Sodium ion battery and electric equipment

Abstract

The utility model discloses a sodium ion battery and electric equipment. The sodium ion battery comprises a plurality of sodium ion cells connected in series, a positive electrode end and a negative electrode end, in the plurality of sodium ion cells, the positive electrode lug of the first cell ranked at the first position is connected with the positive electrode end, the positive electrode lugs of the sodium ion cells except the first cell are sequentially connected with the negative electrode lugs of the last sodium ion cell, and the negative electrode lugs of the last sodium ion cell are sequentially connected with the positive electrode end. And the negative tab of the sodium ion battery cell arranged at the tail is connected with the negative electrode end. According to the sodium ion battery disclosed by the utility model, the plurality of sodium ion battery cells are connected in series, and the positive electrode end and the negative electrode end are connected to supply power to the outside, so that the single sodium ion battery can output relatively high voltage to meet the requirements of high-voltage application scenes. And the battery cells are connected in series in the single sodium-ion battery, so that gaps between the batteries during connection are saved, the space utilization rate is high, and the integration level is high.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, and more specifically, to a sodium-ion battery and an electrical device. Background Technology

[0002] The voltage of a single sodium-ion battery is limited by its chemical materials and structure, resulting in a relatively low rated voltage that is difficult to meet the requirements of some high-voltage applications. However, by connecting multiple individual sodium-ion batteries in series, the voltage limitations of a single battery can be overcome, thus satisfying the voltage requirements.

[0003] In related technologies, multiple sodium-ion batteries connected in series occupy a large space, which is not conducive to the lightweight design of products. Utility Model Content

[0004] This utility model provides a sodium-ion battery and an electrical device.

[0005] This utility model provides a sodium-ion battery, which includes a plurality of sodium-ion cells connected in series, a positive terminal, and a negative terminal. Among the plurality of sodium-ion cells, the positive tab of the first cell in sequence is connected to the positive terminal, the positive tabs of the sodium-ion cells other than the first cell are connected to the negative tabs of the previous sodium-ion cell in sequence, and the negative tab of the last sodium-ion cell in sequence is connected to the negative terminal.

[0006] Thus, in the sodium-ion battery and electrical device of this application, by connecting multiple sodium-ion cells in series and supplying power externally by connecting the positive and negative terminals, a single sodium-ion battery can output a larger voltage to meet the needs of high-voltage applications. Furthermore, connecting cells in series within a single sodium-ion battery saves space during connection, resulting in high space utilization and high integration. It also helps reduce internal resistance and improve battery consistency.

[0007] In some implementations, the positive tab of the current sodium-ion battery cell is welded to the negative tab of the previous sodium-ion battery cell by ultrasonic welding.

[0008] Thus, by connecting the positive electrode of the current sodium-ion battery cell to the negative electrode of the previous sodium-ion battery cell through ultrasonic welding, the process is simple and the connection structure is also simpler.

[0009] In some embodiments, the sodium-ion battery cell is formed by winding a core body, the core body including a positive current collector, a separator, and a negative current collector, the separator being disposed between the positive current collector and the negative current collector, a portion of the positive current collector forming the positive tab, and a portion of the negative current collector forming the negative tab.

[0010] In this way, positive and negative tabs can be formed by the positive and negative current collectors. By setting a diaphragm between the positive and negative current collectors, short circuits inside the battery cell can be avoided.

[0011] In some embodiments, the materials of the positive current collector and the negative current collector are aluminum foil.

[0012] Thus, the positive and negative current collectors are made of aluminum foil, allowing the positive and negative tabs to be directly connected by welding.

[0013] In some embodiments, the membrane material includes a microporous membrane.

[0014] Thus, by placing a microporous membrane between the positive and negative current collectors, the impact on the performance of the sodium-ion battery cell can be reduced while isolating the positive and negative current collectors.

[0015] In some embodiments, a positive electrode material layer is coated on a portion of the surface of the positive current collector, and a negative electrode material layer is coated on a portion of the surface of the negative current collector.

