Single cell and battery pack

Abstract

The present disclosure relates to the technical field of batteries, and discloses a single battery and a battery pack; the single battery comprises a pole member, a battery cell and at least two groups of welding connection groups; the battery cell comprises a battery cell main body and a tab, and the tab is connected to the battery cell main body; each welding connection group comprises at least two welding connection structures, and the welding connection structures are connected between the pole member and the tab; the minimum distance between two adjacent welding connection groups is a, the minimum distance between the farthest two welding connection structures in the same welding connection group is d, and the value of a×d is greater than or equal to 4 mm 2 less than or equal to 68 mm 2 The single battery guarantees the overcurrent capacity between the welding connection structure and the tab, reduces the heat generation, and avoids thermal runaway due to serious heat generation during charging and discharging.

Description

Technical Field

[0001] This disclosure relates to the field of battery technology, and more specifically, to a single cell battery and a battery pack including the single cell battery. Background Technology

[0002] Welding is a common process in the manufacturing of single-cell batteries. The terminal components of a single-cell battery are connected to the tabs through welding. However, there are currently no restrictions on the welding between the terminal components and the tabs, resulting in poor current carrying capacity after welding and easy overheating. Especially during charging and discharging, severe overheating can easily lead to thermal runaway.

[0003] It should be noted that the information disclosed in the background section above is only used to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art. Utility Model Content

[0004] The purpose of this disclosure is to overcome the shortcomings of the above-mentioned related technologies and to provide a single cell battery and a battery pack including the single cell battery.

[0005] According to one aspect of this disclosure, a single-cell battery is provided, comprising:

[0006] pole post components;

[0007] A battery cell includes a cell body and tabs, wherein the tabs are connected to the cell body;

[0008] At least two sets of welded connection groups, each set comprising at least two welded connection structures, are connected between the pole member and the pole lug. The minimum distance between two adjacent sets of welded connection groups is 'a', and within the same set, the minimum distance between the two furthest welded connection structures is 'd', where a × d is greater than or equal to 4 mm. 2 Less than or equal to 68mm 2 .

[0009] The single-cell battery disclosed herein, on the one hand, provides at least two sets of welding connection groups to avoid the defect of insufficient current distribution at each welding connection structure when welding a large number of welding connection structures simultaneously, thus preventing the formation of large weld marks; that is, it enables a larger weld mark area at the connection between the welding connection structure and the electrode tab, thereby improving the overcurrent capacity between the electrode post component and the electrode tab, reducing heat generation, and preventing thermal runaway due to severe heat generation during charging and discharging. On the other hand, the value of a×d is greater than or equal to 4mm. 2 Less than or equal to 68mm 2This not only avoids the impact of subsequent resistance welding processes on the already formed weld marks due to overcurrent melting, ensuring that weld marks are easily formed between the welded connection structure and the electrode tab to guarantee the overcurrent capacity between the welded connection structure and the electrode tab; it also ensures that a sufficient number of welded connection groups can be set up, ensuring that the height difference between each welded connection structure is small, the pressure difference between the welded connection structures is small during resistance welding, and the area of ​​each weld mark is relatively uniform, avoiding melting at some welded connection structures; and it also avoids the adhesion between two adjacent welded connection structures.

[0010] According to another aspect of this disclosure, a battery pack is provided, comprising:

[0011] Battery box;

[0012] The single cell is the single cell described above, and the single cell is disposed inside the battery box.

[0013] The battery pack disclosed herein, on the one hand, features at least two sets of welding connection groups. This avoids the problem of insufficient current distribution at each welding connection structure, resulting in inadequate weld formation, when welding a large number of welding connection structures simultaneously. In other words, it allows for a larger weld area connecting the welding connection structure to the electrode tab, thereby improving the current-carrying capacity between the electrode post and the electrode tab, reducing heat generation, and preventing thermal runaway due to severe overheating during charging and discharging, thus enhancing the safety of the battery pack. On the other hand, the value of a×d is greater than or equal to 4mm. 2 Less than or equal to 68mm 2 This not only avoids the impact of subsequent resistance welding processes on the already formed weld marks due to overcurrent melting, ensuring that the welded connection structure currently undergoing resistance welding can easily form weld marks between the welded connection structure and the electrode, thus guaranteeing the overcurrent capacity between the welded connection structure and the electrode; it also ensures that a sufficient number of welded connection groups can be set up, ensuring that the height difference between each welded connection structure is small, the pressure difference between the welded connection structures is small during resistance welding, and the area of ​​each weld mark is relatively uniform, avoiding melting at some welded connection structures; and it also avoids the easy adhesion between two adjacent welded connection structures, thus ensuring the electrical performance of the battery pack.

