some embodiments, each set of positive electrode tabs 12 has the same size in the direction of extension of the first edge, i.e. Figure 2 In the stacking direction of the positive tabs 12, D1 = D2, and the edges of each group of positive tabs 12 are aligned in the first edge extension direction. This further reduces the space occupied by the positive tabs 12 in the first edge extension direction of the cell, thereby improving the volumetric energy density of the cell.

[0073] At the same time, this positive tab 12 setting can also ensure that the relative positional relationship between the positive tab 12 in the same group and the corresponding positive electrode body 11 is the same, which facilitates the mass production of the positive tab 12 and the positive electrode body 11. Assembly personnel also do not need to identify the stacking relationship of the positive tabs 12 in the same group, simplifying the cell processing technology.

[0074] In some embodiments, refer to Figure 5 As shown, multiple positive electrode tabs 12 are all located on the same side of multiple positive electrode bodies 11, in the stacking direction of the positive electrode tabs 12 ( Figure 5 On the corresponding direction of the coordinate axis Z, there is an overlap between all positive tabs 12 in the same group. The first region in the overlapping region is not opposite to the positive tabs 12 of other groups, and the first region is opposite to and welded to a first welding part 30 of the first connector 3.

[0075] In this way, the multiple first welding points 30 on the first connector 3 can be distributed along the first edge extension direction, which can reduce the size of the first connector 3 in the first direction and avoid the first connector 3 occupying too much space in the first direction.

[0076] In some embodiments, refer to Figure 5 As shown, all positive tabs 12 in the same group are completely overlapping, and there is no opposition between positive tabs 12 in each group. This arrangement of positive tabs 12 ensures that the relative positional relationship between the positive tabs 12 in the same group and the corresponding positive electrode body 11 is the same, which facilitates the mass production of positive tabs 12 and positive electrode body 11. Assembly personnel also do not need to identify the stacking relationship of positive tabs 12 in the same group, simplifying the cell processing technology.

[0077] In other embodiments, reference is made to Figure 6 As shown, all positive electrode tabs 12 in the same group completely overlap, and there is partial overlap between adjacent groups of positive electrode tabs 12. This reduces the size of the positive electrode tab 12 in the first edge extension direction and avoids the positive electrode tab 12 occupying too much space in the first edge extension direction.

[0078] In some embodiments, refer to Figure 7 As shown, the first connector 3 includes a first segment 31 and a second segment 32 that are connected to each other. The first segment 31 extends along a first direction, and the second segment 32 extends along the stacking direction of the positive electrode tab 12. Figure 7 The direction corresponding to the Z-axis in the coordinate system extends, wherein the first direction is perpendicular to the stacking direction and the first edge.

[0079] Multiple positive electrode tabs 12 are located on the same side of multiple positive electrode bodies 11. Among the multiple sets of positive electrode tabs 12, at least one set of positive electrode tabs 12 is opposite to and welded to the first welding part 30 located in the first section 31, and the other sets of positive electrode tabs 12 are opposite to and welded to the first welding part 30 located in the second section 32.

[0080] by Figure 7 Taking the positive tab 12 shown as an example, all the positive tabs 12 of the battery cell are divided into two groups. One group of positive tabs 12 is opposite to and welded to the first welding part 30 located in the first section 31, and the other group of positive tabs 12 is opposite to and welded to the first welding part 30 located in the second section 32.

[0081] In this way, the size of the positive electrode tab 12 welded to the first welding part 30 located in the second segment 32 in the first direction can be shortened, thus avoiding the positive electrode tab 12 occupying too much space in the first direction.

[0082] In some embodiments, the positive tabs 12 in the same group are of the same size. Setting the positive tabs 12 of the same size facilitates the mass production of the positive tabs 12, reduces the manufacturing cost of the positive tabs 12 and the battery cell, and simplifies the battery cell processing technology as assembly personnel do not need to identify the stacking relationship of the positive tabs 12 in the same group.

[0083] It should be noted that the dimension of each positive electrode tab 12 in a certain direction refers to the smallest dimension of the multiple positive electrode tabs 12 in a certain direction within each group.

