Special-shaped tab, soft package battery, electric vehicle and preparation method of soft package battery

Abstract

The invention provides a special-shaped tab, a soft package battery, an electric vehicle and a preparation method of the soft package battery, and relates to the technical field of new energy batteries. The special-shaped tab comprises a bottom plate and a tab outer edge, one end of the tab outer edge is connected with the outer edge of the bottom plate, the tab outer edge is arranged in the circumferential direction of the bottom plate, and the bottom plate is used for being welded and fixed to an electrode end of a battery cell. According to the special-shaped tab, the soft package battery, the electric vehicle and the preparation method of the soft package battery, the special-shaped tab comprises the bottom plate and the tab outer edge arranged around the bottom plate, the bottom plate is used for being connected with the electrode end of the battery cell, and the current of the battery cell is transmitted outwards through the tab outer edge, so that the tab width and the sectional area of the battery cell are increased, and the overcurrent capacity of the battery is improved; the outer edge of the tab is connected with the bottom plate to form a three-dimensional structure, and the outer edge of the tab is generally flush with the outer wall of the battery cell during packaging, so that the thickness of the soft package battery is not limited by the depth of a punching pit of a soft package material, and the capacity of the soft package battery is favorably improved.

Description

Technical Field

[0001] This invention relates to the field of new energy battery technology, and in particular to a method for preparing a shaped electrode tab, a pouch battery, an electric vehicle, and a pouch battery. Background Technology

[0002] Soft-pack batteries use a thin aluminum-plastic film as the main material. The aluminum-plastic film is lightweight and thin, which helps reduce the weight of auxiliary materials in the battery composition, resulting in a relatively high energy density for soft-pack batteries. The aluminum-plastic film mainly consists of three layers: the outermost layer is a nylon / PET layer, primarily for exterior protection; the middle layer is an aluminum layer, which uses the natural advantage of metallic bonds to prevent the permeation of moisture, oxygen, and other materials; the innermost layer is CPP (cast polypropylene), mainly for heat-sealing. Due to the limitations of the aluminum-plastic film's cutting depth, the thickness of soft-pack batteries generally does not exceed 15mm, and the capacity is not very large. Furthermore, the current transfer between the inside and outside of soft-pack batteries is generally through the tabs. Traditional tabs are generally thin, and their width is limited by the width of the battery cell, resulting in a small cross-sectional area. This poses a risk of rapid heat generation and high temperatures during fast charging or discharging. Summary of the Invention

[0003] This invention provides an irregularly shaped electrode tab, a pouch battery, an electric vehicle, and a method for preparing a pouch battery, in order to solve the defects in the prior art where the capacity of pouch batteries is limited by the depth of the aluminum-plastic film perforation, and the small cross-sectional area of ​​the electrode tab leads to rapid heat generation during fast charging and discharging.

[0004] The present invention provides an irregularly shaped electrode tab, including a base plate and an outer edge of the electrode tab. One end of the outer edge of the electrode tab is connected to the outer edge of the base plate. The outer edge of the electrode tab is arranged circumferentially around the base plate. The base plate is used for welding and fixing to the electrode terminals of the battery cell.

[0005] According to the present invention, an irregularly shaped electrode tab is provided on the outer side of the outer edge of the electrode tab.

[0006] According to the present invention, a non-circular electrode tab is provided on the base plate, wherein the recessed direction of the recess is consistent with the extending direction of the outer edge of the electrode tab.

[0007] According to the present invention, the base plate and the outer edge of the electrode tab are integrally formed.

[0008] The present invention also provides a soft-pack battery, which includes a battery cell and irregularly shaped tabs as described above, wherein the base plate is welded and fixed to the electrode terminals of the battery cell.

[0009] This invention also provides an electric vehicle that includes a pouch battery as described above.

[0010] This invention also provides a method for preparing a pouch cell, comprising:

[0011] The positive and negative terminals of the battery cell are welded and fixed to the base plate of a non-standard electrode tab;

[0012] The battery cell and the irregularly shaped tabs are covered with a soft-pack material, with an air pocket provided; the soft-pack material is pre-sealed at both ends near the battery cell.

[0013] The outer edge of the tab is sealed to the soft packaging material by hot pressing.

[0014] According to a manufacturing method provided by the present invention, the step of welding and fixing the positive and negative terminals of the battery cell to the base plate of the irregularly shaped electrode tab specifically includes:

[0015] The current collector of the battery cell is bent at 90°, and the bent current collector is directly welded and fixed to the base plate of the irregularly shaped electrode tab.

[0016] According to a preparation method provided by the present invention, the step of sealing the outer edge of the tab to the soft packaging material by hot pressing specifically includes:

[0017] The outer edge of the electrode tab and the soft packaging material are heat-pressed together using a segmented end cap.