[0014] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this disclosure. Attached Figure Description

[0015] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure. It is obvious that the drawings described below are merely some embodiments of this disclosure, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0016] Figure 1 This is a three-dimensional structural diagram of an example embodiment of a single-cell battery disclosed herein.

[0017] Figure 2 for Figure 1 A partial cross-sectional view of a single cell.

[0018] Figure 3 for Figure 2 A three-dimensional structural diagram of the intermediate transfer joint.

[0019] Figure 4 for Figure 3 A top view of the intermediate connection section.

[0020] Figure 5 This is a schematic diagram of another example embodiment of the terminal assembly in the battery disclosed herein.

[0021] Figure 6 This is a schematic diagram of the structure of the electrode assembly in the battery disclosed herein, showing its engagement with the tab.

[0022] Explanation of reference numerals in the attached figures:

[0023] 1. Battery casing; 11. First casing; 12. Second casing;

[0024] 2. Terminal post component; 21. Adapter part; 211. Adapter plate; 212. Adapter post; 22. Battery terminal post;

[0025] 3. Battery cell; 31. Battery cell body; 32. Electrode; 32a. First electrode; 32b. Second electrode;

[0026] 4. Welded connection assembly; 41. Welded connection structure;

[0027] X, the first direction; Y, the second direction. Detailed Implementation

[0028] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein; rather, they are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the exemplary embodiments to those skilled in the art. The same reference numerals in the drawings denote the same or similar structures, and therefore detailed descriptions of them will be omitted. Furthermore, the drawings are merely illustrative of this disclosure and are not necessarily drawn to scale.

[0029] Although relative terms such as "up" and "down" are used in this specification to describe the relative relationship of one component of an icon to another, these terms are used only for convenience, such as according to the orientation of the examples shown in the accompanying drawings. It is understood that if the device of the icon is flipped upside down, the component described as "up" will become the component described as "down." When a structure is "up" of another structure, it may mean that the structure is integrally formed on the other structure, or that the structure is "directly" mounted on the other structure, or that the structure is "indirectly" mounted on the other structure through another structure.

[0030] The terms “a,” “one,” “the,” “the,” and “at least one” are used to indicate the presence of one or more elements / components / etc.; the terms “including” and “having” are used to indicate an open-ended inclusion and to mean that there may be other elements / components / etc. in addition to the listed elements / components / etc.; the terms “first,” “second,” and “third,” etc., are used only as markers and are not a limitation on the number of objects.

[0031] In this application, unless otherwise expressly specified and limited, the term "connection" should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral part; it can be a direct connection or an indirect connection through an intermediate medium. "And / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Furthermore, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0032] A battery cell is the component in a battery where electrochemical reactions occur; it is the smallest unit in a battery capable of performing electrochemical reactions such as charging and discharging. A battery cell is the basic unit of a battery and typically includes a positive electrode, a negative electrode, and a separator. Lithium-ion battery cells primarily function by the movement of lithium ions between the positive and negative electrodes. In cylindrical cells, a three-layer thin-film structure is wound into a cylindrical electrode assembly, while in cuboid cells, the thin-film structure is wound or stacked into an electrode assembly with a roughly cuboid shape.

[0033] A positive electrode generally includes a positive current collector and a positive active material layer. The positive active material layer is coated on at least one surface of the positive current collector and includes: a positive active material, a conductive agent, and a binder. A negative electrode includes a negative current collector and a negative active layer disposed on at least one surface of the negative current collector. The negative current collector is a conductive metal foil, which can be made of stainless steel, copper, aluminum, nickel, carbon electrodes, or titanium, etc., with a silver-plated surface. Composite current collectors may include a polymer base layer and a metal layer. A tab is disposed on one side of the positive / negative current collector and is separately / integrated with the current collector, electrically connected to the current collector to conduct current from the corresponding current collector. It is made of a metal material with good conductivity (such as copper, aluminum, or nickel).

[0034] The terminal post is used to electrically connect the electrode assembly located inside the housing to external devices (adjacent batteries or other electrical equipment) located outside the housing. The battery can discharge to external devices through the cell output terminal (tab) and the external device output terminal (terminal post), and an external power source can charge the battery through the terminal post assembly and the tab. The terminal post can be directly electrically connected to the cell tab or electrically connected to the tab through a metal adapter. The terminal post is made of metals including, but not limited to, copper, aluminum, aluminum alloy, and copper-aluminum alloy.

[0035] This disclosure provides an example embodiment of a single-cell battery, with reference to... Figures 1-6 As shown, the single battery cell may include a terminal post 2, a cell 3, and at least two sets of welded connection groups 4; the cell 3 may include a cell body 31 and a tab 32, with the tab 32 connected to the cell body 31; the welded connection group 4 may include at least two welded connection structures 41, which are connected between the terminal post 2 and the tab 32. The minimum distance between two adjacent sets of welded connection groups 4 is 'a', and the minimum distance between the two furthest welded connection structures 41 within the same welded connection group 4 is 'd', where the value of a × d is greater than or equal to 4 mm. 2 Less than or equal to 68mm 2 .