[0016] Thus, coating the surface of the positive current collector with a positive electrode material layer and the surface of the negative current collector with a negative electrode material layer can improve the electrochemical capability of the current collector.

[0017] In some embodiments, the positive electrode tab is formed in the region on the positive current collector where the positive electrode material layer is not coated, and the negative electrode tab is formed in the region on the negative current collector where the negative electrode material layer is not coated.

[0018] In this way, the positive and negative electrode tabs are not coated with a positive or negative electrode material layer, so that the positive and negative electrode tabs can be directly soldered.

[0019] In some embodiments, the material of the positive electrode layer includes at least one of Prussian blue analogues, layered oxides, and polyanionic compounds.

[0020] In some embodiments, the material of the negative electrode layer includes at least one of hard carbon and soft carbon.

[0021] In some embodiments, the cell directions of two adjacent sodium-ion cells are opposite, and the cell direction is from the positive tab to the negative tab of the sodium-ion cell.

[0022] In this way, the cell orientation of two adjacent sodium-ion cells is opposite, which can reduce the length of the sodium-ion cells connected in series, thus helping to reduce the size of the sodium-ion battery.

[0023] In some embodiments, the sodium-ion battery further includes an electrolyte, which may be a liquid electrolyte, a gel electrolyte, or a solid electrolyte.

[0024] Thus, sodium-ion batteries also include an electrolyte to allow sodium ions to move within the electrolyte, enabling the sodium-ion cell to charge and discharge.

[0025] In some embodiments, when the sodium-ion cell is a omnipolar cell, the positive terminal and the negative terminal are located at opposite ends of the sodium-ion battery, and the number of sodium-ion cells is odd.

[0026] Therefore, when the sodium-ion battery cell is a multi-tab cell, the positive and negative terminals must be located at opposite ends of the sodium-ion battery to provide space for the positive and negative tabs of the sodium-ion cell. This also prevents short circuits between the positive and negative tabs of the sodium-ion cell after electrolyte injection. Furthermore, the number of sodium-ion cells must be odd so that the total positive and negative tabs of the multiple sodium-ion cells connected in series are located at opposite ends.

[0027] This utility model provides an electrical device, which includes a sodium-ion battery as described in any of the above embodiments.

[0028] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0029] The above and / or additional aspects and advantages of this invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0030] Figure 1 This is a schematic diagram of a sodium-ion battery according to an embodiment of the present invention;

[0031] Figure 2 This is a schematic diagram of multiple sodium-ion battery cells connected in series according to an embodiment of this utility model;

[0032] Figure 3 This is a schematic diagram of a sodium-ion battery cell according to an embodiment of the present invention;

[0033] Figure 4 This is a schematic diagram of the core body according to an embodiment of the present utility model;

[0034] Figure 5 This is a schematic diagram of the positive electrode current collector, the diaphragm, and the negative electrode current collector according to an embodiment of this utility model;

[0035] Figure 6 yes Figure 4 A schematic diagram of the cross-section of the core along line A-A';

[0036] Figure 7 This is a comparative schematic diagram of the sodium-ion battery of this utility model and related batteries during discharge.

[0037] Explanation of reference numerals in the attached figures:

[0038] Sodium-ion battery 1000, sodium-ion cell 10, positive electrode tab 11, negative electrode tab 13, first cell 15, last cell 17, core body 19, positive current collector 191, positive electrode material layer 1911, negative electrode 50, aluminum-plastic film shell 70, solder joint 90, electrolyte 110, insulating component 130. Detailed Implementation

[0039] The embodiments of this utility model are described in detail below. Reference numerals for these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.

[0040] The voltage of a single sodium-ion battery is limited by its chemical materials and structure, resulting in a relatively low rated voltage that is difficult to meet the requirements of some high-voltage applications. However, by connecting multiple individual sodium-ion batteries in series, the voltage limitations of a single battery can be overcome, thus satisfying the voltage requirements.

[0041] In related technologies, multiple sodium-ion batteries connected in series occupy a large space, which is not conducive to the lightweight design of products.