[0018] According to a preparation method provided by the present invention, the step of using a segmented end cap to perform heat-press encapsulation of the outer edge of the electrode tab and the flexible packaging material specifically includes:

[0019] The flexible packaging material and the planar area of ​​the outer edge of the electrode tab are encapsulated by hot pressing with a straight end cap;

[0020] The corner area of ​​the soft packaging material and the outer edge of the tab is sealed by hot pressing with a corner end cap.

[0021] According to a preparation method provided by the present invention, after sealing the tab to the flexible packaging material by hot pressing, the method further includes:

[0022] Top sealing operations are performed on the positive and negative sides of the battery cell, and the positive and negative terminals of the air bag are sealed respectively.

[0023] Electrolyte is injected into the battery cell, and the side of the gas bag is sealed after the injection is completed; the battery cell is subjected to formation treatment, and after the formation of the battery cell is completed, the gas is vented and sealed again.

[0024] According to a preparation method provided by the present invention, after the cell formation is completed and the degassing and secondary sealing are performed, the method further includes:

[0025] Fold the outer edge of the tab away from the base plate inward to form a folded edge.

[0026] The present invention provides an irregularly shaped electrode tab, a pouch battery, an electric vehicle, and a method for manufacturing a pouch battery. The pouch battery includes a base plate and an outer edge of the electrode tab arranged around the base plate. The base plate is used to connect the terminals of the battery cell, so that the current of the battery cell is transmitted outward through the outer edge of the electrode tab, thereby increasing the width and cross-sectional area of ​​the battery cell's electrode tab and improving the battery's overcurrent capacity. The outer edge of the electrode tab is connected to the base plate to form a three-dimensional structure. During packaging, the outer edge of the electrode tab is roughly flush with the outer wall of the battery cell, so that the thickness of the pouch battery is not limited by the depth of the dent in the pouch material, which helps to increase the capacity of the pouch battery. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram of the irregularly shaped electrode provided by the present invention;

[0029] Figure 2 This is one of the packaging schematic diagrams of the battery cell and irregularly shaped electrode provided by the present invention;

[0030] Figure 3 This is the second schematic diagram of the packaging of the battery cell and the irregularly shaped electrode provided by the present invention;

[0031] Figure 4 This is a schematic diagram of the structure of the soft-pack battery after side sealing pre-sealing according to an embodiment of the present invention;

[0032] Figure 5 This is a schematic diagram of the structure of the soft-pack battery after top sealing according to an embodiment of the present invention;

[0033] Figure 6 This is a schematic diagram of the long side of the outer edge of the electrode tab and the soft packaging material in the irregular electrode tab provided in the embodiment of the present invention;

[0034] Figure 7 This is a schematic diagram of the encapsulation of the short side of the outer edge of the irregularly shaped electrode tab and the soft packaging material in an embodiment of the present invention;

[0035] Figure 8 This is a schematic diagram of the corner of the outer edge of the irregularly shaped electrode tab and the packaging material of the soft packaging material provided in the embodiment of the present invention;

[0036] Figure 9 This is a schematic diagram of the structure of the soft-pack battery after vacuuming and double sealing according to an embodiment of the present invention;

[0037] Figure 10This is a schematic diagram of the structure of the soft-pack battery after folding, as provided in an embodiment of the present invention.

[0038] Figure label:

[0039] 200. Irregularly shaped tab; 211. Outer edge of tab; 212. Base plate; 213. Tab adhesive; 100. Battery cell; 111. Current collector; 300. Aluminum-plastic film; 301. Air bag; 311. Positive electrode side seal pre-sealing edge; 312. Negative electrode side seal pre-sealing edge; 321. Positive electrode top seal edge; 322. Negative electrode top seal edge; 331. Positive electrode air bag seal edge; 332. Negative electrode air bag seal edge; 340. Vacuum double seal edge; 341. Sealing fold edge; 400. Flexible connecting piece; 501. Outer end cap; 502. Inner end cap; 503. Corner outer end cap; 504. Corner inner end cap. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0041] The following is combined with Figure 1 The irregularly shaped electrode tab of the present invention is described.

[0042] Figure 1 This is a perspective view of the irregularly shaped electrode tab provided by the present invention. For example... Figure 1 As shown, the irregularly shaped tab 200 includes a base plate 212 and an outer edge 211 of the tab. One end of the outer edge 211 of the tab is connected to the outer edge of the base plate 212. The outer edge 211 of the tab is arranged around the circumference of the base plate 212. The base plate 212 is used to weld and fix to the electrode of the battery cell 100.