[0036] The single-cell battery disclosed herein, on the one hand, provides at least two sets of welding connection groups 4 to avoid the defect of insufficient current distribution at each welding connection structure 41 due to simultaneous welding of a large number of welding connection structures 41, thus preventing the formation of large weld marks; that is, it enables a larger weld mark area at the connection between the welding connection structure 41 and the electrode tab 32, thereby improving the overcurrent capacity between the electrode post member 2 and the electrode tab 32, reducing heat generation, and preventing thermal runaway due to severe heat generation during charging and discharging. On the other hand, the value of a×d is greater than or equal to 4mm. 2 Less than or equal to 68mm 2This not only avoids the subsequent resistance welding process from causing the already formed weld to melt due to overcurrent, ensuring that the welded connection structure 41 and the tab 32 currently being resisted welded can easily form a weld, thus ensuring the overcurrent capacity between the welded connection structure 41 and the tab 32; but also ensures that a sufficient number of welded connection groups 4 can be set up, ensuring that the height difference between each welded connection structure 41 is small, the pressure difference between the welded connection structures 41 is small during the resistance welding process, and the area of ​​each weld is relatively uniform, avoiding melting at some welded connection structures 41; and also avoids the adhesion between two adjacent welded connection structures 41.

[0037] In some exemplary embodiments of this disclosure, reference is made to Figure 1 As shown, the battery can be configured as a generally cuboid structure, therefore, the battery casing 1 can also be configured as a generally cuboid structure. Specifically, the battery casing 1 may include a first casing 11 and a second casing 12. The first casing 11 can be configured as a generally cuboid structure, and the second casing 12 can be configured as a rectangular plate. The first casing 11 has a cavity, and an opening communicating with the cavity is provided on one side of the first casing 11, which can be formed by removing one of the largest faces of the first casing 11. The first casing 11 has a flange around its opening, and the second casing 12 is connected to the flange and closes the opening of the first casing 11. Accordingly, the first casing 11 and the second casing 12 together form a receiving space for accommodating the battery cell 3. The first casing 11 can be a one-piece molded structure.

[0038] Two recessed structures are provided on the side of the first housing 11 away from the second housing 12, and the two recessed structures are located at both ends of the first housing 11 in the length direction.

[0039] Of course, in other exemplary embodiments of this disclosure, the battery casing 1 may include a cover plate, a bottom plate, and four side plates; the four side plates are arranged opposite each other in pairs; the four side plates are connected end to end in sequence to form a rectangular cylindrical shape. A cover plate is connected to one side of each of the four side plates, and a bottom plate is connected to the opposite side of each of the four side plates. The bottom plate and the cover plate may be rectangular, and the cover plate, the bottom plate, and the four side plates surround to form an accommodating space; moreover, the cover plate, the bottom plate, and the four side plates may be an integrally formed structure, which can reduce the welds of the battery casing 1 to improve the sealing performance of the battery casing 1; or they may be separately formed and then connected into one piece by welding or other methods.

[0040] Of course, in other exemplary embodiments of this disclosure, the base plate and cover plate may be configured as circular, elliptical, trapezoidal, etc., and the side plates may be configured as one or more, and formed in a circular, elliptical, trapezoidal, etc., so that the battery casing 1 is formed as cylindrical, elliptical cylindrical, prismatic, etc.

[0041] The battery casing 1 can be made of aluminum, steel or other metals, alloys, etc. Of course, it can also be made of other materials, which will not be listed here.

[0042] Reference Figure 2 As shown, a battery cell 3 is disposed inside the battery casing 1. The battery cell 3 may include a battery cell body 31 and a tab 32.

[0043] In some exemplary embodiments of this disclosure, the cell body 31 may be configured as a stacked structure. To fit into the rectangular battery casing 1, the cell body 31 is also configured as a rectangular structure. The cell body 31 may include a first electrode, a separator, and a second electrode stacked sequentially, and the first electrode, the separator, and the second electrode are all configured as multiple layers.

[0044] Of course, in some other exemplary embodiments of this disclosure, the cell body 31 can be a wound type, which is formed by winding the stacked structure of the first electrode, the separator and the second electrode.

[0045] The first electrode is the negative electrode, and the second electrode is the positive electrode. The first electrode is made of copper, for example, copper or a copper alloy. The second electrode is made of aluminum, for example, aluminum or an aluminum alloy. The first and second electrodes are coated with different active materials.