[0084] In some embodiments, refer to Figure 1 As shown, the first connector 3 includes a first layer 3a and a second layer 3b welded together. The first layer 3a is opposite to the positive electrode tab 12 and is used for welding to the positive electrode tab 12. The stiffness of the first layer 3a is greater than that of the positive electrode tab 12. The second layer 3b is located on the side of the first layer 3a away from the positive electrode tab 12 and is used for connecting to electronic components outside the battery cell. The stiffness of the second layer 3b is greater than that of the first layer 3a.

[0085] On the one hand, temperature changes during charging and discharging of the battery cell will cause the positive electrode tab 12 material to expand or contract. Since the stiffness difference between the positive electrode tab 12 and the second layer 3b is large, direct connection may generate mechanical stress due to deformation difference, which is prone to breakage after long-term use. The first layer 3a, whose stiffness is between the second layer 3b and the positive electrode tab 12, can effectively absorb stress and avoid fatigue at the connection position between the positive electrode tab 12 and the first connector 3.

[0086] On the other hand, the first layer 3a and the second layer 3b can be made of the same material and connected by laser welding. The first layer 3a and the positive electrode tab 12 are connected by ultrasonic welding. Since the laser welding position of the first layer 3a and the second layer 3b has a large strength, the setting of the first layer 3a can enhance the structural strength of the first connector 3.

[0087] Meanwhile, the first layer 3a can also be designed as a fusible structure, meaning that when the target temperature is exceeded, the first layer 3a will melt first to prevent the thermal runaway of the battery cell from spreading continuously.

[0088] In some embodiments, refer to Figure 2As shown, multiple negative electrode tabs 22 are all located on the same side of multiple negative electrode bodies 21, in the stacking direction of the negative electrode tabs 22 ( Figure 2 On the corresponding direction of the Z-axis in the coordinate system, multiple negative tabs 22 are positioned opposite each other and opposite to the first connector 3, with the negative tabs 22 in the same group being adjacent to each other.

[0089] In any two sets of negative electrode tabs 22, the length of the first set of negative electrode tabs 22 farther from the second connector 4 in the second direction is greater than the length of the second set of negative electrode tabs 22 closer to the second connector 4 in the second direction, and the portion of the first set of negative electrode tabs 22 that protrudes from the second set of negative electrode tabs 22 in the second direction is welded to the second welding portion 40, wherein the second direction is the direction perpendicular to the stacking direction and the second edge.

[0090] In this way, the multiple second welding points 40 on the second connector 4 can be distributed along the second direction, which can reduce the size of the second connector 4 in the second edge extension direction and avoid the second connector 4 occupying too much space in the second edge extension direction.

[0091] In some embodiments, each set of negative electrode tabs 22 has the same size in the direction of extension of the second edge, i.e. Figure 2 In the stacking direction of the negative electrode tabs 22, D3 = D4, and the edges of each group of negative electrode tabs 22 are aligned in the second edge extension direction. This further reduces the space occupied by the negative electrode tabs 22 in the second edge extension direction of the cell, thereby improving the volumetric energy density of the cell.

[0092] At the same time, this negative electrode tab 22 setting can also ensure that the relative positional relationship between the negative electrode tab 22 in the same group and the corresponding negative electrode body 21 is the same, which facilitates the mass production of the negative electrode tab 22 and the negative electrode body 21. Assembly personnel also do not need to identify the stacking relationship of the negative electrode tabs 22 in the same group, simplifying the processing technology of the battery cell.

[0093] In some embodiments, refer to Figure 5 As shown, multiple negative electrode tabs 22 are all located on the same side of multiple negative electrode bodies 21, in the stacking direction of the negative electrode tabs 22 ( Figure 5 On the corresponding direction of the coordinate axis Z, there is an overlap between all negative electrode tabs 22 in the same group. The second region in the overlapping area is not opposite to the negative electrode tabs 22 of other groups, and the second region is opposite to and welded to a second welding part 40 of the second connector 4.

[0094] In this way, the multiple second welding points 40 on the second connector 4 can be distributed along the second edge extension direction, which can reduce the size of the second connector 4 in the second direction and avoid the second connector 4 occupying too much space in the second direction.