[0043] The base plate 212 is a square flat plate, and the outer edge 211 of the electrode tab is arranged around the circumference of the base plate 212. The shape of the base plate 212 is consistent with the end face shape of the battery cell 100; the outer edge 211 of the electrode tab is perpendicular to the base plate 212, serving as the circumferential edge of the base plate 212 for sealing connection with the soft packaging material. Specifically, the base plate 212 and the outer edge 211 of the electrode tab are made of the same material. During packaging, the terminals of the battery cell 100 are welded and fixed to the base plate 212. The base plate 212 leads the electrical energy of the battery cell 100 to the outer edge 211 of the electrode tab, and transmits it outward through the outer edge 211. The base plate 212 acts as a relay to lead the current to the outer edge 211 of the electrode tab; the outer edge 211 of the electrode tab performs the conductive function of a traditional electrode tab, leading the current out to form a circuit, and is then sealed and connected to the aluminum-plastic film.

[0044] The positive and negative terminals of the battery cell 100 are located at different ends of the cell body. The size of the base plate 212 is approximately the same as the end face size of the battery cell 100, and the base plate 212 seals the terminals of the battery cell 100. During assembly, a shaped tab 200 is provided at each of the positive and negative terminals of the battery cell 100, with one shaped tab 200 serving as the positive tab and the other as the negative tab. The base plate 212 in the positive tab is connected to the positive terminal of the battery cell 100, and the base plate 212 in the negative tab is connected to the negative terminal of the battery cell 100. Thus, the base plate 212 enables the internal and external connection of the pouch battery, allowing the current of the battery cell to be transmitted outward through the outer edge 211 of the tab. The outer edge 211 of the tab is larger than the thin sheet-like tab of a traditional pouch battery, which can multiply the tab cross-sectional area of ​​the pouch battery and greatly improve the overcurrent capacity of the pouch battery.

[0045] In this embodiment, the electrode terminals of the battery cell 100 are fitted with irregularly shaped tabs 200. A soft-pack material, such as an aluminum-plastic film 300, wraps around the circumference of the battery cell 100, ensuring that the aluminum-plastic film 300 is substantially in contact with the outer edge 211 of the tab. This means the thickness difference of the aluminum-plastic film 300 from the battery cell 100 to the tab encapsulation area is minimal, eliminating the need for punching indentations in the aluminum-plastic film 300. Compared to traditional encapsulation processes that require punching indentations in the aluminum-plastic film 300, the thickness of the soft-pack battery provided by this invention is not limited by the depth of the punching indentation in the aluminum-plastic film 300, effectively increasing the upper capacity limit and volumetric energy density of the soft-pack battery. Furthermore, the close contact between the aluminum-plastic film 300 and the outer edge 211 of the tab facilitates encapsulation. Compared to traditional thin-sheet tab structures, the tab encapsulation area is less prone to wrinkles, effectively improving the effectiveness and reliability of the encapsulation.

[0046] Traditional tabs are flat, thin sheet structures. The irregularly shaped tab 200 provided in this embodiment of the invention is a three-dimensional spatial structure. After the irregularly shaped tab 200 is fixed to the end of the cell 100, it is used in conjunction with soft packaging material to complete the encapsulation of the cell 100, thereby improving the upper limit of the capacity and the volumetric energy density of the cell 100.

[0047] The irregularly shaped tab 200 provided in this embodiment of the invention includes a base plate 212 and an outer edge 211 of the tab surrounding the base plate 212. The base plate 212 is used to connect the terminals of the battery cell 100. The outer edge 211 of the tab transmits the current of the battery cell 100 outward. By increasing the width and cross-sectional area of ​​the tab, the overcurrent capacity of the battery is improved. The outer edge 211 of the tab is connected to the base plate 212 to form a three-dimensional structure. During packaging, the outer edge 211 of the tab is roughly flush with the outer wall of the battery cell 100. There is no thickness difference in the soft-pack material from the battery cell 100 to the tab packaging area, so that the thickness of the soft-pack battery is not limited by the depth of the soft-pack material, which helps to improve the capacity of the soft-pack battery.

[0048] The outer side of the tab 211 is provided with tab adhesive 213. The base plate 212 and the outer edge of the tab 211 are connected to form a box structure. The outer side of the tab 211 refers to the side of the tab 211 facing the outside of the box structure.

[0049] The tab adhesive 213 covers the outer side of the tab outer edge 211 or only a portion of the tab outer edge 211. For example, the tab adhesive 213 is only applied to the area near the base plate 212 on the outer side of the tab outer edge 211. The coverage area of ​​the tab adhesive 213 is determined according to the requirements of the flexible packaging material and the heat-pressed encapsulation width of the tab outer edge 211.

[0050] Optionally, the tab adhesive 213 can be any of white adhesive, black adhesive, yellow adhesive, or a single-layer adhesive. White adhesive is made by co-extrusion of three layers of polypropylene material with different functions. The heat-sealing temperature of the functional layer of white adhesive is 150°C–180°C, a relatively wide range, slightly lower than the battery's encapsulation temperature of 180°C–220°C, effectively preventing cross-sectional short circuits and increasing the operable temperature range during encapsulation. Yellow adhesive has a functional layer with a melting point close to 300°C, making heat sealing easier. The middle functional layer is a non-woven fiber layer, resulting in better interface fusion. The appropriate type of tab adhesive 213 should be selected based on factors such as the adhesion between the tab adhesive 213 and the soft-pack material, the tightness of edge sealing, and the sealing process.