[0046] The battery cell body 31 has a first end face and a second end face that are disposed opposite to each other along its length. A first tab 32a and a second tab 32b can be disposed on opposite end faces along the length of the battery cell body 31. For example, the first tab 32a is disposed on the first end face and the second tab 32b is disposed on the second end face. Both the first tab 32a and the second tab 32b are tabs 32.

[0047] Specifically, the first tab 32a is connected to the first electrode plate, making the first tab 32a a negative tab 32; it can be a part of the first electrode plate extending out of the first end face of the cell body 31 and stacked together to form the first tab 32a, and the first tab 32a can extend continuously along the length direction of the cell body 31; moreover, the material of the first tab 32a is the same as the material of the first electrode plate, for example, both are copper, copper alloy, etc.

[0048] The second tab 32b is connected to the second electrode plate, making the second tab 32b a positive tab 32; it can be a part of the second electrode plate extending out of the second end face of the cell body 31 and stacked together to form the second tab 32b, and the second tab 32b can extend continuously along the length direction of the cell body 31; moreover, the material of the second tab 32b is the same as that of the second electrode plate, for example, both are aluminum, aluminum alloy, etc.

[0049] Of course, in some other exemplary embodiments of this disclosure, the first tab 32a can be bent to the side of the first end face away from the cell body 31. In this case, the first tab 32a can cover a portion of the first end face or the entire first end face; the second tab 32b can be bent to the side of the second end face away from the cell body 31. In this case, the second tab 32b can cover a portion of the first end face or the entire second end face. The first tab 32a and the second tab 32b can also be bent to the same side of the cell body 31.

[0050] It should be noted that the first tab 32a and the second tab 32b are conductive foil areas without active material coating, that is, no active material coating is applied to the first tab 32a and the second tab 32b. The first tab 32a and the second tab 32b are current collector layers used for transmitting current.

[0051] For the laminated battery cell body 31, the number of layers of the first electrode is generally equal to the number of layers of the first tab 32a, so that all the first electrodes can be electrically connected through the first tab 32a; similarly, the number of layers of the second electrode is generally equal to the number of layers of the second tab 32b, so that all the second electrodes can be electrically connected through the second tab 32b. Therefore, the first tab 32a may include multiple tab layers, and the second tab 32b may include multiple tab layers.

[0052] For the wound cell body 31, the number of layers of the first tab 32a can be less than or equal to the number of winding layers of the first electrode, and the number of layers of the second tab 32b can also be less than or equal to the number of winding layers of the second electrode.

[0053] In some exemplary embodiments of this disclosure, reference is made to Figure 2 As shown, a through hole is provided on the second housing 12. The pole member 2 passes through the through hole on the second housing 12, so that one end of the pole member 2 can extend into the battery housing 1, and a welding connection structure 41 is provided between the pole member 2 and the tab 32, that is, the fixed connection between the pole member 2 and the tab 32 is achieved by the welding connection structure 41.

[0054] In this example implementation, refer to Figure 2 , Figure 3 and Figure 4As shown, the terminal component 2 may include an adapter portion 21 and a battery terminal 22. The adapter portion 21 may include an adapter plate 211 and an adapter post 212. The adapter post 212 is connected to the adapter plate 211. The adapter plate 211 may be rectangular, and the adapter post 212 may be cylindrical. The adapter plate 211 is located inside the battery housing 1. The adapter post 212 passes through a through hole in the second housing 12, and one end of the adapter post 212 extends outside the battery housing 1. The battery terminal 22 may be L-shaped. The battery terminal 22 has a through hole, and the adapter post 212 passes through the through hole in the battery terminal 22 and is riveted to the battery terminal 22. The battery terminal 22 is located on the side of the second housing 12 opposite to the first housing 11, so that the battery terminal 22 protrudes from the second housing 12. In the case of multiple batteries, the battery terminal 22 may be accommodated in a recessed structure on the first housing 11 of an adjacent battery.

[0055] The adapter 21 increases the connection area between the pole member 2 and the pole lug 32 to ensure the connection between the pole member 2 and the pole lug 32 is firm.

[0056] Of course, the structure of the terminal component 2 is not limited to the above description. For example, the terminal component 2 may only include the battery terminal 22, one end of which extends through the through hole on the second housing 12 into the battery housing 1 and is connected to the tab 32 by the welding connection structure 41; the adapter part 21 may only include the adapter plate 211, one end of which extends through the through hole on the second housing 12 into the battery housing 1 and is fixedly connected to the adapter plate 211.

[0057] The welded connection structure 41 can be directly connected to the pole member 2. Specifically, the welded connection structure 41 and the pole member 2 can be integrally formed. For example, the welded connection structure 41 can be formed by stamping the transition portion 21 of the pole member 2. Of course, the welded connection structure 41 can also be formed on the transition portion 21 by machining, making the welded connection structure 41 a protruding structure provided on the transition portion 21. Generally, the accuracy of the welded connection structure 41 located in the middle position can be guaranteed, but the accuracy of the welded connection structure 41 located at the edge position is poor, especially for the stamping process.