[0095] In some embodiments, refer to Figure 5As shown, all negative tabs 22 in the same group are completely overlapping, and there is no opposition between negative tabs 22 in each group. This arrangement of negative tabs 22 ensures that the relative positional relationship between the negative tabs 22 in the same group and the corresponding negative electrode body 21 is the same, which facilitates the mass production of negative tabs 22 and negative electrode body 21. Assembly personnel also do not need to identify the stacking relationship of negative tabs 22 in the same group, simplifying the cell processing technology.

[0096] In other embodiments, reference is made to Figure 6 As shown, all negative electrode tabs 22 in the same group completely overlap, and there is partial overlap between adjacent groups of negative electrode tabs 22. This reduces the size of the negative electrode tabs 22 in the direction of the second edge extension, preventing the negative electrode tabs 22 from occupying too much space in the direction of the second edge extension.

[0097] In some embodiments, the second connector 4 includes a third segment 41 and a fourth segment 42 connected to each other, the third segment 41 extending along a second direction and the fourth segment 42 extending along the stacking direction of the negative electrode tab 22, wherein the second direction is a direction perpendicular to the stacking direction and the second edge.

[0098] Multiple negative electrode tabs 22 are located on the same side of multiple negative electrode sheet bodies 21. Among the multiple sets of negative electrode tabs 22, at least one set of negative electrode tabs 22 is opposite to and welded to the second welding part 40 located in the third section 41, and the remaining sets of negative electrode tabs 22 are opposite to and welded to the second welding part 40 located in the fourth section 42.

[0099] by Figure 8 Taking the negative electrode tab 22 shown as an example, all the negative electrode tabs 22 of the battery cell are divided into two groups. One group of negative electrode tabs 22 is opposite to and welded to the second welding part 40 located in the third section 41, and the other group of negative electrode tabs 22 is opposite to and welded to the second welding part 40 located in the fourth section 42.

[0100] In this way, the size of the negative electrode tab 22, which is welded to the second welding part 40 located in the fourth segment 42, in the second direction can be shortened, thus avoiding the negative electrode tab 22 occupying too much space in the second direction.

[0101] In some embodiments, the negative tabs 22 in the same group are of the same size. Setting negative tabs 22 of the same size facilitates the mass production of negative tabs 22, reduces the manufacturing cost of negative tabs 22 and battery cells, and eliminates the need for assembly personnel to identify the stacking relationship of negative tabs 22 in the same group, thus simplifying the battery cell processing technology.

[0102] It should be noted that the dimension of each negative electrode tab 22 in a certain direction refers to the smallest dimension of the multiple negative electrode tabs 22 in a certain direction within each group.

[0103] In some embodiments, refer to Figure 1As shown, the second connector 4 includes a third layer 4a and a fourth layer 4b welded together. The third layer 4a is opposite to the negative electrode tab 22 and is used for welding to the negative electrode tab 22. The stiffness of the third layer 4a is greater than that of the negative electrode tab 22. The fourth layer 4b is located on the side of the third layer 4a away from the negative electrode tab 22 and is used for connecting to electronic components outside the battery cell. The stiffness of the fourth layer 4b is greater than that of the third layer 4a.

[0104] On the one hand, temperature changes during battery cell charging and discharging will cause the material of negative electrode tab 22 to expand or contract. Due to the large difference in stiffness between negative electrode tab 22 and fourth layer 4b, direct connection may generate mechanical stress due to deformation differences, which may lead to breakage after long-term use. The setting of third layer 4a with stiffness between fourth layer 4b and negative electrode tab 22 can effectively absorb stress and avoid fatigue at the connection position between negative electrode tab 22 and second connector 4.

[0105] On the other hand, the third layer 4a and the fourth layer 4b can be made of the same material and connected by laser welding. The third layer 4a and the negative electrode tab 22 are connected by ultrasonic welding. Since the laser welding position of the third layer 4a and the fourth layer 4b has greater strength, the setting of the third layer 4a can enhance the structural strength of the second connector 4.

[0106] Meanwhile, the third layer 4a can also be designed as a fusible structure, meaning that when the target temperature is exceeded, the third layer 4a will melt first, preventing the thermal runaway of the battery cell from spreading continuously.