[0051] During encapsulation, the soft packaging material and the tab adhesive 213 on the outer edge 211 of the tab melt together under hot pressing or hot fusion process to achieve a sealing effect and realize a sealed adhesive connection.

[0052] In an optional embodiment, the base plate 212 is provided with a groove, the recess direction of which is consistent with the extension direction of the outer edge 211 of the tab.

[0053] The groove is located in the middle of the base plate 212 and is recessed outward. That is, when the base plate 212 is connected to the electrode of the battery cell 100, the groove opening faces the battery cell 100. As a result, the base plate 212 has an outwardly protruding non-planar structure, so that the electrode welding area of ​​the battery cell 100 and the outer edge 211 of the electrode overlap in height, thereby further improving the space utilization rate of the battery cell 100.

[0054] The depth of the groove is designed based on the performance specifications of the pouch battery. The shape of the groove can be square, elliptical, or other geometric shapes.

[0055] The irregularly shaped tab 200 provided in this embodiment of the invention further improves the volume utilization rate of the battery cell 100 by providing an outwardly recessed groove on the base plate 212.

[0056] In one optional embodiment, the outer edge 211 of the electrode tab and the base plate 212 are integrally formed. Specifically, the circumferential edge of the base plate 212 is bent to one side to form the annular outer edge 211 of the electrode tab, which is simple to manufacture and easy to produce. In yet another optional embodiment, the outer edge 211 of the electrode tab and the base plate 212 are welded together. Specifically, the outer edge 211 of the electrode tab and the base plate 212 are separate structures, with one end of the outer edge 211 fixed to the edge of the base plate 212 by laser welding.

[0057] The following is combined with Figure 2 and Figure 3 The present invention describes a pouch cell battery.

[0058] This invention also provides a pouch battery, which includes a cell 100 and irregularly shaped tabs 200 as described above.

[0059] Among them, cell 100 has the same cell structure as traditional soft-pack batteries, and the soft-pack battery adopts the following... Figure 1 The irregularly shaped electrode 200 is shown. Figure 2 and Figure 3 These are schematic diagrams illustrating two possible combinations of the battery cell 100 and the irregularly shaped electrode tab 200 provided in this embodiment of the invention. Figure 2 and Figure 3 As shown, a positive terminal is reserved at the top of the battery cell 100, and a negative terminal is reserved at the bottom of the battery cell 100. One irregularly shaped tab 200 serves as the positive tab and is installed at the positive terminal of the battery cell 100; another irregularly shaped tab 200 serves as the negative tab and is installed at the negative terminal of the battery cell 100. Optionally, as... Figure 2 As shown, the base plate 212 of the positive electrode tab is directly connected to the positive terminal, and the base plate 212 of the negative electrode tab is directly connected to the negative terminal. Alternatively, as... Figure 3 As shown, the base plate 212 of the positive electrode tab is connected to the positive electrode connection terminal via a flexible connecting piece 400, and the base plate 212 of the negative electrode tab is connected to the negative electrode connection terminal via another flexible connecting piece 400. The outer edge 211 of the positive electrode tab is heat-pressed with the aluminum-plastic film 300 to form a positive electrode side sealing pre-sealing edge 311, and the outer edge 211 of the negative electrode tab is heat-pressed with the aluminum-plastic film 300 to form a negative electrode side sealing pre-sealing edge 312.

[0060] Understandably, if the positive and negative terminals of the cell 100 in a pouch battery are located on the same end, then two irregularly shaped tabs 200 are provided on the same side of the cell 100, and the two irregularly shaped tabs 200 are separated by an insulating material. The specific connection process is similar to that above and will not be described again.

[0061] Compared to traditional soft-pack batteries packaged with aluminum-plastic film 300, the electrode of the cell 100 in this soft-pack battery is packaged with irregularly shaped tabs 200, and the circumferential direction of the cell 100 is packaged with aluminum-plastic film 300. This overcomes the problem that the thickness of traditional soft-pack batteries is limited by the depth of the perforation of aluminum-plastic film 300, and improves the current carrying capacity of the soft-pack battery by using the larger width and cross-sectional area of ​​the outer edge 211 of the tabs.

[0062] This invention also provides an electric vehicle that includes a pouch battery as described above.

[0063] Electric vehicles include electric cars, electric buses, and other electric vehicles, encompassing both pure electric vehicles powered solely by electricity and hybrid electric vehicles powered by a combination of electricity and gasoline. Electric vehicles utilize pouch batteries, as described above, to extend their operating time.

[0064] The following is combined with Figures 2-10 The method for preparing the pouch cell of the present invention is described.

