Short path battery adapted to large size stacked cells

Abstract

The application provides a short-path battery suitable for large-size stacked cells, which comprises a battery shell and a cell group sealedly assembled in the battery shell, and the outer surface of the cell group is covered with an insulation layer; the battery shell comprises a shell body, a cover plate assembly and an electrode terminal assembly; the inside of the shell body is formed with a cavity for accommodating the cell group; the cover plate assembly is assembled at the opening of the shell body and is provided with two terminal mounting holes at intervals; the electrode terminal assembly comprises a terminal holder and an electrode terminal; the terminal holder is embedded in the terminal mounting hole and used for fixing the electrode terminal on the cover plate assembly and insulating and isolating the electrode terminal from the cover plate assembly; the electrode terminal is fixedly penetrated in the terminal holder, the first end of the electrode terminal is located in the cavity and electrically connected with the tab of the cell group, and the second end is used for externally outputting electric energy. The application has the beneficial effects of significantly shortening the current transmission path, reducing or eliminating the intermediate connecting structure, reducing the contact resistance and Joule loss, releasing the wasted high space, and being suitable for large-size stacked cells.

Description

Technical Field

[0001] This invention belongs to the field of battery technology and relates to a short-path battery adapted to large-size stacked cells. Background Technology

[0002] New energy technologies, especially lithium-ion battery technology, have been widely used in energy storage systems, electric vehicles, and portable electronic devices. As the market continues to demand longer driving range, longer energy storage time, and higher device power, the size of individual battery cells is constantly increasing, placing increasingly stringent requirements on battery energy density (volume energy density and mass energy density) and energy efficiency (charge and discharge energy efficiency and rate performance).

[0003] In existing large-size laminated battery cell structures, the cell electrodes are typically arranged in a butterfly (or Z-shaped) stacking pattern. After the electrode units are stacked, the positive and negative tabs are led out from either side or the same side of the cell body. Subsequently, the tabs are electrically connected to the terminals (positive / negative terminals) on the cover plate via welded busbars. This structure is technically mature and relatively simple to manufacture in conventional-sized cells, but when applied to large-size laminated battery cells, it exhibits the following significant drawbacks:

[0004] (i) Low space utilization, resulting in redundant battery volume: In large-size stacked cells, the height of the tabs themselves can reach over 40mm. To complete the welding of the tabs to the connecting pieces, the tabs need to be bent (tab folding) so that the tab end faces the cover plate. This bending process requires at least 4mm of tab bending space (including the tab bending radius and clearance). In addition, the connecting pieces themselves have a certain thickness, and the welding of the connecting pieces to the cover plate terminals also requires a certain height. The combination of these factors results in the total height reaching over 8mm. This leads to a large amount of ineffective space occupation in the height direction of the battery. Given that the overall size of the battery (especially in the height direction) is limited by the space of standard modules or equipment, this design directly reduces the height range available to accommodate active materials, thereby sacrificing the theoretical upper limit of the battery capacity.

[0005] (II) Excessive current path leads to reduced energy efficiency and increased thermal management burden: In existing butterfly-shaped arrangement and connecting piece welding structures, after the current flows out from the active layer of the cell electrode, it must sequentially pass through: the uncoated area of ​​the tab, the bent section of the tab, the connecting piece, the terminal transition structure, and finally reach the cover plate terminal. This path involves multiple heterogeneous material interfaces (such as the welding interface between the tab and the connecting piece, and the welding interface between the connecting piece and the terminal), each introducing contact resistance. Simultaneously, the longer physical path also implies higher ohmic impedance (especially the uneven local current distribution and additional resistance generated by the bent section of the tab). Under large-size, high-rate charge / discharge conditions (such as energy storage frequency regulation, rapid acceleration / fast charging of electric vehicles), the longer current path will cause significant Joule heat loss, reducing the battery's charge / discharge energy efficiency (i.e., increasing energy dissipation during transmission). Furthermore, concentrated ohmic heat will exacerbate the temperature unevenness inside the battery, accelerate local aging, and affect the battery's cycle life and safety.

[0006] (III) High structural complexity and limited production yield: The butterfly-shaped arrangement requires precise positioning, bending, and shaping of the tabs before laser or ultrasonic welding with the connecting pieces. This involves numerous steps and demands high equipment precision and process stability. In large-size cells, the large number of tabs and the difficulty in alignment, coupled with the tendency for defects such as tab breakage, stacking misalignment, and incomplete welding during bending, lead to decreased production yield and increased manufacturing costs.

[0007] (iv) Poor compatibility of module level: Due to the above-mentioned height space occupation problem, when the batteries of this structure are assembled into battery packs or energy storage cabinets, additional insulation intervals and heat dissipation channels are often required to deal with local hot spots, which further reduces the volume utilization rate of the module level.