[0042] Please see Figures 1 to 3 This utility model provides a sodium-ion battery 1000, which includes a plurality of sodium-ion cells 10 connected in series, a positive terminal 30, and a negative terminal 50. Among the plurality of sodium-ion cells 10, the positive tab 11 of the first cell 15 is connected to the positive terminal 30. The positive tabs 11 of the sodium-ion cells 10 other than the first cell 15 are connected to the negative tabs 13 of the previous sodium-ion cell 10 in sequence. The negative tabs 13 of the last sodium-ion cell 10 are connected to the negative terminal 50.

[0043] Specifically, the sodium-ion battery 1000 includes pouch cells, prismatic cells, etc. The sodium-ion battery 1000 includes multiple sodium-ion cells 10 connected in series. Each sodium-ion cell 10 includes a positive tab 11 and a negative tab 13 for transmitting electrical energy. The sodium-ion cells 10 include bitab cells, multitab cells, and omnitab cells, etc. The number of sodium-ion cells 10 is greater than or equal to two.

[0044] In this battery, the first sodium-ion cell 10 is the first cell 15, and its positive tab 11 is the total positive tab 11 of all sodium-ion cells 10 inside the sodium-ion battery 1000. The last sodium-ion cell 10 is the last cell 17, and its negative tab 13 is the total negative tab 13 of all sodium-ion cells 10 inside the sodium-ion battery 1000. The positive tab 11 of the first cell 15 is connected to the positive terminal 30 of the sodium-ion battery 1000, and the negative tab 13 of the last cell 17 is connected to the negative terminal 50 of the sodium-ion battery 1000, so as to transfer the electrical energy of the cell to the outside of the battery.

[0045] The positive tab 11 of the sodium-ion battery cell 10 other than the first battery cell 15 is connected to the negative tab 13 of the previous sodium-ion battery cell 10. That is, in two adjacent sodium-ion battery cells 10, the positive tab 11 of the first sodium-ion battery cell 10 is connected to the negative tab 13 of the second sodium-ion battery cell 10, and the first sodium-ion battery cell 10 is the one after the second sodium-ion battery cell 10.

[0046] By connecting the positive tab 11 and negative tab 13 of adjacent sodium-ion cells 10, series connection at the cell level can be achieved. By connecting multiple sodium-ion cells 10 in series within the sodium-ion battery 1000, the rated voltage of a single sodium-ion battery 1000 can be increased. This eliminates the need for further series connection of the sodium-ion batteries 1000, enabling power supply for applications requiring high operating voltages. It also saves the space required for connecting multiple sodium-ion batteries 1000 in series, thus reducing the size of the battery module.

[0047] In one embodiment, the sodium-ion battery 1000 includes a first cell 15, a second cell, and a third cell connected in sequence. The positive tab 11 of the first cell 15 is connected to the positive terminal 30 of the sodium-ion battery 1000; the positive tab 11 of the second cell is connected to the negative tab 13 of the first cell 15; the positive tab 11 of the third cell is connected to the negative tab 13 of the second cell; and the negative tab 13 of the third cell is connected to the negative terminal 50 of the sodium-ion battery 1000.

[0048] In addition, the sodium-ion battery 1000 also includes an aluminum-plastic film casing 70, which encloses the sodium-ion cell 10 to form the sodium-ion battery 1000. Both the positive terminal 30 and the negative terminal 50 pass through the aluminum-plastic film so that the electrical energy of the sodium-ion cell 10 can be transferred to the outside of the sodium-ion battery 1000.

[0049] Compared to connecting multiple sodium-ion batteries 1000 in series to increase the total voltage, connecting sodium-ion cells 10 in series inside the sodium-ion battery 1000 increases the rated voltage of a single sodium-ion battery 1000. This reduces the amount of aluminum-plastic film casing 70 and the positive and negative terminals 30 and 50 used, saving raw materials and production costs, and is also beneficial for energy conservation.

