Battery cell structure, battery and manufacturing method of battery cell structure

Abstract

This disclosure provides a cell structure, a battery, and a method for manufacturing the cell structure, relating to the field of battery technology. A cell structure includes: an outer packaging structure and a wound bare cell encapsulated within the outer packaging structure. The wound bare cell is formed by sequentially connecting at least two winding units along a winding direction. Each winding unit includes a positive electrode, a negative electrode, and a separator disposed between them. The lengths of the positive and negative electrodes in adjacent winding units may be the same or different, or the number of positive and negative electrodes in adjacent winding units may be the same or different.

Description

Technical Field

[0001] This disclosure relates to the field of battery technology, and in particular to a cell structure, a battery, and a method for manufacturing the cell structure. Background Technology

[0002] In portable electronic devices such as laptops and tablets, batteries typically consist of multiple small-capacity cells to meet the voltage and capacity requirements of these devices. However, with the pursuit of higher battery energy density and cost control, using "large-capacity, fewer-number" cells to build batteries has become a cost-effective design trend. However, when the number of battery cells decreases, the cell undervoltage (CUV) of a single cell increases. In low-charge (low SOC) and instantaneous high-power scenarios (such as running high-power software or multitasking), the voltage of a single cell can easily be pulled below the CUV, triggering the circuit's protection mechanism and causing the electronic device to shut down unexpectedly, severely impacting the user experience. Summary of the Invention

[0003] This disclosure provides a cell structure, a battery, and a method for manufacturing the cell structure.

[0004] According to a first aspect of this disclosure, a battery cell structure is provided, including an outer packaging structure and a wound bare battery cell encapsulated within the outer packaging structure, wherein the wound bare battery cell is formed by sequentially connecting at least two winding units along a winding direction.

[0005] The winding unit includes a positive electrode sheet, a negative electrode sheet, and a diaphragm disposed between the two. The lengths of the positive and negative electrode sheets in adjacent winding units are the same or different, or the number of positive and negative electrode sheets in adjacent winding units is the same or different.

[0006] In one possible implementation, the positive and negative electrode plates in adjacent winding units are of the same length, so that the current-carrying capacity of each winding unit in series is consistent; and / or, The spacing between the electrodes of adjacent winding units ranges from the width of the first layer to the width of the fourth layer of the wound bare cell.

[0007] In one embodiment, the wound bare cell is formed by connecting the positive electrode tabs of each winding unit to the negative electrode tabs of adjacent winding units in series to form a series structure within the wound bare cell. The positive or negative tab of the innermost winding unit and the negative or positive tab of the outermost winding unit of the wound bare cell are respectively led out to the outside of the outer packaging structure as the positive and negative tabs of the cell structure.

[0008] In one possible embodiment, the positive and negative electrode tabs are respectively disposed at the midpoint of the positive and negative electrode plates in the length direction of each winding unit; and / or, After the wound bare cell is encapsulated into the outer packaging structure, the tabs that are connected in series are folded to the top seal of the outer packaging structure.

[0009] In one possible implementation, the number of positive and / or negative electrode plates in adjacent winding units is different; The same winding unit includes at least two positive electrode plates or at least two negative electrode plates, and the positive electrode plates or negative electrode plates are connected to each other by electrode tabs. And / or, Different electrodes within the same winding unit may have different specifications or electrochemical properties.

[0010] In one embodiment, the number of winding units in the wound bare cell is 2 to 10, and the number of winding units is determined based on the ratio between the total battery capacity and the capacity of the original cell replaced by the cell structure, and the ratio between the total battery capacity and the capacity of the cell structure.

[0011] According to a second aspect of this disclosure, a battery is provided, comprising: The encapsulation housing has a receiving cavity filled with a high-voltage electrolyte. The battery cell structure disposed within the receiving cavity includes an outer packaging structure and a wound bare battery cell encapsulated within the outer packaging structure. The wound bare battery cell is formed by at least two winding units sequentially connected along the winding direction. The winding unit includes a positive electrode sheet, a negative electrode sheet, and a diaphragm disposed between the two. The lengths of the positive and negative electrode sheets in adjacent winding units are the same or different, or the number of positive and negative electrode sheets in adjacent winding units is the same or different.

[0012] In one embodiment, the high-voltage electrolyte includes a lithium salt, an organic solvent, and functional additives; The lithium salt in the high-voltage electrolyte has a mass percentage content of 7% to 15%. The organic solvent in the high-voltage electrolyte has a mass percentage content of 70% to 90%. The functional additive has a mass percentage content of 3% to 15% in the high-voltage electrolyte.

[0013] In one embodiment, the lithium salt is lithium hexafluorophosphate; The organic solvent is a mixture of ethylene carbonate, propylene carbonate, diethyl carbonate and a high-voltage solvent, with a mass ratio of 1:1:2:(1~10). The high-voltage solvent is a combination of at least two of sulfolane, dimethyl sulfone, n-butyl sulfone, diethyl sulfone, sulfone phenyl sulfone, methyl ethyl sulfone, methyl methoxy sulfone and methyl ethoxy sulfone. The functional additive is at least one of sulfone solvents, nitrile solvents and their ether derivatives.

[0014] According to a third aspect of this disclosure, a method for manufacturing a battery cell structure is provided, comprising: A wound bare cell is formed by sequentially connecting and winding at least two winding units along the winding direction; the winding unit includes a positive electrode, a negative electrode, and a diaphragm disposed between the two; the lengths of the positive and negative electrodes in adjacent winding units are the same or different, or the number of positive and negative electrodes in adjacent winding units is the same or different. The positive electrode tabs of each winding unit in the wound bare cell are connected in series with the negative electrode tabs of the adjacent winding unit to form a series structure within the wound bare cell. The wound bare cell is packaged into an outer packaging structure, and the series-welded tabs are folded to the top seal of the outer packaging structure. The positive or negative tab of the innermost winding unit that is not series-welded and the negative or positive tab of the outermost winding unit are led out to the outside of the outer packaging structure.

[0015] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of this disclosure, nor is it intended to limit the scope of this disclosure. Other features of this disclosure will become readily apparent from the following description. Attached Figure Description

[0016] The above and other objects, features, and advantages of this disclosure will become readily apparent from the following detailed description of exemplary embodiments, taken in conjunction with the accompanying drawings. Several embodiments of this disclosure are illustrated in the drawings by way of example and not limitation, in which: In the accompanying drawings, the same or corresponding reference numerals indicate the same or corresponding parts.

[0017] Figure 1 This diagram illustrates the structure of a high-capacity battery cell with 2 cells in 1 pack in the prior art. Figure 2 This diagram illustrates the structure of a conventional 3-cell-in-1-pack battery cell in the prior art. Figure 3 A schematic diagram of the structure of a winding unit in the prior art is shown; Figure 4A schematic diagram of the structure of a wound bare battery cell according to an embodiment of the present disclosure is shown. Figure 1 ; Figure 5 A schematic diagram of the structure of a wound bare battery cell according to an embodiment of the present disclosure is shown. Figure 2 ; Figure 6 This diagram shows a schematic representation of the battery cell structure before series welding, according to an embodiment of the present disclosure. Figure 7 A schematic diagram of the structure of the battery cell after series welding according to an embodiment of the present disclosure is shown; Figure 8 A schematic diagram of a battery cell structure according to an embodiment of the present disclosure is shown; Figure 9 A schematic flowchart illustrating a method for manufacturing a battery cell structure according to an embodiment of the present disclosure is shown. Detailed Implementation

[0018] To make the objectives, features, and advantages of this disclosure more apparent and understandable, the technical solutions in the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. Based on the embodiments of this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure.