[0107] Based on the same concept, this application provides a battery module including the battery cell in any of the above embodiments. Each first welding part 30 of the first connector 3 is welded to a group of positive tabs 12, and each second welding part 40 of the second connector 4 is welded to a group of negative tabs 22. The number of positive tabs 12 in each group and the number of negative tabs 22 in each group do not exceed a specified threshold. That is, multiple tabs are welded to the connector in groups, which reduces the number of tab layers welded to the same welding part of the connector. This allows for the welding of more tabs on the connector, and more layers of electrode sheets to be arranged inside the battery cell, thereby improving the output power performance of the battery cell.

[0108] In the description of this specification, the references to "certain embodiments," "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples" refer to specific features, structures, materials, or characteristics described in connection with the described embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. Furthermore, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0109] It is understood that in this application, "multiple" refers to two or more, and other quantifiers are similar. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. The singular forms "a," "the," and "the" are also intended to include the plural forms unless the context clearly indicates otherwise.

[0110] It is further understood that the terms "first," "second," etc., are used to describe various types of information, but this information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another, and do not indicate a specific order or degree of importance. In fact, the expressions "first," "second," etc., are completely interchangeable. For example, without departing from the scope of this application, first information can also be referred to as second information, and similarly, second information can also be referred to as first information.

[0111] It is further understood that the terms “center,” “longitudinal,” “lateral,” “front,” “rear,” “up,” “down,” “left,” “right,” “vertical,” “horizontal,” “top,” “bottom,” “inner,” “outer,” “clockwise,” “counterclockwise,” “axial,” “radial,” and “circumferential” indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this embodiment and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation.

[0112] It is further understood that, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral molding; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between the two components; they can refer to a direct connection between two components without the presence of other components, or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0113] It is further understood that although the operations are described in a specific order in the accompanying drawings in the embodiments of this application, this should not be construed as requiring these operations to be performed in the specific order or serial order shown, or requiring all the operations shown to obtain the desired result. In certain environments, multitasking and parallel processing may be advantageous.

[0114] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the solutions disclosed herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein. The specification and embodiments are to be considered exemplary only, and the true scope and spirit of this application are indicated by the scope of claims.

[0115] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this application is limited only by the appended claims.

Claims

1. A battery cell, characterized in that, The battery cell includes multiple positive electrode plates (1), multiple negative electrode plates (2), a first connector (3), and a second connector (4); Multiple positive electrode plates (1) and multiple negative electrode plates (2) are arranged alternately; The positive electrode (1) includes a positive electrode body (11) and a positive electrode tab (12), the positive electrode tab (12) being connected to the first edge of the positive electrode body (11). The negative electrode (2) includes a negative electrode body (21) and a negative electrode tab (22), the negative electrode tab (22) being connected to the second edge of the negative electrode body (21). At least one of the positive electrode tab (12) and the negative electrode tab (22) is set to multiple groups, and the number of each group of positive electrode tabs (12) and each group of negative electrode tabs (22) does not exceed a specified threshold. The first connector (3) has multiple first welding points (30), each of which is welded to a set of positive tabs (12). The second connector (4) has multiple second welding points (40), each of which is welded to a set of negative tabs (22).

2. The battery cell according to claim 1, characterized in that, The multiple positive tabs (12) are located on the same side of the multiple positive electrode bodies (11). In the stacking direction of the positive tabs (12), the multiple positive tabs (12) are opposite to each other and opposite to the first connector (3). The positive tabs (12) in the same group are adjacent to each other. In any two sets of positive tabs (12), the first set of positive tabs (12) farther from the first connector (3) has a longer length in the first direction than the second set of positive tabs (12) closer to the first connector (3) in the first direction, and the portion of the first set of positive tabs (12) protruding from the second set of positive tabs (12) in the first direction is welded to the first welding portion (30), wherein the first direction is a direction perpendicular to the stacking direction and the first edge.

3. The battery cell according to claim 1, characterized in that, The multiple positive tabs (12) are located on the same side of the multiple positive electrode bodies (11). In the stacking direction of the positive tabs (12), there is an overlap between all the positive tabs (12) in the same group. The first region in the overlapping region is not opposite to the positive tabs (12) of other groups, and the first region is opposite to and welded to a first welding part (30) of the first connector (3).