[0058] The welding connection structure 41 is welded to the tab 32 so that the welding connection structure 41 and the tab 32 are connected with a weld mark; that is, the welding connection structure 41 and the tab 32 can be connected by welding. Specifically, the welding connection structure 41 and the tab 32 can be connected as one piece by resistance welding. After resistance welding, the welding connection structure 41 and the tab 32 are connected to form a weld mark.

[0059] Resistance welding is a welding method that uses the resistance heat generated when an electric current passes through the workpieces as a heat source to heat the workpieces, causing them to melt locally and form a weld point or weld seam. When current passes through two contacting workpieces, heat is generated at the contact point due to the resistance of the workpieces. This heat melts the metal at the contact point, forming a weld nugget. Under pressure, the weld nugget gradually increases in size and solidifies, eventually forming a strong weld mark.

[0060] During welding, the adapter 21 of the pole member 2 can be placed on the welding base, the electrode tab 32 is placed on the adapter 21, and the welding head is fixed on the electrode tab 32. The number of welding heads is consistent with the number of weld marks to be formed, or the number of welding connection structures 41 is consistent with the number of welding heads. The position of the welding heads is consistent with the position of the weld marks to be formed, or the position of the welding heads is consistent with the position of the welding connection structures 41. The welding base and welding heads are connected to the welding power source, so that the current flows through the welding base, the multiple welding connection structures 41 between the adapter 21 and the electrode tab 32, and the welding head, to achieve resistance welding between the adapter 21 and the electrode tab 32.

[0061] Of course, in other exemplary embodiments of this disclosure, the welded connection structure 41 and the tab 32 can also be connected by other welding methods, which will not be described in detail here.

[0062] In this example implementation, refer to Figure 2 , Figure 3 and Figure 4 As shown, at least two sets of welded connection groups 4 are provided. For example, two sets of welded connection groups 4 can be provided, or three or more sets of welded connection groups 4 can be provided. A set of welded connection groups 4 may include at least two welded connection structures 41. For example, a set of welded connection groups 4 may include two welded connection structures 41, or a set of welded connection groups 4 may include three or more welded connection structures 41.

[0063] One set of welded connection groups 4 is formed by a single resistance welding process, two sets of welded connection groups 4 are formed by two resistance welding processes, and so on, with at least two sets of welded connection groups 4 formed by at least two resistance welding processes. This arrangement avoids the defect of insufficient current distribution at each welded connection structure 41 when welding a large number of welded connection structures 41 simultaneously, resulting in a small weld mark. In other words, setting at least two sets of welded connection groups 4 allows for a larger weld mark area connecting the welded connection structure 41 to the electrode tab 32, thereby improving the current carrying capacity between the electrode post component 2 and the electrode tab 32, reducing heat generation, and preventing thermal runaway due to severe heat generation during charging and discharging.

[0064] However, in order to avoid the subsequent resistance welding process from affecting the already formed weld marks, the minimum spacing between two adjacent sets of welded connection groups 4 needs to meet certain requirements. As a result, due to the poor precision in the preparation of the welded connection structure 41, the height difference between different welded connection structures 41 is too large. This makes it easy for pressure differences to be generated between the welded connection structures 41 during the resistance welding process, resulting in a large difference in the area of ​​each weld mark. This makes it easy for the smaller weld mark area to melt and break, which is not conducive to the flow capacity.

[0065] In this example embodiment, the minimum spacing between two adjacent welded connection groups 4 is 'a', and the minimum spacing between the two furthest welded connection structures 41 within the same welded connection group 4 is 'd', where the value of a × d is greater than or equal to 4 mm. 2 Less than or equal to 68mm 2 For example, the value of a×d can be 6mm. 2 10mm 2 15mm 2 20mm 2 25mm 2 30mm 2 35mm², 40mm², 45mm 2 50mm 2 55mm 2 60mm 2 65mm 2 wait.

[0066] If the value of a×d is too small, resulting in a small minimum spacing 'a' between two adjacent welded connection groups 4, it will affect the already formed weld marks during subsequent resistance welding processes. For example, the current will flow directly through the already formed weld marks, making it difficult to form weld marks between the welded connection structure 41 and the tab 32 currently being resisted, and the already formed weld marks are prone to melting due to overcurrent. Alternatively, if the minimum spacing 'd' between the two furthest welded connection structures 41 is too small, heat will easily accumulate between the two welded connection structures 41 during welding, causing the two welded connection structures 41 to stick together.