[0019] Figure 1 This diagram illustrates the structure of a high-capacity battery cell with 2 cells in 1 pack in the prior art. Figure 2 This diagram illustrates the structure of a conventional 3-cell-in-1-pack battery cell in the prior art. Figure 1 The first example shows a "large capacity, small quantity" battery cell, which uses a two-series-one-parallel structure (2S1P), meaning two cells are connected in series and one group is connected in parallel, i.e., there is no parallel connection. The second example shows a three-series-one-parallel structure (3S1P), meaning three cells are connected in series and one group is connected in parallel, i.e., there is no parallel connection.

[0020] like Figure 2As shown, a battery composed of large-capacity cells with a small number of series-connected cells can reduce the total number of cells in the battery pack, thereby reducing the cost of raw materials and battery assembly. However, due to the reduced number of cells connected in series, the undervoltage of a single cell will increase significantly under extreme high-power discharge load conditions. When the battery is in a low-charge state, if it encounters a sudden high-power power demand, the cell voltage will be quickly pulled down to the shutdown protection voltage (such as cell undervoltage), directly causing devices such as laptops to be forced to shut down.

[0021] like Figure 1 Large-capacity battery cells and Figure 2 Taking a conventional battery cell as an example, the discharge cutoff voltage of a three-cell series-parallel battery is 3V × 3 cells = 9V, while that of a two-cell series-parallel battery becomes 3V × 2 cells = 6V, resulting in a significant drop in the lower limit voltage at which the battery can operate normally. Under the same undervoltage protection voltage (conventional 6.5V@≥15degC, i.e., the protection threshold of 6.5V at 15 degrees Celsius and above), the voltage drop across a single cell in a two-cell series-parallel battery is 3.25V, far higher than the approximately 2.17V voltage drop across a single cell in a three-cell series-parallel battery.

[0022] In overload discharge scenarios, the cell voltage of two batteries connected in series is more easily pulled down below the undervoltage protection voltage (3.25V), triggering the battery circuit cutoff protection. In actual device use, when running high-power OLED programs or multiple software programs running in parallel, the battery discharge power increases dramatically in an instant. Under low charge and instantaneous high-power discharge conditions, the two-cell-connected batteries are very likely to reach the shutdown voltage (3.25V), ultimately causing the computer to shut down unexpectedly, seriously affecting the stability of device operation and user experience.

[0023] Figure 8 A schematic diagram of a battery cell structure according to an embodiment of the present disclosure is shown, as follows: Figure 8 As shown, a battery cell structure includes an outer packaging structure and a wound bare battery cell encapsulated within the outer packaging structure. The wound bare battery cell is formed by sequentially connecting at least two winding units along the winding direction. The winding unit includes a positive electrode plate, a negative electrode plate, and a diaphragm disposed between the two. The lengths of the positive and negative electrode sheets in adjacent winding units are the same or different, or the number of positive and negative electrode sheets in adjacent winding units is the same or different.

[0024] In this embodiment, Figure 8Only the outer packaging structure of the battery cell is shown; the wound bare battery cell encapsulated within the outer packaging structure is not shown. The outer packaging structure, used to seal and protect the internal electrochemical components, is a packaging bag or a film layer covering the bare battery cell, preventing electrolyte leakage and external environmental intrusion. The outer packaging structure can be an aluminum-plastic film flexible packaging structure, typically composed of an outer nylon layer, a middle aluminum foil layer, and an inner polypropylene heat-sealing layer. The outer packaging structure forms a sealed containment cavity, the specific shape of which can be designed as square, cylindrical, or other irregularly shaped structures adapted to the internal space of the electronic product, depending on the shape of the battery cell. The outer packaging structure includes a top seal, side seals, and a bottom seal.

[0025] In this embodiment, the wound bare cell is formed by at least two winding units connected sequentially along the winding direction. The winding direction refers to the spiral extension direction from the winding start end to the winding end end. Each winding unit is arranged sequentially along this direction. The inner winding unit is located in the central region of the winding structure, and the outer winding unit is sequentially wrapped around the outer periphery of the inner winding unit. Each winding unit can be connected to each other through a diaphragm.

[0026] In this embodiment, each winding unit includes a positive electrode, a negative electrode, and a separator disposed between them. The positive electrode consists of a positive current collector (typically aluminum foil, 10 μm to 20 μm thick) and a positive active material layer coated on the surface of the positive current collector. The positive active material layer contains lithium transition metal oxides (such as lithium cobalt oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, etc.), conductive agents (such as acetylene black, carbon nanotubes), and binders (such as polyvinylidene fluoride). The negative electrode consists of a negative current collector (typically copper foil, 6 μm to 12 μm thick) and a negative active material layer coated on the surface of the negative current collector. The negative active material layer contains graphite, silicon-based materials or other materials capable of inserting / extracting lithium ions, conductive agents, and binders (such as styrene-butadiene rubber, carboxymethyl cellulose). The separator is disposed between the positive and negative electrode to prevent direct contact between the positive and negative electrodes from causing a short circuit, while allowing lithium ions to pass freely during charging and discharging. The diaphragm can be a single-layer polyethylene (PE) or polypropylene (PP) diaphragm, or a three-layer PE / PP / PE composite diaphragm, with a diaphragm thickness typically ranging from 9μm to 25μm.

[0027] In this embodiment, the length of the winding unit can be determined based on the circumference of each turn of the bare battery cell. For example, the length of the winding unit can be 1 to 10 times the circumference of the bare battery cell, preferably 2 to 6 times. Since the layers of the bare battery cell are very compact and each layer is very thin, the difference in circumference between each turn of the bare battery cell is very small and can be disregarded. Therefore, the circumference of each turn of the bare battery cell can be a fixed value. The circumference of the bare battery cell can be determined based on the width of the bare battery cell. For example, the difference between the circumference of the bare battery cell and twice the width of the bare battery cell can be less than a first threshold, that is, the circumference of each turn of the bare battery cell can be approximately equal to twice the width of the bare battery cell.

[0028] Figure 3 A schematic diagram of the structure of a winding unit in the prior art is shown, such as... Figure 3 As shown, the winding unit includes a negative electrode 10, a separator 20, a positive electrode 30 and a separator 20 from top to bottom. The positive electrode and the negative electrode are arranged in parallel within the winding unit, and a uniform spacing is maintained between them. This spacing is controlled by the thickness of the separator.

[0029] Figure 4 A schematic diagram of the structure of a wound bare battery cell according to an embodiment of the present disclosure is shown. Figure 1 ,like Figure 4 As shown, a wound bare battery cell is formed by two wound units (a first winding unit and a second winding unit) connected sequentially (before winding). The first winding unit is located on the inner ring of the winding structure (close to the winding axis), and the second winding unit is located on the outer ring of the winding structure. The two winding units are physically connected and electrically insulated from each other by a continuous diaphragm. Of course, depending on the actual application scenario, a third, fourth, fifth, etc., winding unit can be connected after the second winding unit.

[0030] Figure 5 A schematic diagram of the structure of a wound bare battery cell according to an embodiment of the present disclosure is shown. Figure 2 ,like Figure 5 As shown, if a wound bare cell is formed by three winding units (winding unit 1, winding unit 2 and winding unit 3) connected and wound together, where winding unit 1 is located in the inner ring of the winding structure (close to the winding axis), winding unit 3 is located in the outer ring of the winding structure, and winding unit 2 is located between winding structure 1 and winding unit 3.