[0065] This invention also provides a method for preparing the soft-pack battery as described above, which includes the following steps:

[0066] Step S10: Weld the positive and negative terminals of the battery cell 100 to the base plate 212 of a shaped tab 200 respectively.

[0067] Step S20: Use soft packaging material to cover the battery cell 100 and the irregularly shaped tab 200, and leave an air bag 301; pre-seal the soft packaging material at both ends near the battery cell 100.

[0068] Step S30: The outer edge 211 of the tab is sealed and connected to the soft packaging material by hot pressing.

[0069] Specifically, such as Figure 2 As shown, one end of the battery cell 100 is the positive terminal, and the other end is the negative terminal. The negative terminal current collector is connected to the base plate 212 of a shaped tab 200, which serves as the negative terminal lead. Similarly, the positive terminal current collector is connected to the base plate 212 of another shaped tab 200, which serves as the positive terminal lead. Alternatively, the positive and negative terminals of the battery cell 100 can be located at the same end, in which case two shaped tabs 200 can be used. Since the outer edge 211 of the tab is connected to the battery cell's terminals through the base plate 212, it can transmit current outward, performing the conductive function of a traditional tab. The width and cross-sectional area of ​​the outer edge 211 of the tab are larger than those of a traditional thin-film tab, which can support larger charging and discharging currents, effectively improving the overcurrent capacity of the pouch battery.

[0070] The packaging of cells 100 with the positive and negative terminals on the same side and the packaging of cells 100 with the positive and negative terminals on opposite sides are similar. The following describes the manufacturing method of pouch cells using the packaging process with the positive and negative terminals on opposite sides of cells 100 as an example.

[0071] Flexible packaging materials, such as aluminum-plastic film 300, are wrapped around the outside of the battery cell 100 and the irregularly shaped tabs 200, with an air bag 301 reserved on one side of the battery cell 100. The flexible packaging materials are pre-sealed at both ends near the battery cell 100. Figure 4 This is a schematic diagram of the structure of a soft-pack battery after side sealing pre-sealing, as provided in an embodiment of the present invention. Figure 4 As shown, after side sealing, a positive side sealing pre-sealing edge 311 and a negative side sealing pre-sealing edge 312 are formed on the side of the positive and negative terminals of the soft-pack material closest to the cell 100. The positive and negative side sealing pre-sealing edges 311 and 312 are used to bond the soft-pack material to the outer surface of the tab outer edge 211 of the irregularly shaped tab 200. Tab adhesive 213 is provided on the outer surface of the tab outer edge 211, facilitating hot-pressing for fusion sealing after the soft-pack material is bonded to the outer surface of the tab outer edge 211 of the irregularly shaped tab 200. During hot-pressing, the functional layer in the tab adhesive 213 melts and bonds with the encapsulation layer in the soft-pack material, such as the aluminum-plastic film 300, to form an effective encapsulation structure, achieving tab encapsulation. The encapsulation layer of the aluminum-plastic film 300 refers to the innermost layer of the aluminum-plastic film 300.

[0072] The pouch battery manufacturing method provided in this embodiment of the invention, compared with the traditional pouch battery manufacturing method, first installs irregularly shaped tabs 200 at opposite ends of the cell 100, and then covers the cell 100 with pouch material along the circumference, so that the circumference of the cell 100 is covered by the pouch material and the ends of the cell 100 are sealed by the irregularly shaped tabs 200. In this way, the cell 100 is sealed by the pouch material and the irregularly shaped tabs 200, thereby improving the volume utilization rate of the cell 100 and thus improving the capacity and volumetric energy density of the pouch battery.

[0073] Step S10, which involves welding and fixing the positive and negative terminals of the battery cell 100 to the base plate of the irregularly shaped electrode tab 200, specifically includes:

[0074] In an optional embodiment, step S11 involves bending the current collector 111 of the battery cell 100 by 90°. Step S12 involves welding the bent current collector 111 to the flexible connecting piece 400. Step S13 involves welding the flexible connecting piece 400 to the base plate 212 of the irregularly shaped electrode tab 200.

[0075] like Figure 2As shown, when installing the irregularly shaped tab 200 at the negative terminal of the battery cell 100, the negative current collector of the battery cell 100 is bent at 90°, and then the flexible connecting piece 400 is welded to the welding end of the negative current collector. Then, the flexible connecting piece 400 is welded to the base plate 212 of the irregularly shaped tab 200. The method of installing the irregularly shaped tab 200 at the positive terminal of the battery cell 100 is similar to that at the negative terminal and will not be described again. During the packaging process, the irregularly shaped tab 200 can be installed at either the positive or negative terminal of the battery cell 100 first, and then another irregularly shaped tab 200 can be installed at the other end; alternatively, the irregularly shaped tabs 200 can be installed simultaneously at both ends of the battery cell 100. Specifically, the welding ends of the flexible connecting piece 400 and the current collector 111 are connected by ultrasonic welding, and the connection between the flexible connecting piece 400 and the irregularly shaped tab 200 is achieved by laser welding, which reduces welding deformation, increases welding speed, and improves welding effect.