[0067] If the value of a×d is too large, the minimum spacing a between two adjacent welding connection groups 4 will be too large, and a sufficient number of welding connection groups 4 cannot be set; or the minimum spacing d between the two farthest welding connection structures 41 will be too large. During the preparation of the welding connection structure 41, due to process errors, the height difference of the welding connection structure 41 will be too large. This will make it easy for a pressure difference to be generated between the welding connection structures 41 during the resistance welding process, resulting in a large difference in the area of ​​each weld mark. This will make it easy for the position with the smaller weld mark area to melt and break, which is not conducive to the flow capacity.

[0068] The above-mentioned numerical range not only avoids the impact of subsequent resistance welding processes on the already formed weld marks due to overcurrent melting, ensuring that weld marks are easily formed between the welded connection structure 41 and the tab 32 currently being resisted welded, thus ensuring the overcurrent capacity between the welded connection structure 41 and the tab 32; but also ensures that a sufficient number of welded connection groups 4 can be set up, ensuring that the height difference between each welded connection structure 41 is small, the pressure difference between the welded connection structures 41 is small during the resistance welding process, and the area of ​​each weld mark is relatively uniform, avoiding melting at some welded connection structures 41; and also avoiding adhesion between two adjacent welded connection structures 41.

[0069] Optionally, the minimum spacing a between two adjacent welded connection groups 4 is greater than or equal to 1 mm and less than or equal to 6 mm. For example, the minimum spacing a between two adjacent welded connection groups 4 can be 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm, 5 mm, 5.5 mm, etc.

[0070] Optionally, within the same welded connection group 4, the minimum distance d between the two furthest welded connection structures 41 is greater than or equal to 2 mm and less than or equal to 12 mm. For example, the minimum distance d between the two furthest welded connection structures 41 can be 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm, 5 mm, 5.5 mm, 6 mm, 6.5 mm, 7 mm, 7.5 mm, 8 mm, 8.5 mm, 9 mm, 9.5 mm, 10 mm, 10.5 mm, 11 mm, 11.5 mm, etc.

[0071] In some exemplary embodiments of this disclosure, the minimum spacing 'a' between two adjacent welded connection groups 4 is greater than the minimum spacing 'b' between two adjacent welded connection structures 41 belonging to the same welded connection group 4. This arrangement avoids affecting already welded welded connection groups 4 when welding a later welded connection group 4.

[0072] It should be noted that the minimum spacing b between two adjacent welded connection structures 41 within the same welded connection group 4 is the same as the minimum spacing b between two adjacent welded connection structures 41 belonging to the same welded connection group 4.

[0073] In some exemplary embodiments of this disclosure, within the same welded connection group 4, the minimum distance b between two adjacent welded connection structures 41 is greater than or equal to 0.5 mm and less than or equal to 4 mm. For example, the minimum distance b between two adjacent welded connection structures 41 can be 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, etc.

[0074] If the minimum spacing b between two adjacent welded connection structures 41 is too small, heat is likely to accumulate between the two adjacent welded connection structures 41 during welding, causing the two adjacent welded connection structures 41 to stick together.

[0075] If the minimum spacing b between two adjacent welded connection structures 41 is too large, it may result in an insufficient number of welded connection structures 41 being set. Moreover, during the preparation of the welded connection structure 41, due to process errors, the height difference of the welded connection structure 41 may be too large, which may cause a pressure difference between the welded connection structures 41 during the resistance welding process. This may result in a large difference in the area of ​​each weld mark, making it easy for the smaller weld mark area to melt and break, which is not conducive to the flow capacity.

[0076] The above numerical range not only ensures that the number of welded connection structures 41 meets the requirements and that the height difference between each welded connection structure 41 is small, but also that the pressure difference between the welded connection structures 41 is small during the resistance welding process, and that the weld area is relatively uniform, thus avoiding melting at some welded connection structures 41; it also prevents two adjacent welded connection structures 41 from sticking together.

[0077] In some exemplary embodiments of this disclosure, reference is made to Figure 3 and Figure 4 As shown, at least two welded connection structures 41 belonging to the same welded connection group 4 can be arranged in a straight line along the first direction X. For example, two, three, or more welded connection structures 41 belonging to the same welded connection group 4 can be arranged in a straight line along the first direction X. At least two groups of welded connection groups 4 can be arranged sequentially and parallel along the second direction Y. For example, two, three, or more groups of welded connection groups 4 can be arranged sequentially and parallel along the second direction Y.

[0078] This configuration reduces the space occupied by the welded connection group 4 in the second direction Y, thereby enabling the installation of two, three, or more welded connection groups 4 to ensure the current flow capacity between the welded connection structure 41 and the tab 32.