[0031] In this embodiment, the positive and negative electrode sheets in adjacent winding units of the wound bare cell may have the same or different lengths. When the positive and negative electrode sheets in adjacent winding units have the same length, each winding unit has the same theoretical capacity and similar internal resistance characteristics, which is beneficial for achieving balanced charging and discharging behavior and consistent overcurrent capability. When the positive and negative electrode sheets in adjacent winding units have different lengths, the positive and negative electrode sheets of different winding units can be differentially cut according to the cell voltage and capacity design goals. Longer positive and negative electrode sheets are used to provide higher capacity and voltage output, while shorter positive and negative electrode sheets are used to adapt to the overall winding size and splicing structure requirements of the cell. The difference in electrode length can be directly achieved through the cutting process after coating without changing the electrode's own composition and material system.

[0032] In this embodiment, the number of positive and negative electrode sheets in adjacent winding units may be the same or different. When the number of positive and negative electrode sheets in adjacent winding units is the same, their structures can be identical. For example, the first winding unit contains one positive electrode sheet and one negative electrode sheet, and the second winding unit also contains one positive electrode sheet and one negative electrode sheet. This structure is simple, easy to control in terms of process, and the electrochemical characteristics of each winding unit are highly consistent. When the number of positive and negative electrode sheets in adjacent winding units is different, one winding unit may contain n positive electrode sheets or n negative electrode sheets, and the other winding unit may contain m positive electrode sheets or m negative electrode sheets, where n and m are different. For example, the first winding unit contains one positive electrode and one negative electrode, and the second winding unit contains two positive electrode and two negative electrode. The capacity of the second winding unit is about twice that of the first winding unit. The two positive electrode pieces in the second winding unit are connected in parallel through tabs to form a positive parallel group, and the two negative electrode pieces are connected in parallel through tabs to form a negative parallel group. The positive parallel group and the negative parallel group are then connected in series with the positive and negative electrode pieces of the first winding unit.

[0033] In this disclosure, a wound bare cell, formed by at least two winding units sequentially connected along the winding direction and encapsulated in an outer packaging structure, can form a voltage output base of multiple units within a single cell. This effectively increases the rated output voltage of a single cell, thereby raising the overall lower limit of the battery's operating voltage while maintaining the cost advantage of large capacity and fewer cells. In usage scenarios with low charge and instantaneous high-power discharge, it reduces the voltage drop borne by a single cell, alleviating the problem of rapid voltage drop under extreme discharge load. It also prevents the cell voltage from being pulled below the undervoltage protection voltage, thus avoiding the protection mechanism that triggers circuit cutoff. At the same time, the length and number of positive and negative electrode plates can be flexibly adjusted between adjacent winding units, ensuring the uniformity of current carrying during cell discharge and further maintaining stable cell voltage output. From a structural perspective, this solves the problem of large-capacity cells with few series and parallel cells easily triggering shutdown due to low-voltage load, leading to unexpected shutdown of electronic devices, and significantly improving the stability of equipment use and user experience.

[0034] In another embodiment, the positive and negative electrode sheets in adjacent winding units are of the same length so that the overcurrent capacity of each winding unit is consistent in the series state; and / or, the spacing between the electrode sheets of adjacent winding units ranges from the width of the first layer to the width of the fourth layer of the wound bare cell.

[0035] In this embodiment, to ensure consistent current-carrying capacity of each winding unit in series, the lengths of the positive and negative electrode plates in adjacent winding units can be set to be the same. Specifically, the length of the positive electrode plate in the first winding unit is equal to the length of the positive electrode plate in the second winding unit, and the length of the negative electrode plate in the first winding unit is equal to the length of the negative electrode plate in the second winding unit. For example, the length of the positive electrode plate in the first winding unit is 500mm and the length of the negative electrode plate is 510mm, and the length of the positive electrode plate in the second winding unit is 500mm and the length of the negative electrode plate is 510mm. When the electrode plate lengths of adjacent winding units are the same, the amount of active material coating in each winding unit is the same, and the theoretical capacity is equal. In series operation, each winding unit shares the same voltage, and the current distribution is uniform. Therefore, each winding unit can have consistent current-carrying capacity in series operation. Consistent overcurrent capacity means that during series discharge, each winding unit can withstand the same current density and will not reach its limit prematurely due to the weaker overcurrent capacity of a certain winding unit, thus limiting the overall performance.

[0036] In this embodiment, each adjacent winding unit consists of one positive electrode and one negative electrode; that is, each winding unit is a single positive electrode and a single negative electrode structure, rather than a structure of multiple positive electrodes in parallel or multiple negative electrodes in parallel. For example, the first winding unit contains one positive electrode and one negative electrode, and the second winding unit also contains one positive electrode and one negative electrode.

[0037] In this embodiment, the spacing between the electrodes of adjacent winding units refers to the diaphragm length distance between the tail of the electrode of the first winding unit and the head of the electrode of the second winding unit along the winding direction. This spacing is determined by the difference in the starting positions of adjacent winding units in the winding process, and the spacing between adjacent electrodes can range from the width of the first layer to the width of the fourth layer of the wound bare cell, preferably the width of the second layer.

[0038] In this embodiment, the width of the first layer of the wound bare cell refers to the radial thickness of the first layer of winding (i.e., the innermost layer), measured from the winding axis, typically ranging from 0.5 mm to 2 mm, determined by the electrode thickness, separator thickness, and winding tension. The width of the fourth layer refers to the cumulative radial thickness of the first four layers of winding, measured from the winding axis, typically ranging from 2 mm to 8 mm. Figure 5As shown, the width of each layer can be calculated along the width direction of the wound bare cell. The spacing between adjacent positive electrode plates is set to the width of the first layer to the width of the fourth layer. That is, during the winding process, after the first winding unit completes winding, the starting position of the positive electrode plate of the second winding unit and the ending position of the positive electrode plate of the first winding unit are separated by a winding thickness of 1 to 4 layers. Alternatively, the spacing between adjacent negative electrode plates is set to the width of the first layer to the width of the fourth layer. That is, during the winding process, after the first winding unit completes winding, the starting position of the negative electrode plate of the second winding unit and the ending position of the negative electrode plate of the first winding unit are separated by a winding thickness of 1 to 4 layers.

[0039] In this disclosure, by setting the lengths of the positive and negative electrode plates of adjacent winding units to be the same, each winding unit has the same capacity and internal resistance in the series state, thereby achieving consistent overcurrent capability. This avoids the problem of insufficient overcurrent capability of a certain winding unit becoming a bottleneck in the overall performance, ensuring that each winding unit reaches its limit synchronously when the cell is discharged at a high rate, thus improving the stability and reliability of power output. By setting each adjacent winding unit to a single-electrode structure consisting of one positive electrode plate and one negative electrode plate, the internal structure of the winding unit is simplified, avoiding the problems of electrode tab welding complexity and internal resistance non-uniformity caused by multi-electrode parallel connection. By limiting the spacing between adjacent positive electrode plates to the width of the first to fourth layers of the wound bare cell, the internal spatial layout of the bare cell is optimized while ensuring the insulation reliability between adjacent winding units. This avoids the short-circuit risk caused by too small a spacing and the volumetric energy density reduction caused by too large a spacing, achieving a balance between safety and energy density.

[0040] In another embodiment, the wound bare cell is formed by connecting the positive electrode tabs of each winding unit to the negative electrode tabs of adjacent winding units in series to form a series structure within the wound bare cell. The positive or negative tab of the innermost winding unit and the negative or positive tab of the outermost winding unit of the wound bare cell are respectively led out to the outside of the outer packaging structure as the positive and negative tabs of the cell structure.