4. The battery cell according to claim 1, characterized in that, The first connector (3) includes a first segment (31) and a second segment (32) that are connected to each other. The first segment (31) extends along a first direction, and the second segment (32) extends along the stacking direction of the positive electrode tab (12). The first direction is a direction that is perpendicular to the stacking direction and the first edge. The multiple positive tabs (12) are located on the same side of the multiple positive electrode bodies (11). Among the multiple sets of positive tabs (12), at least one set of positive tabs (12) is opposite to and welded to the first welding part (30) located in the first segment (31), and the remaining sets of positive tabs (12) are opposite to and welded to the first welding part (30) located in the second segment (32).

5. The battery cell according to any one of claims 1 to 4, characterized in that, The positive electrode tabs (12) in the same group are the same size.

6. The battery cell according to any one of claims 1 to 4, characterized in that, The first connector (3) comprises a first layer (3a) and a second layer (3b) welded together; The first layer (3a) is opposite to the positive electrode tab (12) and is used for welding to the positive electrode tab (12). The stiffness of the first layer (3a) is greater than the stiffness of the positive electrode tab (12). The second layer (3b) is located on the side of the first layer (3a) away from the positive electrode tab (12) and is used to connect to electronic components outside the battery cell. The stiffness of the second layer (3b) is greater than that of the first layer (3a).

7. The battery cell according to claim 1, characterized in that, The multiple negative electrode tabs (22) are located on the same side of the multiple negative electrode sheet bodies (21). In the stacking direction of the negative electrode tabs (22), the multiple negative electrode tabs (22) are opposite to each other and opposite to the first connector (3). The negative electrode tabs (22) in the same group are adjacent to each other. In any two sets of negative tabs (22), the length of the first set of negative tabs (22) away from the second connector (4) in the second direction is greater than the length of the second set of negative tabs (22) closer to the second connector (4) in the second direction, and the portion of the first set of negative tabs (22) protruding from the second set of negative tabs (22) in the second direction is welded to the second welding portion (40), wherein the second direction is a direction perpendicular to the stacking direction and the second edge.

8. The battery cell according to claim 1, characterized in that, The multiple negative tabs (22) are located on the same side of the multiple negative electrode bodies (21). In the stacking direction of the negative tabs (22), there is an overlap between all the negative tabs (22) in the same group. The second region in the overlapping area is not opposite to the negative tabs (22) of other groups, and the second region is opposite to and welded to a second welding part (40) of the second connector (4).

9. The battery cell according to claim 1, characterized in that, The second connector (4) includes a third segment (41) and a fourth segment (42) that are connected to each other. The third segment (41) extends along a second direction, and the fourth segment (42) extends along the stacking direction of the negative electrode tab (22). The second direction is a direction perpendicular to the stacking direction and the second edge. The multiple negative electrode tabs (22) are located on the same side of the multiple negative electrode sheet bodies (21). Among the multiple sets of negative electrode tabs (22), at least one set of negative electrode tabs (22) is opposite to and welded to the second welding part (40) located in the third segment (41), and the remaining sets of negative electrode tabs (22) are opposite to and welded to the second welding part (40) located in the fourth segment (42).

10. The battery cell according to any one of claims 1, 7, 8 or 9, characterized in that, The negative electrode tabs (22) in the same group are the same size.

11. The battery cell according to any one of claims 1, 7, 8 or 9, characterized in that, The second connector (4) includes a third layer (4a) and a fourth layer (4b) welded together; The third layer (4a) is opposite to the negative electrode tab (22) and is used for welding to the negative electrode tab (22). The stiffness of the third layer (4a) is greater than that of the negative electrode tab (22). The fourth layer (4b) is located on the side of the third layer (4a) away from the negative electrode tab (22) and is used to connect to electronic components outside the battery cell. The stiffness of the fourth layer (4b) is greater than that of the third layer (4a).

12. The battery cell according to claim 1, characterized in that, The specified threshold value ranges from 25 to 30.

13. A battery module, characterized in that, The battery module includes the battery cells as described in any one of claims 1-12.

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