[0008] Therefore, there is an urgent need to develop a short-path battery that is compatible with large-size stacked cells. This battery should be able to significantly shorten the current transmission path, reduce or eliminate intermediate connection structures (such as connecting pieces), reduce contact resistance and Joule loss, and at the same time free up wasted height space, ultimately achieving a dual improvement in energy efficiency and energy density under large-size battery conditions. Summary of the Invention

[0009] To address the problems in the prior art, this application proposes a short-path battery that can significantly shorten the current transmission path, reduce or eliminate intermediate connection structures (such as connecting pieces), reduce contact resistance and Joule losses, and at the same time free up wasted height space, adapting to large-size stacked cells.

[0010] To solve the above problems, the technical solution adopted by the present invention is as follows:

[0011] This invention provides a short-path battery adapted to large-size stacked battery cells, comprising a battery casing and a battery cell assembly sealed and assembled within the battery casing. The outer surface of the battery cell assembly is covered with an insulating layer. The battery casing includes:

[0012] The housing has an internal cavity for housing the battery cell assembly;

[0013] A cover plate assembly, fitted at the opening of the housing, has two terminal mounting holes spaced apart thereon for leading out electrode terminals; and

[0014] An electrode terminal assembly includes a terminal holder and an electrode terminal. The terminal holder is embedded in the terminal mounting hole and is used to fix the electrode terminal to the cover plate assembly and insulate it from it. The electrode terminal is fixedly inserted in the terminal holder. The first end of the electrode terminal is located in the cavity and is electrically connected to the tab of the battery cell assembly. The second end of the electrode terminal is used to output electrical energy to the outside.

[0015] As a preferred embodiment of this application, the cover plate assembly includes:

[0016] The cover plate body includes an upper cover plate and a lower partition plate disposed at the bottom of the upper cover plate. The upper cover plate is provided with two first terminal mounting holes spaced apart, and the lower partition plate is provided with two second terminal mounting holes corresponding to the positions of the first terminal mounting holes. The first terminal mounting holes and the second terminal mounting holes are vertically connected to each other to form a terminal mounting hole.

[0017] A positioning frame, embedded in the terminal mounting hole and sleeved on the outside of the terminal retainer, has an outer edge extending upward to form an outer positioning flange for limiting and fixing the pressure frame; the inner edge extending downward to form an inner positioning flange, which is tightly inserted into the gap between the inner wall of the terminal mounting hole and the terminal retainer for clamping and limiting the terminal retainer; and

[0018] The fastener is assembled on the upper part of the positioning frame and sleeved on the terminal holder, and is confined within the annular area between the outer positioning flange and the terminal holder, for clamping and limiting the terminal holder.

[0019] As a preferred embodiment of this application, the cover plate assembly is further provided with a liquid injection channel, and an explosion-proof component is disposed at the liquid injection hole to form a seal for the liquid injection channel.

[0020] As a preferred embodiment of this application, the terminal mounting hole is a multi-stage stepped hole with gradually increasing diameter from top to bottom, which is used to form a limiting fit with the corresponding parts of the positioning frame and the electrode terminal assembly to achieve graded assembly.

[0021] As a preferred embodiment of this application, the inner edge of the second terminal mounting hole is integrally formed with a positioning step portion along the circumferential direction. The radial inner and outer sides of the positioning step portion are both stepped, wherein the inner step surface is used to limit the corresponding position of the terminal holder, and the outer step surface is used to limit the upper cover plate.

[0022] As a preferred embodiment of this application, both the positioning frame and the lower partition plate are made of plastic.

[0023] As a preferred embodiment of this application, a first welding groove is machined on the outer wall surface of the inner positioning flange.

[0024] As a preferred embodiment of this application, the bottom inner edge of the fastener is machined with a second welding groove along the circumferential direction.

[0025] As a preferred embodiment of this application, the terminal holder includes a first terminal holder and a second terminal holder, wherein the first terminal holder is electrically connected to the positive electrode tab of the battery cell through an electrode terminal, and the second terminal holder is electrically connected to the positive electrode tab of the battery cell through the remaining electrode terminals. The first terminal holder and the second terminal holder have the same structure but different materials; the first terminal holder is made of aluminum, and the second terminal holder is made of copper.

[0026] As a preferred embodiment of this application, the terminal retainer includes:

[0027] The base is used to secure the terminal retainer to the cover plate assembly;

[0028] A terminal retaining portion is integrally formed on the upper surface of the base and inserted into the cover plate assembly. The outer diameter of the terminal retaining portion is smaller than the outer diameter of the base, and its outer periphery is provided with multiple positioning steps adapted to the terminal mounting holes. These positioning steps are also adapted to the inner wall of the cover plate assembly.

[0029] At least one terminal channel, the terminal channel extending through the base and the terminal holding portion, is used to accommodate and position the electrode terminal;

[0030] The terminal retainer, after being inserted into the cover plate assembly, is adapted to the inner wall of the corresponding terminal mounting hole.

[0031] As a preferred embodiment of this application, the outer surface of the terminal holding part has a two-stage stepped structure with a smaller upper part and a larger lower part, wherein the first stage is adapted to the inner hole of the fixing member, and the second stage is adapted to the inner hole of the positioning frame.