[0076] In yet another alternative embodiment, such as Figure 3 As shown, in step S11, the current collector 111 of the battery cell 100 is bent at 90°. In step S12, the bent current collector 111 is directly welded and fixed to the base plate 212 of the irregular electrode tab 200.

[0077] The current collector 111 is bent at 90° to reduce space occupation and help improve the energy density of the battery. The bent current collector 111 can be directly welded to the base plate 212. Compared with the method of connecting through the soft connecting piece 400, there are fewer welding steps and the assembly efficiency is higher.

[0078] The method for preparing a soft-pack battery provided in this embodiment of the invention involves welding irregularly shaped tabs 200 to both ends of the cell 100. During welding, the current collector 111 is bent at 90° before welding, which avoids the waste of welding space caused by the straight tabs during conventional soft-pack battery packaging, improves the energy density of the battery, and improves the current carrying capacity of the soft-pack battery by using the outer edge 211 of the tabs for current conduction.

[0079] In an optional embodiment, step S30, sealing the tab outer edge 211 to the soft packaging material by hot pressing, specifically includes: using a segmented end cap to hot press and encapsulate the tab outer edge 211 and the soft packaging material.

[0080] like Figure 1 As shown, the outer edge 211 of the tab is a square ring with a smooth, curved corner. During encapsulation, an inner cap 502 is provided on the inner side of the soft packaging material and the outer edge 211 of the tab, and an outer cap 501 is provided on the outer side of the soft packaging material and the outer edge 211 of the tab. The inner cap 502 and the outer cap 501 are positioned opposite each other and move synchronously to the opposite sides of the outer edge 211 of the tab and the soft packaging material to heat seal them.

[0081] To create an effective seal at the corner of the tab's outer edge 211, this embodiment of the invention employs a segmented end cap to seal different areas of the soft-pack material and the tab's outer edge 211. Specifically, as shown... Figure 6 and Figure 7 As shown, both the long and short sides of the outer edge 211 of the tab are encapsulated with straight end caps and flexible packaging material via heat pressing. Figure 8 As shown, the corner of the outer edge 211 of the electrode is sealed with a corner cap and a soft-pack material by heat pressing. Specifically, as... Figure 8 As shown, an inner corner end cap 504 is provided at the corner of the outer edge 211 of the electrode tab and on the inner side of the soft packaging material, and an outer corner end cap 503 is provided at the corner of the outer edge 211 of the electrode tab and on the outer side of the soft packaging material. The inner corner end cap 504 and the outer corner end cap 503 cooperate with each other to heat-press seal each corner of the outer edge 211 of the electrode tab and the soft packaging material.

[0082] To improve thermoforming efficiency, straight end caps are available in two specifications. One type of straight end cap is longer, such as... Figure 6 As shown, the dimensions of the straight end cap of this specification are consistent with the long side dimension of the outer edge 211 of the tab. The long side of the outer edge 211 of the tab and the soft packaging material can be sealed by a single hot pressing using inner and outer straight end caps. For example... Figure 7 As shown, the dimensions of another specification of straight end cap are equivalent to the short side of the outer edge 211 of the tab. The inner and outer straight end caps are heat-pressed together to encapsulate the soft packaging material and the short side of the outer edge 211 of the tab.

[0083] Understandably, other types of end caps can also be used to seal the soft packaging material and the long or short side of the outer edge 211 of the tab. For example, a straight end cap may only have one specification, the size of which is equivalent to the size of the short side of the outer edge 211 of the tab. The short side of the outer edge 211 of the tab and the soft packaging material can be heat-sealed in one step, and the long side of the outer edge 211 of the tab and the soft packaging material are sealed using this straight end cap in a splicing manner. Specifically, the long side of the outer edge 211 of the tab and the soft packaging material are conveyed forward. When they reach the heating position, the inner end cap 502 and the outer end cap 501 move simultaneously to the opposite sides of the long side of the outer edge 211 of the tab and the soft packaging material and heat-seal them. After the inner cap 502 and the outer cap 501 leave the long side of the outer edge 211 of the tab and the surface of the soft packaging material, the outer edge 211 of the tab and the soft packaging material continue to move forward, so that the next encapsulation part moves to the heating position. The inner cap 502 and the outer cap 501 move again to the opposite sides of the long edge 211 of the tab and the soft packaging material and heat seal them. This cycle is repeated, and each encapsulation part is spliced ​​to form a continuous encapsulation area until the long edge of the outer edge 211 of the tab and the soft packaging material are intermittently encapsulated.