[0041] In this embodiment, each winding unit has a positive electrode tab in its positive electrode plate and a negative electrode tab in its negative electrode plate. For example... Figure 3As shown, the positive electrode 30 has a positive electrode tab 50, and the negative electrode 10 has a negative electrode tab 40. The positive electrode tab is made of aluminum foil or aluminum strip, with a thickness of 0.1 mm to 0.3 mm and a width of 3 mm to 10 mm. One end is welded to the positive current collector, and the other end extends to the outside of the winding unit. The number of positive electrode tabs in one winding unit can be 1 to 4, preferably 1. The negative electrode tab is made of nickel sheet, copper sheet, nickel-plated copper sheet, or nickel-plated copper alloy sheet, preferably nickel-plated copper sheet. It has a thickness of 0.1 mm to 0.3 mm and a width of 3 mm to 10 mm. One end is welded to the negative current collector, and the other end extends to the outside of the winding unit. The number of negative electrode tabs in one winding unit can be 1 to 4, preferably 1.

[0042] In this embodiment, the series structure within the wound bare cell is achieved through tab welding, that is, the positive tab of the nth winding unit is welded in series with the negative tab of the (n+1)th winding unit to form a series relationship between adjacent winding units. Tab welding employs metal welding processes, including ultrasonic welding, laser welding, or resistance welding. The welding material is a metal that matches the tab material, such as aluminum, nickel, copper, or nickel-plated copper.

[0043] In one example, the alternating welding process of the positive and negative tabs can be as follows: the positive tab of the first winding unit and the negative tab of the second winding unit are welded to form a first welding node; the positive tab of the second winding unit and the negative tab of the third winding unit are welded to form a second welding node, and so on, until all winding units are connected in series. Each welding node forms a current path between the winding units.

[0044] In this embodiment, after the wound bare cell completes its internal series connection, two tabs that are not involved in the series welding are reserved as the overall positive and negative output terminals of the cell structure. That is, the wound bare cell contains multiple wound units connected in series sequentially. Adjacent wound units are connected in series by welding positive and negative tabs together. After the series connection is completed, only one tab on the innermost wound unit and one tab on the outermost wound unit that are not involved in the series welding are retained as the external tabs for the entire cell structure to output electrical energy. In one example, if the innermost wound unit retains the positive tab, then the outermost wound unit retains the negative tab; conversely, if the innermost wound unit retains the negative tab, then the outermost wound unit retains the positive tab. After the cell is packaged, these two reserved tabs extend outward from the preset lead-out positions on the outer packaging structure, serving as the positive and negative terminals of the entire cell structure.

[0045] In one example, when the wound bare cell contains two winding units, the negative electrode tab of the first winding unit is welded in series with the positive electrode tab of the second winding unit. The innermost first winding unit retains the positive electrode tab, and the outermost second winding unit retains the negative electrode tab. The two electrodes with opposite polarities are led out to the outside of the outer packaging structure. When the wound bare cell contains three winding units, the positive and negative electrodes of adjacent winding units are welded in sequence. Finally, the innermost winding unit retains one polarity tab, and the outermost winding unit retains the opposite polarity tab, thus forming a positive and negative external lead-out tab structure.

[0046] Figure 6 A schematic diagram of the battery cell structure before series welding according to an embodiment of this disclosure is shown, as follows: Figure 6 As shown, after winding the bare battery cell, it is necessary to connect the positive electrode tab of each winding unit to the negative electrode tab of the adjacent winding unit in series. The electrodes to be connected in series are as follows: Figure 6 The polar ear in the shaded area; and Figure 6 The tabs in the blank part are the positive and negative tabs that are drawn out.

[0047] In this disclosure, by connecting the positive electrode tabs of each winding unit to the negative electrode tabs of adjacent winding units in series, a reliable series structure is formed inside the wound bare cell. This achieves electrical series integration of multiple winding units, increasing the voltage of a single cell to the sum of the voltages of multiple winding units. This effectively solves the problem in traditional solutions where a battery is composed of a large-capacity and a small number of independent cells, resulting in excessive voltage division of a single cell and the risk of being pulled below the CUV voltage under low SOC and high-power scenarios, leading to unexpected shutdown of electronic devices. By using the unwelded tabs of the innermost and outermost winding units as the positive and negative electrodes of the cell structure, a standardized interface between the series-connected cell structure and the external circuit is achieved. This maintains the same packaging form and connection method as a conventional single-wound cell, facilitating direct replacement in existing battery pack designs.

[0048] In another embodiment, the positive electrode tab and the negative electrode tab are respectively located at the middle position along the length direction of the positive electrode sheet and the negative electrode sheet of each winding unit; and / or, After the wound bare cell is packaged into the outer packaging structure, the tabs that are connected in series are folded into the top seal of the outer packaging structure.

[0049] In this embodiment, in each independent winding unit structure, the positive electrode tab is not located at the end of the positive electrode sheet, but is fixedly welded to the middle region along the length of the positive electrode sheet. Similarly, the negative electrode tab is also fixedly welded to the middle region along the length of the negative electrode sheet. The middle region refers to the area within 50% ± 10% of the length direction from the tip of the electrode sheet. Placing the tab in the middle of the length direction of the electrode sheet allows for uniform current conduction during charging and discharging, reduces local current density differences, and facilitates alignment welding of the tabs between adjacent winding units, avoiding interference, misalignment, or tearing problems that can occur during winding if the tabs are located at the ends.

[0050] In this embodiment, after the positive and negative tabs of the wound bare cell are connected in series between adjacent winding units, the entire bare cell is encapsulated inside the outer packaging structure. Before the encapsulation and top sealing processes are completed, the welding tabs used to achieve internal series connection are folded towards the top of the cell, so that these tabs fit flat against the top sealing area of ​​the outer packaging structure and are then insulated with adhesive. After the tabs are folded to the top sealing part, the tabs can be fixed to the inner film of the outer packaging structure through the top sealing heat pressing process, achieving insulation positioning and mechanical fixation of the tabs. This prevents the internal tabs from shaking, shifting, or puncturing the diaphragm during the use of the cell, while not occupying the effective internal space of the cell, ensuring the compactness of the cell structure.

[0051] Figure 7 A schematic diagram of the structure of the battery cell after series welding according to an embodiment of this disclosure is shown, as follows: Figure 7 As shown in the diagram, the shaded area represents the tabs that are folded into the top seal of the outer packaging structure after being tandemly welded; and Figure 7 The tabs in the blank part are the positive and negative tabs that are drawn out.

[0052] In another embodiment, the number of positive and / or negative electrode plates in adjacent winding units is different; The same winding unit includes at least two positive electrode plates or at least two negative electrode plates, and the positive electrode plates or the negative electrode plates are connected by electrode tabs; and / or, Different electrodes within the same winding unit may have different specifications or electrochemical properties.

[0053] In this embodiment, two adjacent winding units connected sequentially along the winding direction contain different total numbers of positive electrode sheets, or different total numbers of negative electrode sheets, or different numbers of both positive and negative electrode sheets. This difference in quantity can be achieved by segmenting the electrode sheets. For example, one winding unit uses a single complete electrode sheet, while another adjacent winding unit uses multiple electrode sheets spliced ​​together, thus creating a difference in quantity to adapt to the voltage and capacity ratio requirements of multiple units connected in series within the battery cell. In one example, one winding unit contains one positive electrode sheet and one negative electrode sheet, while adjacent winding units contain two positive electrode sheets and two negative electrode sheets. The two units have different numbers of electrode sheets and can be connected along the winding direction to form a wound bare battery cell.