[0032] As a preferred embodiment of this application, along the battery height direction, the heights of the upper surface of the terminal holding part, the upper surface of the fixing member, the upper surface of the positioning frame, and the upper surface of the cover plate body decrease successively, forming a multi-level stepped structure with distinct layers.

[0033] Preferably, the upper sidewall of the terminal retaining portion is machined with a third welding groove. The bottom of the third welding groove is flush with the upper surface of the fixing member. Furthermore, the third welding groove is located at the top of the first step.

[0034] As a preferred embodiment of this application, the two ends of the terminal channel are respectively machined with an upper positioning ring and a lower positioning ring for fitting with the electrode terminals.

[0035] As a preferred embodiment of this application, an annular sealing ring is provided between the terminal retainer and the cover plate assembly.

[0036] As a preferred embodiment of this application, the electrode terminals include:

[0037] A conductive substrate, wherein the conductive substrate has recessed platforms on both sides in the thickness direction of the battery cell, and the depth of the recessed platforms matches the stacking thickness of the tabs of a single battery cell in the battery cell assembly; and

[0038] A conductive block disposed on the conductive substrate, the upper end of the conductive block passing through the terminal channel and exposed to the outside, is used to output electrical energy to the outside.

[0039] As a preferred embodiment of this application, the conductive block has a two-stage stepped structure with a smaller upper step and a larger lower step. The upper step of the conductive block is adapted to the terminal channel, and the lower step of the conductive block is adapted to the lower positioning ring platform. The height of the upper step is equal to the distance between the upper and lower positioning ring platforms of the terminal channel.

[0040] As a preferred embodiment of this application, the battery cell assembly consists of multiple battery cells, with each pair of battery cells forming a group. These groups are connected in parallel via two sets of electrode terminal assemblies. One electrode terminal assembly is connected to the tab of the positive electrode of the battery cell, and the other electrode terminal assembly is connected to the tab of the negative electrode of the battery cell. The maximum conductive path length between the tab of each battery cell and the first end of the electrode terminal is less than one-third of the thickness of a single battery cell in the battery cell assembly.

[0041] The assembly method of the battery of the present invention is as follows:

[0042] Let's take a battery pack consisting of four cells as an example:

[0043] 1. Cell pretreatment and tab welding:

[0044] After ultrasonically welding the positive and negative tabs of each battery cell, they are cut and shaped. Two batteries processed in the above manner are arranged in a butterfly pattern on both sides of the electrode terminal assembly, with the positive tab of the battery cell welded to the lower step of one set of electrode terminals, and the negative tab welded to the lower step of another set of electrode terminals. Then, the cells are joined together.

[0045] 2. Sealing ring installation and cell assembly:

[0046] After the cores are assembled, the sealing ring is placed on the electrode terminal, pressing the bottom surface of the sealing ring against the lower protrusion of the electrode terminal, with the terminal retainer passing through the sealing ring. The four assembled cells are arranged side-by-side, with the upper step of the electrode terminal inserted into the terminal channel, ensuring the top surface of the electrode terminal is flush with the surface of the upper positioning ring of the terminal retainer. Then, the electrode terminal is welded to the third welding groove of the terminal retainer.

[0047] 3. Pre-assembly of the housing and cover:

[0048] After welding, an insulating layer is wrapped around the four battery cells, and then they are placed into the housing.

[0049] Assembly of 4-terminal retainer:

[0050] The first terminal retainer is inserted sequentially from bottom to top into the second terminal mounting hole of the lower isolation plate, the sealing ring, the first terminal mounting hole of the upper cover plate, the positioning frame, and the fixing member. After assembly, the inner positioning flange of the positioning frame is tightly inserted into the gap between the inner wall of the terminal mounting hole and the terminal retainer; the fixing member is confined within the annular area between the outer positioning flange and the terminal retainer; the sealing ring is confined between the terminal retainer and the cover plate assembly. While maintaining mechanical clamping, the first step of the terminal retainer is welded to the fixing member, completing the assembly of the first terminal retainer. Similarly, the second terminal retainer is inserted sequentially from bottom to top into the second terminal mounting hole of the lower isolation plate, the sealing ring, the first terminal mounting hole of the upper cover plate, the positioning frame, and the fixing member, and the same positioning, clamping, and welding steps are completed to complete the assembly of the second terminal retainer.

[0051] 5. Final assembly form:

[0052] After assembly, along the height direction of the battery, the height of the upper surface of the terminal holding part, the upper surface of the fixing member, the upper surface of the positioning frame, and the upper surface of the cover plate body decreases successively, forming a multi-level stepped structure with distinct layers; at the same time, the bottom of the third welding groove of the terminal holding part is flush with the upper surface of the corresponding fixing member to facilitate welding operation.