[0084] In addition, the inner end cap 502 and outer end cap 501 of the segmented heat-sealing system can both be cylindrical end caps. The outer edge 211 of the tab and the flexible packaging material are located between the two cylindrical end caps. The dimensions of the cylindrical end caps are consistent with the dimensions at the corner of the outer edge 211 of the tab. During the forward movement of the outer edge 211 of the tab and the flexible packaging material, the two cylindrical end caps heat-seal the outer edge 211 of the tab and the flexible packaging material. Since the forward movement of the outer edge 211 of the tab and the flexible packaging material is continuous and uninterrupted, the cylindrical end caps can achieve continuous sealing, greatly improving production efficiency and preventing misalignment between the outer edge 211 of the tab and the flexible packaging material.

[0085] Figure 8 This is a schematic diagram of the structure of the soft-pack battery provided in an embodiment of the present invention after it is encapsulated along the outer edge of the tab. Specifically,

[0086] Based on any of the above embodiments, step S30, after sealing the outer edge 211 of the electrode tab to the soft packaging material by hot pressing, further includes:

[0087] Step S40: Perform top sealing operations on the positive and negative sides of the cell 100 respectively, and seal the positive and negative terminals of the air bag 301 respectively.

[0088] Step S50: Inject electrolyte into cell 100, and seal the side of gas bag 301 after the electrolyte injection is completed; perform formation treatment on cell 100, and perform exhaust and resealing after the formation of cell 100 is completed.

[0089] Specifically, after hot pressing to seal the outer edge 211 of the electrode tab and the soft packaging material, top sealing operations are performed on the positive and negative sides of the cell 100 respectively. Figure 5 This is a schematic diagram of the structure of the soft-pack battery provided in an embodiment of the present invention after top sealing. Figure 5 As shown, a positive top seal edge 321 is formed on the positive electrode side of the battery cell 100, and a negative top seal edge 322 is formed on the negative electrode side. Then, the positive and negative terminals of the gas bag 301 are sealed, forming a positive gas bag seal edge 331 and a negative gas bag seal edge 332, respectively. The positive terminal of the gas bag 301 is the end of the gas bag 301 on the same side as the positive electrode side of the battery cell 100, and the negative terminal of the gas bag 301 is the end on the same side as the negative electrode side of the battery cell 100. After the top sealing operation and the sealing operations of the positive and negative terminals of the gas bag 301, only the side of the gas bag 301 away from the battery cell 100 remains open, through which electrolyte is injected into the battery cell 100. After the electrolyte injection is completed, the sidewall of the gas bag 301 is sealed, completely isolating the inside of the battery cell 100 from the external environment. Then, the cell 100 is allowed to stand, with high-temperature or room-temperature standing depending on the manufacturing process, to ensure that the injected electrolyte fully wets the electrode plates. After standing, the cell 100 undergoes formation treatment.

[0090] During the formation process, the battery cell 100 undergoes its first charge. The electrode material and electrolyte react at the solid-liquid interface, forming a passivation layer covering the electrode material surface. This passivation layer exhibits the characteristics of a solid electrolyte and is called a solid electrolyte interface (SEI) film. The SEI film is insoluble in organic solvents and can exist stably in organic electrolyte solutions. Solvent molecules can pass through this passivation layer, effectively preventing the co-intercalation of solvent molecules and avoiding damage to the electrode material caused by solvent molecule co-intercalation. This significantly improves the cycle performance and lifespan of the electrode. Since the battery cell 100 may deform after formation, a shaping process can be added after formation.

[0091] It should be noted that after pre-sealing and top sealing are completed, the sealing quality needs to be checked with a testing device to prevent defective products from flowing to the next stage.

[0092] Since gas is generated during the formation process, it needs to be extracted before the second sealing. Specifically, the gas bag 301 is punctured using a guillotine or similar tool, and a vacuum is simultaneously drawn to expel the gas from the gas bag 301. Then, the gas bag 301 is sealed on the side closest to the battery cell 100. Figure 9 This is a schematic diagram of the structure of the soft-pack battery provided in an embodiment of the present invention after vacuuming and double-sealing. Figure 9 As shown, after the gas bag 301 is sealed twice, a vacuum-sealed edge 340 is formed, completing the encapsulation of the entire battery cell 100. The second sealing operation is performed immediately after the gas is extracted to ensure the airtightness of the battery cell 100. Optionally, a segmented vacuuming method can be used during the vacuuming process. The gas bag 301 is divided into several segments, and the vacuum is slowly evacuated to the set vacuum level. Compared with the method of evacuating all the way through, the vacuuming speed is reduced, avoiding the extraction of too much electrolyte and reducing the defect rate of the battery cell 100 in the vacuum-sealing stage. After the second sealing is completed, the gas bag 301 is cut off. The vacuum-sealed edge 340 is then folded. Figure 10 This is a schematic diagram of the structure of the soft-pack battery provided in an embodiment of the present invention after folding. Figure 10 As shown, after folding, a sealing fold 341 is formed. This sealing fold 341 is close to the battery cell 100 to ensure that the width of the battery cell 100 does not exceed the standard.