[0054] In this embodiment, when multiple electrodes of the same polarity are contained within the same winding unit, these electrodes are connected in parallel via tab busbars. Tab busbar connection refers to welding the tabs of multiple electrodes to the same busbar conductor, or multiple electrodes connecting through the same tab. The multiple electrodes connected in a busbar configuration can be considered as multiple sub-parts of the same polarity electrode. In one example, the busbar connection between positive electrodes uses an aluminum busbar or direct tab lap welding, with ultrasonic welding or laser welding as the welding method. After welding, multiple positive electrodes form an equipotential connection, and the current can be evenly distributed among each positive electrode. The busbar connection between negative electrodes uses a nickel, copper, or copper-plated nickel busbar, or direct tab lap welding, with the welding method the same as for the positive electrode. After welding, multiple negative electrodes form an equipotential connection. The busbar connection is located at the middle or head of the electrode along its length.

[0055] In this embodiment, multiple positive electrodes, multiple negative electrodes, or multiple positive and negative electrodes within the same winding unit can be combined with electrode combinations of different specifications or electrochemical performance. Specifications include dimensional parameters such as electrode length, thickness, and width, as well as parameters such as the number, position, and size of tabs, and the length of the coated area and the empty foil area. Electrochemical performance includes capacity performance (specific capacity, areal capacity, and single-turn capacity determined by length), rate performance (fast charging / high-current discharge capability), voltage plateau (charge and discharge voltage range), polarization / internal resistance (internal resistance magnitude, heat generation), cycle life (cycle decay rate), and low-temperature / high-temperature performance (low-temperature discharge, high-temperature stability). By using differentiated electrode combinations, the output characteristics of the winding unit can be flexibly adjusted, achieving a balance between capacity, power, and voltage stability of the battery cell, meeting the requirements of low-SOC, high-power discharge scenarios.

[0056] In this disclosure, by differentiating the number of electrodes in adjacent winding units, connecting multiple electrodes within the same winding unit, and combining electrodes with different performance characteristics, the cell structure has greater design flexibility and adjustable electrical performance. This can improve the overall overcurrent capacity and discharge stability of the cell, alleviate the problem of voltage drop under high power load, further prevent the cell voltage from being pulled below the undervoltage protection threshold, and reduce the occurrence of unexpected equipment shutdowns.

[0057] In another embodiment, the number of winding units in the wound bare cell is 2 to 10, and the number of winding units is determined based on the ratio between the total battery capacity and the capacity of the original cell replaced by the cell structure, and the ratio between the total battery capacity and the capacity of the cell structure.

[0058] In this embodiment, the number of winding units constituting the wound bare battery cell is no less than 2 and no more than 10. This range is a reasonable range determined after comprehensively considering the overall output voltage requirements of the battery cell, the utilization rate of internal space, the feasibility of the winding process, and the stability of high-power discharge. If the number is too small, the voltage platform of the battery cell cannot be effectively improved; if the number is too large, it will lead to a complex internal structure of the battery cell, increased difficulty in winding and forming, and too many tab connection points, which is not conducive to the reliability of the battery cell. The preferred number of winding units is 2 to 4.

[0059] In this embodiment, the specific number of winding units is not arbitrarily set, but is matched and calculated according to actual application requirements. First, the total battery capacity of the target battery, the capacity of the conventional battery cell to be replaced by this cell structure, and the design capacity required by this cell structure are determined. Then, the ratio of the total battery capacity to the capacity of other cells is calculated to determine the number of conventional cells required for the entire battery when using other cells. The ratio of the total battery capacity to the design capacity required by this cell structure is calculated to determine the number of large cells (this cell structure) required for the entire battery when using this cell structure. Finally, the ratio of the number of conventional cells required for the entire battery to the number of large cells required for the entire battery is calculated to obtain the number of winding units. If the ratio is not an integer, it is rounded up.

[0060] In this embodiment, the number of winding units can be calculated based on the following formula:

[0061] In this embodiment, the voltage of the large battery cell can be calculated based on the following formula:

[0062] In this embodiment, the capacity range of large cells is 25Wh~50Wh, and the capacity range of conventional cells is 5Wh~20Wh. The relationship between cell capacity can be defined by inversely calculating the series and parallel cells based on the total battery capacity. In one example, If the total battery capacity is 60Wh, the large cell can be 30Wh with a 2S1P structure, and the conventional cell is 15Wh with a 4S1P structure, then the number of winding units is 2. The calculation process is: 60Wh ÷ 15Wh = 4; 60Wh ÷ 30Wh = 2; 4 ÷ 2 = 2 units; If the total battery capacity is 60Wh, the large cell can be 30Wh with a 2S1P structure, and the conventional cell is 20Wh with a 3S1P structure, then the number of winding units is 2. The calculation process is as follows: 60Wh ÷ 20Wh = 3; 60Wh ÷ 30Wh = 3; 3 ÷ 2 = 1.5, rounded up to 2.

[0063] In this disclosure, by limiting the number of winding units to a reasonable range of 2 to 10, the overall voltage of the cell can be increased through the series connection of multiple internal units, while also taking into account the feasibility of manufacturing processes and structural stability, avoiding structural defects and performance deficiencies caused by too many or too few units. Furthermore, the number of winding units can be precisely determined based on the total battery capacity, the capacity of the cell to be replaced, and the capacity of the current cell itself, ensuring that the cell structure accurately matches the electrical parameter requirements of the target device.

[0064] In another embodiment, this disclosure also provides a battery, comprising: The encapsulation housing has a receiving cavity filled with a high-voltage electrolyte. A cell structure disposed within a receiving cavity, the cell structure including an outer packaging structure and a wound bare cell encapsulated within the outer packaging structure, the wound bare cell being formed by at least two winding units sequentially connected along the winding direction; The winding unit includes a positive electrode sheet, a negative electrode sheet, and a diaphragm disposed between the two. The lengths of the positive and negative electrode sheets in adjacent winding units are the same or different, or the number of positive and negative electrode sheets in adjacent winding units is the same or different.

[0065] In this embodiment, the battery uses a casing as its external main structure. The casing is made of rigid or semi-rigid insulating material, and a closed cavity is formed inside the casing. This cavity is used to house the battery cell structure and fill it with electrolyte. The electrolyte is a high-voltage electrolyte suitable for high-voltage operating scenarios. This high-voltage electrolyte can maintain chemical stability under the high voltage platform formed by multiple winding units connected in series inside the battery cell, and is not prone to oxidation and decomposition, ensuring the battery's cycle performance and safety performance under high voltage and high power discharge conditions. The number of battery cell structures in the cavity can be set according to actual application requirements, and can be 1 to 2. The battery cell structures set in the cavity have been described in detail above and will not be repeated here.

[0066] In this disclosure, by setting up a battery cell with a multi-wound unit connection structure in the encapsulation housing and using a high-voltage electrolyte, the battery's operating voltage platform is effectively improved while maintaining the overall battery capacity and using a smaller number of battery cells. This reduces the voltage drop of the battery under low charge and high power discharge conditions, and prevents the battery voltage from being pulled below the undervoltage protection voltage, thus triggering the circuit to cut off protection. This solves the problem of unexpected shutdown of electronic devices due to abnormal battery power supply at the system level, while also taking into account the battery's manufacturing cost and structural compactness, thereby improving the overall reliability of the battery and the user experience.

[0067] In another embodiment, the high-voltage electrolyte includes a lithium salt, an organic solvent, and functional additives; The mass percentage of lithium salt in the high-voltage electrolyte is 7% to 15%. The organic solvent content in the high-voltage electrolyte is 70%~90% by mass; The functional additives have a mass percentage content of 3% to 15% in the high-voltage electrolyte.