[0053] Compared with the prior art, the beneficial effects of the present invention are:

[0054] 1. Shortened current path and improved energy efficiency: This application enables direct conduction between the electrode terminals and the cell tabs, eliminating the connecting pieces and tab bending of traditional structures, thus significantly shortening the current transmission path. Furthermore, the maximum conductive path between a single cell tab and the electrode terminal is less than one-third of the cell thickness, effectively reducing battery internal resistance and Joule heat loss, and significantly improving charge and discharge energy efficiency.

[0055] 2. Free up height space and increase energy density: Eliminate the height space occupied by the tab bending (current technology requires more than 4mm) and the thickness of the connecting piece, so that more height inside the casing can be used to accommodate the active material of the cell. More cell layers can be installed in the same external size, thereby increasing the volumetric energy density and gravimetric energy density of the battery.

[0056] 3. A graded assembly structure for high-precision positioning: The terminal mounting holes employ a multi-stage stepped design with gradually increasing diameters from top to bottom. This, combined with the inner and outer positioning flanges and fixing components of the positioning frame, forms a graded limiting and clamping structure. This design provides assembly guidance, prevents axial movement and radial deflection, and ensures the positional accuracy of the electrode terminals and tabs during mating.

[0057] 4. Multi-stage positioning surfaces enhance assembly stability: The terminal retainer has multiple positioning steps on its outer periphery, which complement each other with the multi-stage stepped holes, applying uniform constraint force to the terminal retainer and preventing stress concentration or loosening. The outer diameter of the base is larger than the outer diameter of the terminal retainer, and together with the annular sealing ring, reliable sealing and long-term anchoring are achieved.

[0058] 5. Recessed platform design to reduce contact resistance: The electrode terminals are equipped with recessed platforms on both sides that match the thickness of the stacked tabs, so that the tabs fit smoothly, increase the effective contact area, reduce contact resistance, reduce energy loss, and improve connection strength.

[0059] 6. Parallel connection of multiple cells to optimize space utilization: Multiple cells are connected in parallel in pairs through two sets of electrode terminal assemblies, which distributes the current evenly, reduces intermediate connecting parts such as busbars, and improves the space utilization of the module level. Attached Figure Description

[0060] Figure 1 This is a schematic diagram of the battery of the present invention after an explosion.

[0061] Figure 2 This is an exploded view of the cover plate assembly and electrode terminal assembly of the battery of the present invention.

[0062] Figure 3 This is one of the structural schematic diagrams of the battery fixing component of the present invention.

[0063] Figure 4 This is a second schematic diagram of the structure of the battery fixing component of the present invention.

[0064] Figure 5 This is one of the structural schematic diagrams of the positioning frame of the battery according to the present invention.

[0065] Figure 6 This is a second schematic diagram of the positioning frame of the battery according to the present invention.

[0066] Figure 7 This is one of the structural schematic diagrams of the top cover plate of the battery of the present invention.

[0067] Figure 8 This is a second schematic diagram of the structure of the top cover plate of the battery of the present invention.

[0068] Figure 9 This is one of the structural schematic diagrams of the lower separator plate of the battery of the present invention.

[0069] Figure 10 This is a second schematic diagram of the lower separator plate of the battery of the present invention.

[0070] Figure 11 This is one of the structural schematic diagrams of the terminal positioner of the present invention.

[0071] Figure 12 This is a second schematic diagram of the terminal positioner of the present invention.

[0072] Figure 13 This is one of the structural schematic diagrams of the electrode terminals of the present invention.

[0073] Figure 14 This is a schematic diagram of the sealing ring of the present invention.

[0074] Figure 15 This is a schematic diagram of the two battery cells of the present invention unfolded.

[0075] Figure 16 This is a schematic diagram of the two battery cells combined according to the present invention.

[0076] Figure 17 for Figure 16 A magnified view of a portion of the image.

[0077] Figure 18 This is a schematic diagram showing the positions of the battery cell and cover plate assembly of the present invention.

[0078] Figure 19 This is a top view of the battery cell and cover plate assembly of the present invention.

[0079] Figure 20 for Figure 19 A three-dimensional sectional view of the AA position.

[0080] Figure 21 for Figure 19 AA sectional view.

[0081] Figure 22 for Figure 21 A magnified view of a portion of the image.

[0082] Figure 23 for Figure 20 One of the magnified views of a section.

[0083] Figure 24 for Figure 20 The second enlarged view of a part.

[0084] In the diagram: 1. Battery casing; 2. Cell assembly; 21. Cell; 211. Tab; 22. Insulation layer; 3. Housing; 4. Cover assembly; 41. Cover body; 411. Upper cover; 412. Lower separator plate; 4121. Separator positioning boss; 4122. Recessed platform; 413. Terminal mounting hole; 4131. First terminal mounting hole; 4132. Second terminal mounting hole; 4133. Upper welding groove; 4134. Lower welding groove; 42. Positioning frame; 421. Outer positioning flange; 422. Inner positioning flange; 43. 431. Fixing component; 44. Second welding groove; 44. Liquid injection channel; 441. First liquid injection hole; 442. Second liquid injection hole; 45. Explosion-proof component; 46. Sealing ring; 5. Electrode terminal assembly; 51. Terminal retainer; 511. Base; 512. Terminal retaining part; 5121. First step; 5122. Second step; 513. Terminal channel; 5131. Upper positioning ring platform; 5132. Lower positioning ring platform; 52. Electrode terminal; 521. Conductive substrate; 5211. Recessed platform; 522. Conductive block. Detailed Implementation

[0085] The following specific examples illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. This application can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application.