[0079] Of course, in some other exemplary embodiments of this disclosure, reference is made to Figure 6 As shown, three welded connection structures 41 belonging to the same welded connection group 4 can be arranged in a triangle, so at least two welded connection groups 4 can be arranged to form at least two triangles; the adjacent sides of at least two triangles are parallel, and one vertex of one triangle is collinear with the base of the adjacent triangle. At least two welded connection groups 4 can be arranged sequentially along the second direction Y, that is, at least two triangles are arranged sequentially along the second direction Y.

[0080] This arrangement allows multiple welded connection structures 41 to be concentrated, resulting in more concentrated pressure during resistance welding. Pressure differences between the welded connection structures 41 are less likely to occur, leading to smaller height differences and more uniform weld areas. This ensures more uniform current-carrying capacity for each welded connection structure 41. It also reduces the space occupied by the welded connection group 4 in the second direction Y, allowing for the setting of two, three, or more welded connection groups 4 to guarantee the current-carrying capacity between the welded connection structure 41 and the tab 32.

[0081] It should be noted that both the first direction X and the second direction Y are parallel to the side of the pole member 2 where the welding connection structure 41 is set, and the first direction X intersects the second direction Y. For example, the first direction X is perpendicular to the second direction Y.

[0082] A triangle can be an isosceles triangle, an equilateral triangle, a right triangle, or any other non-special triangle.

[0083] In addition, the above arrangement can be a pattern formed by connecting the center points of the welded connection structure 41.

[0084] In some exemplary embodiments of this disclosure, reference is made to Figure 4 As shown, the shape of the orthographic projection of the welded connection structure 41 on the first reference plane is circular, which makes the heat more evenly diffused during the resistance welding process, so that the weld mark formed is also basically circular, ensuring that the strength of the welded connection structure 41 and the tab 32 are uniform and the current carrying capacity is also uniform.

[0085] The first reference plane is parallel to the side of the pole post member 2 where the pole lug 32 is connected. Specifically, the first reference plane is parallel to the side of the pole post member 2 where the welding connection structure 41 is provided.

[0086] It should be noted that a circle can be not only a circle in the strict sense, but also an approximate circle with a certain degree of error. The error range varies depending on the equipment and preparation process. Therefore, within the error range of the equipment and preparation process, they are considered to be the same.

[0087] In some exemplary embodiments of this disclosure, reference is made to Figure 5 As shown, the orthographic projection of the welded connection structure 41 on the first reference plane has a dimension along the first direction X that is larger than its dimension along the second direction Y. For example, the orthographic projection of the welded connection structure 41 on the first reference plane can be a rectangle, and the long side of the rectangle extends along the first direction X, and the short side of the rectangle extends along the second direction Y.

[0088] Of course, in some other exemplary embodiments of this disclosure, the shape of the orthographic projection of the welded connection structure 41 on the first reference plane can be an ellipse, a parallelogram, or other regular or irregular shapes; generally, the shape of the orthographic projection of the welded connection structure 41 on the first reference plane can be consistent with the shape of the weld head.

[0089] In this case, the value of a×d is greater than or equal to 4mm. 2 Less than or equal to 66mm 2 Since the orthographic projection of the welded connection structure 41 on the first reference plane along the first direction X is larger than its dimension along the second direction Y, the area of ​​this welded connection structure 41 is reduced compared to a circular welded connection structure 41, i.e., the flow area is reduced. Therefore, the minimum spacing 'a' between two adjacent welded connection groups 4 can be appropriately reduced, or the minimum spacing 'd' between the two furthest welded connection structures 41 belonging to the same welded connection group 4 can be appropriately reduced. This can increase the number of welded connection groups 4 to compensate for the reduction in flow area.

[0090] Based on the same inventive concept, this disclosure provides an example embodiment of a battery device, which may include a battery case and a battery; the battery is any of the batteries described above, and the battery is disposed inside the battery case. The specific structure of the battery has been described in detail above, and therefore will not be repeated here.

[0091] In this example embodiment, the battery device may include a battery case, which may be configured as a cuboid structure; therefore, the battery case may also be configured as a cuboid structure. Specifically, the battery case may include a support plate, a protective cover, two first side frames, and two second side frames. The support plate and the protective cover may be rectangular. Two first side frames and two second side frames are provided around the support plate, connected end-to-end to form a rectangular frame. The first side frames extend along the width direction, and the second side frames extend along the length direction. A protective cover is provided on the opposite side of the two first side frames and two second side frames from the support plate, such that the protective cover is positioned opposite the support plate. The two first side frames and two second side frames are connected between the protective cover and the support plate. The support plate, the protective cover, the two first side frames, and the two second side frames surround and form the receiving cavity of the battery case.