[0068] In this embodiment, the high-voltage electrolyte includes lithium salt, organic solvent and functional additives. The components work synergistically to adapt to the high-voltage working platform formed by multiple units connected in series inside the battery cell. Under high voltage conditions, it still has excellent antioxidant stability, ion conduction ability and interfacial film formation performance, avoiding decomposition and gas generation of the electrolyte under high voltage and high power discharge conditions, and ensuring the safety and cycle stability of the battery during long-term operation.

[0069] In this embodiment, the lithium salt serves as the lithium ion provider in the high-voltage electrolyte, and its mass percentage is controlled within the range of 7% to 15%. This content range ensures that there are sufficient dissociated lithium ions in the electrolyte to meet the ion transport requirements during battery charging and discharging. At the same time, it avoids problems such as insufficient electrolyte conductivity due to excessively low lithium salt content, or uneven dissolution, increased viscosity, and decreased low-temperature performance due to excessively high lithium salt content.

[0070] In this embodiment, the organic solvent serves as the main dispersion medium for the high-voltage electrolyte, with a mass percentage of 70% to 90%. It is mainly used to dissolve lithium salts and provide a continuous medium for lithium-ion migration, while also balancing dielectric constant and viscosity. This ensures that lithium ions can be transported quickly and stably within the multi-wound unit structure inside the cell, thereby improving the battery's rate discharge performance and voltage output stability.

[0071] In this embodiment, the functional additive is added to the high-voltage electrolyte at a mass percentage of 3% to 15% to form a stable and dense solid electrolyte interface film on the surface of the positive and negative electrode plates, suppressing the side reactions of the electrolyte under high voltage, reducing the battery self-discharge rate, and improving the voltage stability of the cell when it is under low charge and high power discharge, thus delaying the voltage from dropping rapidly below the undervoltage protection threshold.

[0072] In this disclosure, by limiting the composition and mass percentage of each component of the high-voltage electrolyte, the electrolyte system can be matched with the high-voltage operating environment of multi-wound unit series cells. While ensuring efficient lithium-ion conduction, it improves chemical stability under high voltage, effectively reduces the occurrence of side reactions, and lowers the cell internal resistance and voltage decay rate. This alleviates the problem of the battery voltage being pulled below the undervoltage protection voltage CUV during high-power discharge, avoids the trigger circuit cut-off protection causing unexpected shutdown of electronic devices, and improves the overall reliability of the battery and the user experience.

[0073] In another embodiment, the lithium salt is lithium hexafluorophosphate; The organic solvent is a mixture of ethylene carbonate, propylene carbonate, diethyl carbonate and a high-voltage solvent, with a mass ratio of 1:1:2:(1~10). The high-voltage solvent is a combination of at least two of sulfolane, dimethyl sulfone, n-butyl sulfone, diethyl sulfone, sulfone phenyl sulfone, methyl ethyl sulfone, methyl methoxy sulfone and methyl ethoxy sulfone. The functional additive is at least one of sulfone solvents, nitrile solvents and their ether derivatives.

[0074] In this embodiment, the lithium salt in the high-voltage electrolyte can be lithium hexafluorophosphate (LiPF6), which possesses excellent ion dissociation, high conductivity, and good electrochemical stability, making it suitable for high-voltage operating platforms formed by multiple wound cells connected in series (with higher voltages compared to conventional single-wound cell batteries). Lithium hexafluorophosphate can rapidly dissociate into lithium ions in the electrolyte, providing an ample source for lithium ion migration during battery charging and discharging. Furthermore, its chemical properties are stable, and it is well-compatible with organic solvents and functional additives, without significant side reactions.

[0075] In this embodiment, the organic solvent is a mixture of ethylene carbonate (EC), propylene carbonate (PC), diethyl carbonate (DEC), and a high-voltage solvent. Ethyl carbonate has a high dielectric constant, which can effectively dissolve lithium hexafluorophosphate and provide a good environment for lithium-ion dissociation. Propylene carbonate can improve the low-temperature fluidity of the electrolyte and avoid the decrease in ion transport rate caused by the increase in electrolyte viscosity at low temperatures. Diethyl carbonate has a low viscosity, which can reduce the overall viscosity of the electrolyte and improve the lithium-ion migration rate. The three components can achieve a balance between dielectric constant and viscosity, ensuring the basic ion conduction performance of the electrolyte.

[0076] In this embodiment, the high-voltage solvent is a key component of the mixed solvent, and a combination of at least two of the following is selected: sulfolane, dimethyl sulfone, n-butane sulfone, diethyl sulfone, sulfone benzene, methyl ethyl sulfone, methyl methoxy sulfone, and methyl ethoxy sulfone. These sulfone solvents possess excellent high-voltage stability and are not easily oxidized or decomposed under high-voltage conditions formed by multiple winding units connected in series. They can effectively broaden the electrochemical window of the electrolyte, avoiding decomposition, gas generation, and degradation of the electrolyte under high voltage. At the same time, they can further improve the wettability of the electrolyte to the electrodes and optimize the migration efficiency of lithium ions between the positive and negative electrodes and the separator. The mass ratio of ethylene carbonate, propylene carbonate, diethyl carbonate, and the high-voltage solvent is controlled at 1:1:2:(1~10). The proportion of the high-voltage solvent can be flexibly adjusted according to the actual operating voltage requirements of the battery. When the battery design voltage is high, the proportion of the high-voltage solvent can be appropriately increased (e.g., close to 10) to enhance the high-voltage stability of the electrolyte; when the voltage requirement is moderate, the proportion of the high-voltage solvent can be reduced (e.g., close to 1) to balance cost and performance.

[0077] In this embodiment, the functional additive is at least one of sulfone solvents, nitrile solvents, and their ether derivatives. Sulfone functional additives can form a stable, dense solid electrolyte interphase (CEI) film on the surface of the positive electrode, suppressing side reactions between the electrolyte and the positive electrode material under high voltage and reducing electrolyte decomposition losses. Nitrile solvents possess excellent antioxidant properties, which can further broaden the electrochemical window of the electrolyte and improve its high-voltage tolerance. Ether derivatives can improve the wettability of the electrolyte to the electrode, reduce interfacial impedance, improve lithium-ion migration efficiency, and alleviate the voltage drop problem during high-power discharge under low charge conditions.

[0078] In one example, the functional additive may be succinic anion, glutaronitrile, adiponitrile, 1,5-dicyanopentane, 1,6-dicyanohexane, tetramethylsuccinic anion, 1,4-dicyanopentane, 1,2-dicyanobenzene, 1,3-dicyanobenzene, 1,4-dicyanobenzene, ethylene glycol bis(propionitrile) ether, 3,5-dioxa-heptanenitrile, 1,4-di(cyanoethoxy)butane, diethylene glycol di(2-cyanoethyl) ether, Triethylene glycol di(2-cyanoethyl) ether, tetraethylene glycol di(2-cyanoethyl) ether, 1,3-di(2-cyanoethoxy)propane, 1,4-di(2-cyanoethoxy)butane, 1,5-di(2-cyanoethoxy)pentane, ethylene glycol di(4-cyanobutyl) ether, 1,4-dicyano-2-butene, 1,4-dicyano-2-methyl-2-butene, 1,4-dicyano-2-ethyl-2-butene 1,4-Dicyano-2,3-dimethyl-2-butene, 1,4-dicyano-2,3-diethyl-2-butene, 1,6-dicyano-3-hexene, 1,6-dicyano-2-methyl-3-hexene, 1,3,5-pentanetricarbonitrile, 1,2,3-propanetricarbonitrile, 1,3,6-hexanetricarbonitrile, 1,2,6-hexanetricarbonitrile, 1,2,3-tris(2-cyanoethoxy)propane, 1,2 Combinations of two or more substances selected from the following: 4-tris(2-cyanoethoxy)butane, 1,1,1-tris(cyanoethoxymethylene)ethane, 1,1,1-tris(cyanoethoxymethylene)propane, 3-methyl-1,3,5-tris(cyanoethoxy)pentane, 1,2,7-tris(cyanoethoxy)heptane, 1,2,6-tris(cyanoethoxy)hexane, and 1,2,5-tris(cyanoethoxy)pentane.