[0086] It should be noted that the process equipment or apparatus not specifically mentioned in the following embodiments are all conventional equipment or apparatus in the art.

[0087] Furthermore, it should be understood that the existence of other method steps before or after the combined steps, or the insertion of other method steps between these explicitly mentioned steps, does not preclude the existence of other method steps before or after the combined steps, or the insertion of other method steps between these explicitly mentioned steps, unless otherwise stated. It should also be understood that the combined connection relationship between one or more devices / apparatus mentioned in this application does not preclude the existence of other devices / apparatus before or after the combined devices / apparatus, or the insertion of other devices / apparatus between these explicitly mentioned devices / apparatus, unless otherwise stated. Moreover, unless otherwise stated, the numbering of each method step is merely a convenient tool for identifying each method step, and not for limiting the order of the method steps or limiting the scope of implementation of this application. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of implementation of this application.

[0088] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0089] In the description of this application, it should be understood that the terms "upper," "lower," "left," "right," "inner," "outer," "axial," and "circumferential," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are used only for the convenience of describing this application 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, and therefore should not be construed as a limitation of this application. Furthermore, features defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0090] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0091] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is 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. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0092] The present application will be further described below with reference to specific embodiments, but the scope of protection of the present application is not limited thereto.

[0093] like Figure 1 As shown, the present invention provides a short-path battery adapted to large-size stacked cells, including a battery casing 1 and a cell assembly 2 sealed and assembled within the battery casing 1. The outer surface of the cell assembly 2 is covered with an insulating layer 22. The battery casing 1 includes:

[0094] The housing 3 has an internal cavity for housing the battery cell assembly 2;

[0095] The cover plate assembly 4 is fitted into the opening of the housing 3, and has two terminal mounting holes 413 spaced apart thereon for leading out electrode terminals 52; and

[0096] The electrode terminal assembly 5 includes a terminal holder 51 and an electrode terminal 52. The terminal holder 51 is embedded in the terminal mounting hole 413 and is used to fix the electrode terminal 52 to the cover plate assembly 4 and insulate it from it. The electrode terminal 52 is fixedly inserted into the terminal holder 51. The first end of the electrode terminal 52 is located in the cavity and is electrically connected to the tab 211 of the battery cell assembly 2. The second end of the electrode terminal 52 is located on the outside of the cover plate assembly 4 and is used to output electrical energy to the outside.

[0097] like Figures 1-14 As shown, the cover plate assembly 4 includes:

[0098] The cover plate body 41 includes an upper cover plate 411 and a lower partition plate 412 disposed at the bottom of the upper cover plate 411. The upper cover plate 411 is provided with two first terminal mounting holes 4131 spaced apart. The lower partition plate 412 is provided with two second terminal mounting holes 4132 corresponding to the positions of the first terminal mounting holes 4131. The first terminal mounting holes 4131 and the second terminal mounting holes 4132 are vertically connected to each other to form a terminal mounting hole 413.

[0099] A positioning frame 42 is embedded in the terminal mounting hole 413 and sleeved on the outside of the terminal holder 51. The outer edge of the positioning frame 42 extends upward to form an outer positioning flange 421 for limiting and fixing the pressure frame; the inner edge of the positioning frame 42 extends downward to form an inner positioning flange 422, which is tightly inserted into the gap between the inner wall of the terminal mounting hole 413 and the terminal holder 51 for clamping and limiting the terminal holder 51; and

[0100] The fixing member 43 is assembled on the upper part of the positioning frame 42 and sleeved on the terminal holder 51, and is restricted within the annular area between the outer positioning flange 421 and the terminal holder 51, for clamping and limiting the terminal holder 51.

[0101] like Figure 1 , Figure 2 As shown, the cover plate assembly 4 is also provided with an injection channel 44, and an explosion-proof component 45 is disposed at the injection channel 44 to seal the injection hole.

[0102] like Figure 1 , Figure 2As shown, the upper cover plate 411 is provided with a first injection hole 441, and the lower isolation plate 412 is provided with a plurality of second injection holes 442, and the first injection hole and the plurality of second injection holes together form an injection channel; the explosion-proof component is assembled at the first injection hole.

[0103] like Figure 9 , Figure 10 , Figure 24 As shown, the lower isolation plate 412 is provided with a recessed platform 4122, and a plurality of second injection holes 442 are distributed on the recessed platform 4122. The recessed platform 4122 is located directly below the first injection hole 441, so that a buffer cavity is formed between the upper cover plate and the lower isolation plate. During the injection process, it can buffer and stabilize the liquid flow, and avoid excessive liquid flow force from affecting the injection accuracy.