[0050] In this way, by connecting multiple sodium-ion cells 10 in series and supplying power externally through the positive terminal 30 and the negative terminal 50, a single sodium-ion battery 1000 can output a larger voltage to meet the needs of high-voltage applications. Furthermore, the series connection of cells within the single sodium-ion battery 1000 saves space during battery connections, resulting in high space utilization and high integration. It also helps reduce internal resistance and improve battery consistency.

[0051] Please see Figure 1 and Figure 2 In some embodiments, the positive tab 11 of the current sodium-ion battery cell 10 is welded to the negative tab 13 of the previous sodium-ion battery cell 10 by ultrasonic welding.

[0052] Specifically, in related technologies, the positive electrode material of lithium-ion batteries is aluminum foil, and the negative electrode material is copper foil. Since aluminum foil and copper foil cannot be directly welded together, a nickel strip is needed to weld the positive and negative electrodes of the two lithium-ion cells.

[0053] In this embodiment, the positive and negative tabs 13 of the sodium-ion cells 10 included in the sodium-ion battery 1000 are both made of aluminum foil. Therefore, the positive tabs 11 and negative tabs 13 of two adjacent sodium-ion cells 10 can be directly welded at the weld point 90 by ultrasonic welding. Compared with the method of using nickel strip to assist welding, ultrasonic welding is simpler, uses less material, and has a simpler structure. Furthermore, there is no need to reserve space for nickel strip, which is beneficial to further reduce the volume of the series-connected sodium-ion batteries 1000.

[0054] The current sodium-ion battery cell 10 can be any sodium-ion battery cell 10 other than the first cell 15 among multiple sodium-ion battery cells 10. The previous sodium-ion battery cell 10 is the sodium-ion battery cell 10 that is ranked first among multiple sodium-ion battery cells 10 connected in series, relative to the current sodium-ion battery cell 10. It can be seen that the last cell 17 will not be considered as the "previous sodium-ion battery cell 10".

[0055] Furthermore, the solder joint 90 can be selected at the middle position of the overlap between the positive electrode tab 11 and the negative electrode tab 13, so as to avoid being too close to the core body 19 and causing damage to the core body 19 during welding, and also to avoid being too far from the core body 19 and causing unstable welding.

[0056] In one embodiment, the sodium-ion battery 1000 includes a first cell 15, a second cell, and a third cell connected in sequence. The positive electrode 11 of the second cell is ultrasonically welded to the negative electrode 13 of the first cell 15, the positive electrode 11 of the third cell is ultrasonically welded to the negative electrode 13 of the second cell, and the negative electrode 13 of the third cell is ultrasonically welded to the negative terminal 50 of the sodium-ion battery 1000.

[0057] Thus, by connecting the positive electrode 11 of the current sodium-ion battery cell 10 with the negative electrode 13 of the previous sodium-ion battery cell 10 through ultrasonic welding, the process is simple and the connection structure is also simpler.

[0058] Please see Figures 4 to 6 In some embodiments, the sodium-ion battery cell 10 is formed by winding a core body 19, which includes a positive current collector 191, a diaphragm 193 and a negative current collector 195. The diaphragm 193 is disposed between the positive current collector 191 and the negative current collector 195. A portion of the positive current collector 191 forms a positive tab 11 and a portion of the negative current collector 195 forms a negative tab 13.

[0059] Specifically, the positive current collector 191, the diaphragm 193, and the negative electrode contactor of the core body 19 are stacked in sequence and wound to form a sodium-ion battery cell 10. The diaphragm 193 is used to isolate the positive current collector 191 and the negative current collector 195 to prevent short circuits caused by contact between the positive electrode contactor and the negative electrode current collector 195.

[0060] in, Figure 4 For along Figure 1 Looking at the sodium-ion battery 10 from direction A, the structure of the positive electrode current collector 191, the separator 193, and the negative electrode current collector 195 of the core 19 is shown. It should be noted that... Figure 4 The positive electrode 11 or negative electrode 13 is omitted.

[0061] Please see Figure 5 Part of the positive current collector 191 forms a positive tab 11, and part of the negative current collector 195 forms a negative tab 13. When the core body 19 is wound to form a sodium ion battery cell 10, the positive tab 11 and the negative tab 13 are exposed so as to facilitate connection with the outside of the sodium ion battery cell 10.