[0079] In this disclosure, by further specifying the components of the high-voltage electrolyte, the specific types and proportions of lithium salt, mixed organic solvent and functional additives are clarified, so that the electrolyte system can be more accurately adapted to the high-voltage working environment of the multi-wound unit series of this battery.

[0080] Figure 9 This illustration shows a flowchart of a method for manufacturing a battery cell structure according to an embodiment of the present disclosure, such as... Figure 9 As shown, a method for manufacturing a battery cell structure includes: Step S101: Based on at least two winding units, they are sequentially connected and wound along the winding direction to form a wound bare cell.

[0081] In this embodiment, at least two independent winding units are first prepared. Each winding unit consists of a positive electrode, a negative electrode, and a separator. The separator is spaced between the positive and negative electrodes to achieve physical isolation between the positive and negative electrodes, while ensuring normal lithium-ion migration and providing a basis for subsequent charge-discharge reactions. When preparing the winding units, the length and number of electrodes in each winding unit are determined according to the overall capacity and voltage design requirements of the battery cell. The lengths of the positive and negative electrodes in adjacent winding units may be the same or different, or the number of positive and negative electrodes in adjacent winding units may be the same or different.

[0082] In one example, the positive electrode, separator, and negative electrode of a single winding unit can be stacked neatly in sequence to obtain a single winding unit. Then, at least two prepared winding units are connected sequentially along the winding direction. When connecting, the electrodes of adjacent winding units are aligned to avoid misalignment, offset, or other problems. The connected winding units are then wound together using a winding device to form an integrated wound bare cell.

[0083] Step S102: The positive electrode tabs of each winding unit in the wound bare cell are connected in series with the negative electrode tabs of the adjacent winding unit to form a series structure in the wound bare cell.

[0084] In this embodiment, before welding, it is necessary to determine the polarity of each winding unit tab to ensure that the welding positions of the positive and negative tabs of each winding unit are accurate, and to avoid short circuits or performance failures caused by reverse polarity connection. During welding, laser welding or resistance welding is used to weld the positive tab of the previous winding unit to the corresponding negative tab of the next winding unit. The welding joint must be secure, have good conductivity, and be free from defects such as poor welding, false welding, and missing welding, so as to reduce the contact resistance at the welding joint and ensure that the current can be smoothly conducted.

[0085] In one example, the wound bare battery cell after winding can be fixed on a welding fixture, the tabs of each winding unit can be sorted out, and the positive and negative tabs of adjacent winding units can be aligned. Welding parameters (such as laser power and welding time) can be adjusted, and the tabs of each group of adjacent winding units can be welded. After welding, the weld is visually inspected and a continuity test is performed to confirm that the weld is firm and undamaged. The winding units are connected in series to form a complete series circuit, ensuring that multiple winding units can work together to achieve voltage superposition effect.

[0086] Step S103: The wound bare cell is packaged into the outer packaging structure, and the tabs that are connected in series are folded to the top seal of the outer packaging structure. The positive or negative tab of the innermost winding unit that is not connected in series and the negative or positive tab of the outermost winding unit are led out to the outside of the outer packaging structure.

[0087] In this embodiment, after welding is completed, a suitable outer packaging structure (such as aluminum-plastic film) needs to be selected. The wound bare battery cell that has been series welded is placed into the receiving cavity of the outer packaging structure. The position of the bare battery cell is adjusted to ensure that it is placed neatly in the receiving cavity without displacement. Then, the tabs after series welding are processed. All the tabs used for internal series welding are folded towards the top of the outer packaging structure so that the folded tabs fit flat and fit the top sealing area (i.e., the top sealing part) of the outer packaging structure. This prevents the tabs from shaking or shifting after packaging, and prevents puncturing the outer packaging structure or diaphragm, which could lead to a short circuit risk.

[0088] After the tabs are folded, the packaging structure is sealed (e.g., thermoforming). During the sealing process, the sealing must be ensured to prevent electrolyte leakage and moisture ingress, which would affect the cell performance. Before the sealing is completed, the tabs that are not involved in the internal series welding are led out to the outside of the outer packaging structure. Since the multiple winding units are connected in series, the polarities of the tabs that are not involved in the series connection between the innermost winding unit and the outermost winding unit must be opposite. Therefore, only these two tabs with opposite polarities need to be led out to serve as the positive and negative tabs of the cell structure, respectively, for connection with external electrical equipment or battery protection board.

[0089] In one example, the wound bare battery cell can be placed in an aluminum-plastic film outer packaging. The series-welded tabs are folded to the top seal and fixed. The side seals and bottom seals of the aluminum-plastic film are heat-pressed and sealed using a thermoforming device, leaving the top seal unsealed for the time being. The unwelded tabs of the innermost winding unit (such as the positive tab) and the unwelded tabs of the outermost winding unit (such as the negative tab) are passed out from the preset lead-out positions of the top seal. The lead-out length of the tabs is adjusted to ensure smooth lead-out without bending or damage. Finally, the top seal is heat-pressed and sealed to fix the folded internal series tabs to the aluminum-plastic film top seal as one unit, completing the packaging of the entire battery cell structure and obtaining a complete battery cell structure.

[0090] In one example, the overall manufacturing process of the battery cell structure can be as follows: mixing of positive and negative electrode slurry → coating of positive and negative electrodes → cold pressing of positive and negative electrodes → slitting of positive and negative electrode sheets and separator → cutting of positive and negative electrode sheets and separator according to the length of the winding unit → welding of tabs on positive and negative electrode sheets → pre-composite and winding of positive and negative electrode sheets and separator according to the winding unit → packaging → welding and applying adhesive to tabs on the winding unit → folding the welded tabs on the winding unit to the top seal → vacuum baking → liquid injection → formation → capacity → gas bag removal → TCO welding → K-value testing → finished battery cell. A brief description of each manufacturing process is as follows: 1. Positive and negative electrode slurry mixing: The positive and negative electrode active materials, binders, conductive agents and other raw materials are mixed and stirred in proportion to prepare a uniform and stable positive and negative electrode slurry, which provides a basis for the subsequent coating process; 2. Positive and negative electrode coating: The prepared positive and negative electrode slurries are uniformly coated on the surface of the current collector, and the coating thickness and areal density are controlled to ensure uniform electrochemical performance of the electrode. 3. Cold pressing of positive and negative electrodes: The coated positive and negative electrode sheets are cold pressed to increase the compaction density of the electrode sheets, reduce the internal porosity of the electrode sheets, and optimize the ion conduction efficiency; 4. Slitting of positive and negative electrode sheets and separator: According to the size requirements of the winding unit, the cold-pressed positive and negative electrode sheets and separator are slit into strips of corresponding widths to adapt to the subsequent winding process. 5. Cut the positive and negative electrode sheets according to the length of the winding unit, and cut the diaphragm according to the length of the winding unit: Cut the positive and negative electrode sheets according to the designed length of the winding unit, and cut the diaphragm according to the length of the winding unit to ensure that the dimensions of each winding unit are accurately matched; 6. Welding of tabs on positive and negative electrode plates: Weld the tabs to the preset positions on the positive and negative electrode plates to ensure that the tabs are firmly connected to the electrode plates and have good conductivity, providing support for subsequent electrical connections; 7. Positive and negative electrode sheets and separators are pre-combined and wound according to the winding unit: The positive electrode sheet, separator and negative electrode sheet required for a single winding unit are pre-stacked and combined, and then wound into shape by the winding equipment to obtain an independent winding unit; 8. Packaging: Place the wound bare cells, which are connected and series-connected with multiple winding units, into an outer packaging structure (such as aluminum-plastic film) for initial sealing and positioning; 9. Welding and applying adhesive to the lugs of the winding unit: After welding the lugs of adjacent winding units in series, apply insulating adhesive to the weld to prevent short circuits and improve connection reliability. 10. Fold the welding tabs on the winding unit to the top seal: Fold the tabs used for internal series welding toward the top seal of the outer packaging structure to ensure that the tabs are flat and fit together to avoid displacement after packaging; 11. Vacuum baking: The packaged battery cells are vacuum baked to remove moisture and impurities from inside the cells, preventing moisture from affecting the performance of the electrolyte and the safety of the cells. 12. Electrolyte injection: Inject high-voltage electrolyte into the packaged cell to ensure that the electrolyte fully wets the positive and negative electrode plates and the separator, providing a medium for lithium-ion migration; 13. Formation: The battery cell is subjected to formation treatment after electrolyte injection to form a stable solid electrolyte interface film on the positive and negative electrode surfaces, thereby activating the electrochemical performance of the battery cell; 14. Capacity: Perform capacity testing on the formed cells to check whether the actual capacity of the cells meets the design requirements and screen qualified products; 15. Cutting the air bags: Cut and remove the air bags used for liquid injection and venting on the outer packaging of the battery cell to ensure a compact battery cell structure; 16. TCO welding: The temperature coefficient element (TCO) is welded onto the external tab of the battery cell to achieve over-temperature protection and improve safety in use; 17. K-value test: Perform a K-value (self-discharge rate) test on the battery cell to detect its self-discharge performance and ensure good storage performance. 18. Finished battery cell: After all the above processes, a finished battery cell with qualified performance and stable structure is obtained, which can be used to power electronic equipment.