[0104] like Figure 9 , Figure 10 , Figure 24 As shown, the orthographic projection of the first injection hole 441 on the lower isolation plate 412 falls completely within the area enclosed by the sunken platform 4122, ensuring that the liquid injected from the first injection hole can accurately fall into the buffer cavity formed by the sunken platform.

[0105] like Figure 20 , Figure 21 , Figure 22 , Figure 23 and Figure 24 As shown, the terminal mounting hole 413 is a multi-stage stepped hole with gradually increasing diameter from top to bottom, which is used to form a limiting fit with the corresponding parts of the positioning frame 42 and the electrode terminal assembly 5 to achieve graded assembly.

[0106] like Figure 7 As shown, the inner edge of the second terminal mounting hole 4132 is integrally formed with a positioning step portion 4133 along the circumferential direction. The positioning step portion 4133 has a stepped shape on both the inner and outer radial sides. The inner step surface is used to limit the corresponding position of the terminal holder 51, and the outer step surface is used to limit the upper cover plate 411.

[0107] In some embodiments of this application, the positioning frame and the lower partition plate are both plastic parts.

[0108] like Figure 8 As shown, the upper cover plate 411 has an upper welding groove 4133 and a lower welding groove 4134 processed on its upper and lower sides, wherein the upper welding groove 4133 and the lower welding groove 4134 are both arranged around the periphery of the first terminal mounting hole 4131.

[0109] like Figure 9 , Figure 10As shown, the upper surface of the lower isolation plate 412 is machined with a partition positioning boss 4121, which is arranged around the periphery of the second terminal mounting hole 4132.

[0110] In some embodiments of this application, a first welding groove is machined on the outer wall surface of the inner positioning flange.

[0111] like Figure 4 As shown, the bottom inner edge of the fastener 43 is machined with a second welding groove 431 along the circumferential direction.

[0112] In some embodiments of this application, the terminal holder includes a first terminal holder and a second terminal holder, wherein the first terminal holder is electrically connected to the positive electrode tab of the battery cell through an electrode terminal, and the second terminal holder is electrically connected to the positive electrode tab of the battery cell through the remaining electrode terminals. The first terminal holder and the second terminal holder have the same structure but different materials; the first terminal holder is made of aluminum, and the second terminal holder is made of copper.

[0113] like Figure 11 , Figure 12 As shown, the terminal holder 51 includes:

[0114] The base 511 is used to fix the terminal holder 51 to the cover plate assembly 4;

[0115] A terminal holding portion 512 is integrally formed on the upper surface of the base 511 and inserted into the cover plate assembly 4. The outer diameter of the terminal holding portion 512 is smaller than the outer diameter of the base 511, and its outer periphery is provided with a plurality of positioning steps adapted to the terminal mounting holes 413. The plurality of positioning steps are adapted to the inner wall of the cover plate assembly 4.

[0116] At least one terminal channel 513 extends through the base 511 and the terminal holding portion 512, and is used to accommodate and position the electrode terminal 52;

[0117] The terminal retainer 51 is adapted to the inner wall of the corresponding terminal mounting hole 413 after being inserted into the cover plate assembly 4.

[0118] like Figure 11 As shown, the outer surface of the terminal holding part 512 has a two-stage stepped structure with a smaller upper part and a larger lower part. The first-stage step 5121 is adapted to the inner hole of the fixing member, and the second-stage step 5122 is adapted to the inner hole of the positioning frame.

[0119] like Figure 11 , Figure 12 As shown, the top of the terminal holding part 512 is also provided with a third welding groove 5123.

[0120] like Figures 22-24 As shown, along the height direction of the battery, the heights of the upper surface of the terminal holding part 512, the upper surface of the fixing member 43, the upper surface of the positioning frame 42, and the upper surface of the cover plate body 41 decrease successively, forming a multi-level stepped structure with distinct layers.

[0121] like Figure 11 , Figure 12 As shown, the two ends of the terminal channel 513 are respectively machined with an upper positioning ring 5131 and a lower positioning ring 5132 for matching with the electrode terminals.

[0122] like Figure 1 As shown, an annular sealing ring 46 is provided between the terminal retainer 51 and the cover plate assembly 4.

[0123] like Figure 13 , Figure 14 As shown, the electrode terminal 52 includes:

[0124] A conductive substrate 521 has recessed platforms 5211 on both sides in the cell thickness direction, and the depth of the recessed platforms 5211 matches the tab stacking thickness of a single cell 21 in the cell assembly 2; and

[0125] The conductive block 522 is disposed on the conductive substrate 521. The upper end of the conductive block 522 passes through the terminal channel 513 and is exposed to the outside for outputting electrical energy.

[0126] like Figure 13 As shown, the conductive block 522 has a two-stage stepped structure with a smaller upper step and a larger lower step. The upper step 5221 of the conductive block 522 is adapted to the terminal channel, and the lower step 5222 of the conductive block 522 is adapted to the lower positioning ring platform. The height of the upper step is equal to the distance between the upper positioning ring platform and the lower positioning ring platform of the terminal channel.