[0062] Further, please refer to Figure 6 After the core body 19 is rolled, the positive electrode tabs 11 formed by each turn of the positive current collector 191 are welded together to form the positive electrode tabs 11 of the core body 19. The negative electrode tabs 13 formed by each turn of the negative current collector 195 are welded together to form the negative electrode tabs 13 of the core body 19.

[0063] Figure 6 The positive electrode tabs 11 formed by each turn of the positive current collector 191 are welded together, and the common extension of the positive electrode tabs 13 formed by each turn of the negative current collector 195 is also welded together, and the common extension of the negative electrode tabs 13 is also welded together. The positive electrode tabs 11 and negative electrode tabs 13 of two adjacent sodium-ion cells 10 are ultrasonically welded at the weld points to achieve series connection.

[0064] In addition, each core 19 is rolled to form a sodium ion battery cell 10, and multiple sodium ion battery cells 10 are then welded together in series.

[0065] Thus, positive electrode tab 11 and negative electrode tab 13 can be formed through positive electrode current collector 191 and negative electrode current collector 195. A diaphragm 193 is provided between positive electrode current collector 191 and negative electrode current collector 195 to prevent short circuits inside the battery cell.

[0066] In some embodiments, the positive current collector 191 and the negative current collector 195 are made of aluminum foil.

[0067] Specifically, both the positive current collector 191 and the negative current collector 195 are made of aluminum foil, and part of the positive current collector 191 forms a positive tab 11, while part of the negative current collector 195 forms a negative tab 13, making the materials of the positive tab 11 and the negative tab 13 also aluminum foil. Since the positive tab 11 and the negative tab 13 are made of the same material, the positive tab 11 and the negative tab 13 of two adjacent sodium-ion cells 10 can be directly welded together by ultrasonic welding, thereby realizing the series connection of two adjacent sodium-ion cells 10.

[0068] Thus, the positive current collector 191 and the negative current collector 195 are made of aluminum foil, which allows the positive electrode tab 11 and the negative electrode tab 13 to be connected directly by welding.

[0069] In some embodiments, the diaphragm 193 is made of a microporous membrane.

[0070] Specifically, the separator 193 is a microporous membrane with high porosity and low resistance, so as to effectively isolate the positive current collector 191 and the negative current collector 195 while minimizing the impact on the performance of the sodium-ion battery cell 10. The microporous membrane can prevent short circuits and internal reactions between the positive current collector 191 and the negative current collector 195, thereby improving the stability of the sodium-ion battery cell 10.

[0071] Thus, by placing a microporous membrane between the positive electrode current collector 191 and the negative electrode current collector 195, the impact on the performance of the sodium-ion battery cell 10 can be reduced while isolating the positive electrode current collector 191 and the negative electrode current collector 195.

[0072] In some embodiments, a positive electrode material layer 1911 is partially coated on the surface of the positive current collector 191, and a negative electrode material layer 1951 is partially coated on the surface of the negative current collector 195.

[0073] Specifically, the positive electrode layer 1911 is made of positive electrode active material, and the negative electrode layer 1951 is made of negative electrode active material. Both the positive and negative electrode active materials can release and store sodium ions to achieve charging and discharging of the sodium-ion battery cell 10. During charging, sodium ions flow from the negative electrode to the positive electrode, and the positive electrode active material receives sodium ions and stores electrical energy. During discharging, sodium ions flow from the positive electrode to the negative electrode, and the positive electrode active material releases sodium ions, releasing electrical energy.

[0074] Coating the surface of the positive electrode current collector 191 with a positive electrode material layer 1911 can improve the adhesion between the positive electrode current collector 191 and the electrolyte 110, and can also prevent the positive electrode current collector 191 from over-dissolving.

[0075] Coating the surface of the negative electrode current collector 195 with a negative electrode material layer 1951 can prevent the electrolyte 110 from corroding the negative electrode current collector 195 and improve its service life. It can also increase the energy density of the battery cell and improve its performance.