[0092] Of course, in other exemplary embodiments of this disclosure, the support plate and protective cover can be circular, elliptical, trapezoidal, etc., and the side frame can be one or more, forming a circle, ellipse, trapezoid, etc., so that the battery box is formed as a cylinder, elliptical cylinder, prism, etc. In other embodiments, there may be no protective cover, and the battery box can be directly assembled to the vehicle chassis. The battery box can also be other shapes, which will not be described in detail here.

[0093] The battery pack disclosed herein, on the one hand, provides at least two sets of welding connection groups 4 to avoid the defect of insufficient current distribution at each welding connection structure 41 due to simultaneous welding of a large number of welding connection structures 41, which would prevent the generation of large weld marks; that is, it enables the weld mark area of ​​the welding connection structure 41 connected to the tab 32 to be larger, thereby improving the overcurrent capacity between the terminal member 2 and the tab 32, reducing heat generation, and avoiding thermal runaway due to severe heat generation during charging and discharging, thus improving the safety of the battery pack. On the other hand, this not only avoids the subsequent resistance welding process from causing the already formed weld marks to melt due to overcurrent, ensuring that the welded connection structure 41 currently undergoing resistance welding and the tab 32 can easily form weld marks to ensure the overcurrent capacity between the welded connection structure 41 and the tab 32; it also ensures that a sufficient number of welded connection groups 4 can be set up, ensuring that the height difference between each welded connection structure 41 is small, the pressure difference between the welded connection structures 41 is small during the resistance welding process, and the area of ​​each weld mark is relatively uniform, avoiding melting at some welded connection structures 41; and it also avoids the adhesion between two adjacent welded connection structures 41 to ensure the electrical performance of the battery pack.

[0094] The terms "parallel" and "perpendicular" used in this application can mean not only perfectly parallel and perpendicular, but also have a certain margin of error; for example, if the angle between the two is greater than or equal to 0° and less than or equal to 5°, they are considered to be parallel; if the angle between the two is greater than or equal to 85° and less than or equal to 95°, they are considered to be perpendicular.

[0095] Other embodiments of this disclosure will readily occur to those skilled in the art upon consideration of the specification and practice of the utility models disclosed herein. This application is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this disclosure are indicated by the appended claims.

Claims

1. A single-cell battery, characterized in that, include: pole post components; A battery cell includes a cell body and tabs, wherein the tabs are connected to the cell body; At least two sets of welded connection groups, each set comprising at least two welded connection structures, are connected between the pole member and the pole lug. The minimum distance between two adjacent sets of welded connection groups is 'a', and within the same set, the minimum distance between the two furthest welded connection structures is 'd', where a × d is greater than or equal to 4 mm. 2 Less than or equal to 68mm 2 .

2. The single-cell battery according to claim 1, characterized in that, The minimum spacing 'a' between two adjacent welded connection groups is greater than the minimum spacing 'b' between two adjacent welded connection structures belonging to the same welded connection group.

3. The single-cell battery according to claim 2, characterized in that, Within the same welded connection group, the minimum spacing b between two adjacent welded connection structures is greater than or equal to 0.5 mm and less than or equal to 4 mm.

4. The single-cell battery according to any one of claims 1 to 3, characterized in that, At least two of the welded connection structures belonging to the same welded connection group are arranged in a straight line along the first direction, and at least two groups of the welded connection groups are arranged sequentially and in parallel along the second direction. Alternatively, the three welded connection structures belonging to the same welded connection group are arranged in a triangle, with at least two of the triangles having parallel adjacent sides, and one vertex of one of the triangles being collinear with the base of the adjacent triangle, and at least two groups of welded connection groups being arranged sequentially along the second direction; Wherein, the first direction intersects with the second direction.

5. The single-cell battery according to claim 4, characterized in that, The shape of the orthographic projection of the welded connection structure on the first reference plane is circular; wherein, the first reference plane is parallel to the side of the pole member that connects to the pole lug.

6. The single-cell battery according to claim 4, characterized in that, The orthographic projection of the welded connection structure onto the first reference plane along the first direction is larger than its dimension along the second direction; wherein the first reference plane is parallel to the side of the pole member that connects to the pole lug.

7. The single-cell battery according to claim 6, characterized in that, The value of a×d is greater than or equal to 4mm 2 Less than or equal to 66mm 2 .

8. The single-cell battery according to any one of claims 1 to 3, characterized in that, The welding connection structure and the pole member are integrally formed. The welding connection structure is welded to the pole lug so that the welding connection structure and the pole lug are connected with a weld mark.

9. The single-cell battery according to any one of claims 1 to 3, characterized in that, The minimum spacing 'a' between two adjacent welded connection groups is greater than or equal to 1 mm and less than or equal to 6 mm.

10. A battery pack, characterized in that, include: Battery box; The single cell battery is the single cell battery according to any one of claims 1 to 9, wherein the single cell battery is disposed inside the battery box.

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