[0127] like Figure 1 As shown, the battery cell assembly 2 consists of multiple battery cells 21. Each pair of battery cells 21 forms a group, and they are connected in parallel through two sets of electrode terminal assemblies 52. One electrode terminal assembly 52 is connected to the tab of the positive electrode of the battery cell 21, and the other electrode terminal assembly 52 is connected to the tab of the negative electrode of the battery cell 21. The maximum conductive path length between the tab of each battery cell 21 and the first end of the electrode terminal 52 is less than one-third of the thickness of a single battery cell 21 in the battery cell assembly 2.

[0128] The assembly method of the battery of the present invention is as follows:

[0129] Let's take a battery pack consisting of four cells as an example:

[0130] 1. Cell pretreatment and electrode tab welding:

[0131] After ultrasonically welding the positive and negative tabs of each battery cell, they are cut and shaped. Two batteries processed in the above manner are arranged in a butterfly pattern on both sides of the electrode terminal assembly, with the positive tab of the battery cell welded to the lower step of one set of electrode terminals, and the negative tab welded to the lower step of another set of electrode terminals. Then, the cells are joined together.

[0132] 2. Sealing ring installation and cell assembly:

[0133] After the cores are assembled, the sealing ring is placed on the electrode terminal, pressing the bottom surface of the sealing ring against the lower protrusion of the electrode terminal, with the terminal retainer passing through the sealing ring. The four assembled cells are arranged side-by-side, with the upper step of the electrode terminal inserted into the terminal channel, ensuring the top surface of the electrode terminal is flush with the surface of the upper positioning ring of the terminal retainer. Then, the electrode terminal is welded to the third welding groove of the terminal retainer.

[0134] 3. Pre-assembly of the housing and cover plate:

[0135] After welding, an insulating layer is wrapped around the four battery cells, and then they are placed into the housing.

[0136] 4. Assembly of terminal retainers:

[0137] The first terminal retainer is inserted sequentially from bottom to top into the second terminal mounting hole of the lower isolation plate, the sealing ring, the first terminal mounting hole of the upper cover plate, the positioning frame, and the fixing member. After assembly, the inner positioning flange of the positioning frame is tightly inserted into the gap between the inner wall of the terminal mounting hole and the terminal retainer; the fixing member is confined within the annular area between the outer positioning flange and the terminal retainer; the sealing ring is confined between the terminal retainer and the cover plate assembly. While maintaining mechanical clamping, the first step of the terminal retainer is welded to the fixing member, completing the assembly of the first terminal retainer. Similarly, the second terminal retainer is inserted sequentially from bottom to top into the second terminal mounting hole of the lower isolation plate, the sealing ring, the first terminal mounting hole of the upper cover plate, the positioning frame, and the fixing member, and the same positioning, clamping, and welding steps are completed to complete the assembly of the second terminal retainer.

[0138] 5. Final assembly form:

[0139] After assembly, along the height direction of the battery, the height of the upper surface of the terminal holding part, the upper surface of the fixing member, the upper surface of the positioning frame, and the upper surface of the cover plate body decreases successively, forming a multi-level stepped structure with distinct layers; at the same time, the bottom of the third welding groove of the terminal holding part is flush with the upper surface of the corresponding fixing member to facilitate welding operation.

[0140] The battery of this application can shorten the length of the cut tabs to 20mm. With the short-path conductive path design, the overall conductive path length from the cell tabs to the electrode terminals is shortened by nearly two-thirds compared with the traditional structure, which can significantly reduce the internal resistance of the battery and increase the battery capacity by more than 2% compared with the battery prepared by the traditional process.

[0141] The above embodiments are for illustrating the implementation schemes disclosed in this invention and should not be construed as limiting the invention. Furthermore, various modifications listed herein, as well as variations in the methods and compositions of the invention, will be apparent to those skilled in the art without departing from the scope and spirit of the invention. Although the invention has been specifically described in conjunction with various specific preferred embodiments, it should be understood that the invention should not be limited to these specific embodiments. In fact, various modifications as described above that are obvious to those skilled in the art to obtain the invention should be included within the scope of this invention.

Claims

1. A short-path battery adapted to large-size stacked cells, comprising a battery casing (1) and a cell assembly (2) sealed and assembled within the battery casing (1), wherein the outer surface of the cell assembly (2) is covered with an insulating layer (22), characterized in that, The battery casing (1) includes: The housing (3) has an interior cavity for housing the battery cell assembly (2); A cover plate assembly (4) is fitted into the opening of the housing (3), and has two terminal mounting holes (413) spaced apart thereon for leading out electrode terminals (52); and The electrode terminal assembly (5) includes a terminal holder (51) and an electrode terminal (52). The terminal holder (51) is embedded in the terminal mounting hole (413) and is used to fix the electrode terminal (52) on the cover plate assembly (4) and insulate it from it. The electrode terminal (52) is fixedly inserted in the terminal holder (51). The first end of the electrode terminal (52) is located in the cavity and is electrically connected to the tab of the battery cell assembly (2). The second end of the electrode terminal (52) is used to output electrical energy to the outside.