[0091] In this disclosure, the method for manufacturing the battery cell structure has clear steps and feasible processes, enabling the stable fabrication of battery cell structures with multiple winding units connected in series, ensuring stable performance of the battery cell structure. By sequentially connecting and winding multiple winding units, an integrated structure of multiple units within a single battery cell is achieved, providing a structural basis for voltage superposition. Through the series welding of the tabs of adjacent winding units, a stable series path is constructed, effectively improving the overall output voltage of the battery cell. Through reasonable packaging and tab treatment, both the bare battery cell is sealed and protected, avoiding risks such as short circuits and electrolyte leakage, and the effective lead-out of the external tabs is ensured, ensuring that the battery cell can supply power normally.

[0092] It should be understood that the various forms of processes shown above can be used to rearrange, add, or delete steps. For example, the steps described in this disclosure can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this disclosure can be achieved, and this is not limited herein.

[0093] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this disclosure, "a plurality of" means two or more, unless otherwise explicitly specified.

[0094] The above description is merely a specific embodiment of this disclosure, but the scope of protection of this disclosure is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this disclosure should be included within the scope of protection of this disclosure. Therefore, the scope of protection of this disclosure should be determined by the scope of the claims.

Claims

1. A battery cell structure, comprising an outer packaging structure and a wound bare battery cell encapsulated within the outer packaging structure, wherein the wound bare battery cell is formed by sequentially connecting at least two winding units along a winding direction; wherein The winding unit includes a positive electrode plate, a negative electrode plate, and a diaphragm disposed between the two. The lengths of the positive and negative electrode sheets in adjacent winding units are the same or different, or the number of positive and negative electrode sheets in adjacent winding units is the same or different.

2. In the cell structure according to claim 1, the positive and negative electrode plates in adjacent winding units have the same length, so that the current carrying capacity of each winding unit in series is consistent; and / or, The spacing between the electrodes of adjacent winding units ranges from the width of the first layer to the width of the fourth layer of the wound bare cell.

3. The cell structure according to claim 1 or 2, wherein the wound bare cell is formed by connecting the positive electrode tabs of each winding unit to the negative electrode tabs of adjacent winding units in series to form a series structure within the wound bare cell; The positive or negative tab of the innermost winding unit and the negative or positive tab of the outermost winding unit of the wound bare cell are respectively led out to the outside of the outer packaging structure as the positive and negative tabs of the cell structure.

4. The cell structure of claim 3, wherein, The positive and negative electrode tabs are respectively located at the midpoint of the positive and negative electrode plates in the length direction of each winding unit; and / or, After the wound bare cell is encapsulated into the outer packaging structure, the tabs that are connected in series are folded to the top seal of the outer packaging structure.

5. In the cell structure according to claim 1, the number of positive and / or negative electrode plates in adjacent winding units is different; The same winding unit includes at least two positive electrode plates or at least two negative electrode plates, and the positive electrode plates or negative electrode plates are connected to each other by electrode tabs. And / or, Different electrodes within the same winding unit may have different specifications or electrochemical properties.

6. The cell structure according to claim 1, wherein the number of winding units in the wound bare cell is 2 to 10, and the number of winding units is determined based on the ratio between the total battery capacity and the capacity of the original cell replaced by the cell structure and the ratio between the total battery capacity and the capacity of the cell structure.

7. A battery, comprising: The encapsulation housing has a receiving cavity filled with a high-voltage electrolyte. The battery cell structure disposed within the receiving cavity includes an outer packaging structure and a wound bare battery cell encapsulated within the outer packaging structure. The wound bare battery cell is formed by at least two winding units sequentially connected along the winding direction. The winding unit includes a positive electrode sheet, a negative electrode sheet, and a diaphragm disposed between the two. The lengths of the positive and negative electrode sheets in adjacent winding units are the same or different, or the number of positive and negative electrode sheets in adjacent winding units is the same or different.

8. The battery according to claim 7, wherein the high-voltage electrolyte comprises lithium salt, organic solvent and functional additives; in, The lithium salt has a mass percentage content of 7% to 15% in the high-voltage electrolyte; The organic solvent in the high-voltage electrolyte has a mass percentage content of 70% to 90%. The functional additive has a mass percentage content of 3% to 15% in the high-voltage electrolyte.

9. The battery according to claim 8, wherein, The lithium salt is lithium hexafluorophosphate; The organic solvent is a mixture of ethylene carbonate, propylene carbonate, diethyl carbonate and a high-voltage solvent, with a mass ratio of 1:1:2:(1~10). The high-voltage solvent is a combination of at least two of sulfolane, dimethyl sulfone, n-butyl sulfone, diethyl sulfone, sulfone phenyl sulfone, methyl ethyl sulfone, methyl methoxy sulfone and methyl ethoxy sulfone. The functional additive is at least one of sulfone solvents, nitrile solvents and their ether derivatives.

10. A method for manufacturing a battery cell structure, comprising: A wound bare cell is formed by sequentially connecting and winding at least two winding units along the winding direction; the winding unit includes a positive electrode, a negative electrode, and a diaphragm disposed between the two; the lengths of the positive and negative electrodes in adjacent winding units are the same or different, or the number of positive and negative electrodes in adjacent winding units is the same or different. The positive electrode tabs of each winding unit in the wound bare cell are connected in series with the negative electrode tabs of the adjacent winding unit to form a series structure within the wound bare cell. The wound bare cell is packaged into an outer packaging structure, and the series-welded tabs are folded to the top seal of the outer packaging structure. The positive or negative tab of the innermost winding unit that is not series-welded and the negative or positive tab of the outermost winding unit are led out to the outside of the outer packaging structure.

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