[0093] After being folded, the battery cell 100 undergoes capacity grading in a capacity grading cabinet to test whether its capacity reaches the specified minimum value. After the capacity grading test, any cells 100 that fail the capacity test are discarded to prevent them from entering the next stage of production. Cells 100 that pass the capacity test will proceed to subsequent processes, such as appearance inspection, application of adhesive tape, and edge voltage testing. The specific steps may be added or removed depending on the manufacturing requirements of the pouch battery.

[0094] In an optional embodiment, step S50 further includes folding the end of the tab outer edge 211 away from the base plate 212 inward to form a folded edge.

[0095] Specifically, the outer edge 211 of the electrode is provided with electrode adhesive 213 only in the area near the base plate 212, and the area of ​​the outer edge 211 of the electrode without electrode adhesive 213 is folded inward to form a folded edge.

[0096] Optionally, the outer edge 211 of the electrode tab is a square ring. The area on the short side of the outer edge 211 where the electrode tab adhesive 213 is not provided is cut off, and the area on the long side of the outer edge 211 where the electrode tab adhesive 213 is not provided is folded inward to form a folded edge, thereby reducing the space occupied by the outer edge 211 of the electrode tab. Alternatively, the corner of the outer edge 211 of the electrode tab is cut longitudinally, and both the short and long sides of the outer edge 211 of the electrode tab are folded inward to form folded edges.

[0097] By folding the outer edge 211 of the tab inward, the space utilization rate of the cell 100 in the length direction is improved, thereby increasing the capacity and energy density of the pouch battery.

[0098] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An irregularly shaped electrode, characterized in that, It includes a base plate and an outer edge of a tab. One end of the outer edge of the tab is connected to the outer edge of the base plate. The outer edge of the tab is arranged circumferentially around the base plate. The base plate is used to weld and fix to the electrode of the battery cell.

2. The irregularly shaped electrode tab according to claim 1, characterized in that, The outer edge of the electrode tab is provided with electrode tab adhesive.

3. The irregularly shaped electrode tab according to claim 1, characterized in that, The base plate is provided with a groove, and the recessed direction of the groove is consistent with the extension direction of the outer edge of the electrode tab.

4. The irregularly shaped electrode tab according to claim 1, characterized in that, The base plate and the outer edge of the electrode tab are an integral structure.

5. A pouch battery, characterized in that, It includes a battery cell and a shaped electrode tab as described in any one of claims 1 to 4, wherein the base plate is welded and fixed to the electrode ends of the battery cell.

6. An electric vehicle, characterized in that, Includes the pouch cell battery as described in claim 5.

7. A method for preparing a soft-pack battery as described in claim 5, characterized in that, include: The positive and negative terminals of the battery cell are welded and fixed to the base plate of a non-standard electrode tab; The battery cell and the irregularly shaped electrode tabs are covered with soft packaging material, with air pockets provided. The soft-pack material is pre-sealed at both ends near the battery cell; The outer edge of the tab is sealed to the soft packaging material by hot pressing.

8. The preparation method according to claim 7, characterized in that, The specific steps of welding and fixing the positive and negative terminals of the battery cell to the base plate of the irregularly shaped electrode tab include: The current collector of the battery cell is bent at 90°, and the bent current collector is directly welded and fixed to the base plate of the irregularly shaped electrode tab.

9. The preparation method according to claim 7, characterized in that, The process of sealing the outer edge of the electrode tab to the soft packaging material by hot pressing specifically includes: The outer edge of the electrode tab and the soft packaging material are heat-pressed together using a segmented end cap.

10. The preparation method according to claim 9, characterized in that, The process of using a segmented end cap to perform heat-press sealing of the outer edge of the electrode tab and the flexible packaging material specifically includes: The flexible packaging material and the planar area of ​​the outer edge of the electrode tab are encapsulated by hot pressing with a straight end cap; The corner area of ​​the soft packaging material and the outer edge of the tab is sealed by hot pressing with a corner end cap.

11. The preparation method according to any one of claims 8 to 10, characterized in that, After sealing the electrode tab to the soft packaging material by hot pressing, the process further includes: Top sealing operations are performed on the positive and negative sides of the battery cell, and the positive and negative terminals of the air bag are sealed respectively. Electrolyte is injected into the battery cell, and the side of the gas bag is sealed after the injection is completed; the battery cell is subjected to formation treatment, and after the formation of the battery cell is completed, the gas is vented and sealed again.

12. The preparation method according to claim 11, characterized in that, After the cell formation process is completed and the secondary sealing is performed, the process also includes: Fold the outer edge of the tab away from the base plate inward to form a folded edge.

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