2. The short-path battery adapted to large-size stacked cells according to claim 1, characterized in that, The cover plate assembly (4) includes: The cover plate body (41) includes an upper cover plate (411) and a lower partition plate (412) disposed at the bottom of the upper cover plate (411). The upper cover plate (411) is provided with two first terminal mounting holes (4131) spaced apart. The lower partition plate (412) is provided with two second terminal mounting holes (4132) corresponding to the positions of the first terminal mounting holes (4131). The first terminal mounting holes (4131) and the second terminal mounting holes (4132) are vertically connected to form a terminal mounting hole (413). A positioning frame (42) is embedded in the terminal mounting hole (413) and sleeved on the outside of the terminal holder (51). The outer edge of the positioning frame (42) extends upward to form an outer positioning flange (421) for limiting and fixing the pressure frame; the inner edge of the positioning frame (42) extends downward to form an inner positioning flange (422). The inner positioning flange (422) is tightly inserted into the gap between the inner wall of the terminal mounting hole (413) and the terminal holder (51) for clamping and limiting the terminal holder (51); and The fastener (43) is assembled on the upper part of the positioning frame (42) and sleeved on the terminal holder (51), and is restricted within the annular area between the outer positioning flange (421) and the terminal holder (51) for clamping and limiting the terminal holder (51).

3. The short-path battery adapted for large-size stacked cells according to claim 1 or 2, characterized in that, The cover plate assembly (4) is also provided with a liquid injection hole (44), and an explosion-proof component (45) is provided at the liquid injection hole (44) to form a seal for the liquid injection hole.

4. The short-path battery adapted for large-size stacked cells according to claim 1 or 2, characterized in that, The terminal mounting hole (413) is a multi-stage stepped hole with gradually increasing diameter from top to bottom, which is used to form a limiting fit with the corresponding parts of the positioning frame (42) and the electrode terminal assembly (5) to achieve graded assembly.

5. The short-path battery adapted to large-size stacked cells according to claim 2, characterized in that, The inner edge of the second terminal mounting hole (4132) is integrally formed with a positioning step (4133) along the circumferential direction. The positioning step (4133) is stepped on both the inner and outer sides in the radial direction. The inner step surface is used to limit the corresponding position of the terminal holder (51), and the outer step surface is used to limit the upper cover plate (411).

6. The short-path battery adapted to large-size stacked cells according to claim 1, characterized in that, The terminal retainer (51) includes: The base (511) is used to fix the terminal retainer (51) to the cover plate assembly (4); A terminal retaining part (512) is integrally formed on the upper surface of the base (511) and inserted into the cover plate assembly (4). The outer diameter of the terminal retaining part (512) is smaller than the outer diameter of the base (511), and its outer periphery is provided with a plurality of positioning steps adapted to the terminal mounting holes (413). The plurality of positioning steps are adapted to the inner wall of the cover plate assembly (4). At least one terminal channel (513) extends through the base (511) and the terminal holding portion (512) for accommodating and positioning the electrode terminal (52). The terminal retainer (51) is adapted to the inner wall of the corresponding terminal mounting hole (413) after being inserted into the cover plate assembly (4).

7. The short-path battery adapted to large-size stacked cells according to claim 6, characterized in that, Along the height direction of the battery, the heights of the upper surface of the terminal holding part (512), the upper surface of the fixing member (43), the upper surface of the positioning frame (42), and the upper surface of the cover plate body (41) decrease successively, forming a multi-level stepped structure with distinct layers.

8. The short-path battery adapted to large-size stacked cells according to claim 1, characterized in that, An annular sealing ring (46) is provided between the terminal retainer (51) and the cover plate assembly (4).

9. The short-path battery adapted to large-size stacked cells according to claim 1, characterized in that, The electrode terminal (52) includes: A conductive substrate (521) has recessed platforms (5211) on both sides in the cell thickness direction, and the depth of the recessed platforms (5211) matches the tab stacking thickness of a single cell (21) in the cell assembly (2); and The conductive block (522) disposed on the conductive substrate (521) has its upper end penetrating through the terminal channel (513) and exposed to the outside for outputting electrical energy.

10. The short-path battery adapted to large-size stacked cells according to claim 1, characterized in that, The battery cell assembly (2) consists of multiple battery cells (21). Each pair of battery cells (21) forms a group and is connected in parallel through two sets of electrode terminal (52) assemblies (13). One electrode terminal assembly (13) is connected to the tab of the positive electrode of the battery cell (21), and the other electrode terminal assembly (5) is connected to the tab of the negative electrode of the battery cell (21). The maximum conductive path length between the tab of each battery cell (21) and the first end of the electrode terminal (52) is less than one-third of the thickness of a single battery cell (21) in the battery cell assembly (2).

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