[0076] Further, please refer to Figure 5 The positive current collector 191 and the negative current collector 195 do not completely overlap. The overlapping portions of the positive current collector 191 and the negative current collector 195 are coated with positive electrode material layer 1911 and negative electrode material layer 1951, respectively, while the non-overlapping portions are not coated to form positive electrode tab 11 and negative electrode tab 13.

[0077] Thus, coating the surface of the positive current collector 191 with a positive electrode material layer 1911 and the surface of the negative current collector 195 with a negative electrode material layer 1951 can improve the electrochemical capability of the current collector.

[0078] In some embodiments, the material of the positive electrode layer 1911 includes at least one of Prussian blue analogues, layered oxides, and polyanionic compounds.

[0079] Specifically, the positive electrode layer 1911 selects sodium-ion positive electrode materials with high specific capacity and high stability, such as Prussian blue analogues, layered oxides, polyanionic compounds, etc.

[0080] In some embodiments, the material of the negative electrode layer 1951 includes at least one of hard carbon and soft carbon.

[0081] Specifically, the negative electrode layer 1951 is selected from materials capable of reversibly inserting and de-inserting sodium ions, such as hard carbon or soft carbon. In one embodiment, the negative electrode layer 1951 is hard carbon. During charging, sodium ions migrate from the positive electrode to the negative electrode and insert into the hard carbon to form a sodium ion intercalation compound; during discharging, sodium ions de-inserte from the hard carbon and return to the positive electrode, while electrons flow from the negative electrode back to the external circuit, completing the discharge process.

[0082] In some embodiments, a positive electrode tab 11 is formed in the region of the positive electrode current collector 191 where the positive electrode material layer 1911 is not coated, and a negative electrode tab 13 is formed in the region of the negative electrode current collector 195 where the negative electrode material layer 1951 is not coated.

[0083] Specifically, a positive electrode material layer 1911 is partially coated on the positive current collector 191, and the portion without the positive electrode material layer 1911 forms a positive electrode tab 11. A negative electrode material layer 1951 is coated on the negative current collector 195, and the portion without the negative electrode material layer 1951 forms a negative electrode tab 13. This ensures that the aluminum foil at both the positive electrode tab 11 and the negative electrode tab 13 is directly exposed, allowing for direct soldering.

[0084] Thus, the positive electrode material layer 1911 or the negative electrode material layer 1951 is not coated in the positive electrode tab 11 and the negative electrode tab 13 region, so that the positive electrode tab 11 and the negative electrode tab 13 can be directly soldered.

[0085] In some embodiments, the cell directions of two adjacent sodium-ion cells 10 are opposite, with the cell direction being from the positive tab 11 to the negative tab 13 of the sodium-ion cell 10.

[0086] Specifically, the cell directions of two adjacent sodium-ion battery cells 10 are opposite, which allows multiple sodium-ion battery cells 10 to be arranged in an overlapping manner, reducing the length of the sodium-ion battery cells 10 connected in series and facilitating aluminum-plastic film wrapping. The cell direction is the direction from the positive tab 11 to the negative tab 13 of the sodium-ion battery cell 10. It should be noted that the opposite cell directions here refer to the angle between the two cell directions being greater than 90 degrees, not simply two directions on the same straight line.

[0087] Thus, the cell directions of two adjacent sodium-ion cells 10 are opposite, which can reduce the length of the sodium-ion cells 10 connected in series, and help to reduce the volume of the sodium-ion battery 1000.

[0088] Please see Figure 1 In some embodiments, the sodium-ion battery 1000 further includes an electrolyte 110, which may be a liquid electrolyte 110, a gel electrolyte 110, or a solid electrolyte 110.

[0089] Specifically, the sodium-ion cells 10 inside the sodium-ion battery 1000 are connected in series and then connected to the positive terminal 30 and the negative terminal 50. The sodium-ion cells 10 are then wrapped with an aluminum-plastic film to form the sodium-ion battery 1000. An electrolyte 110 is disposed within the aluminum-plastic film, and all sodium-ion cells 10 are immersed in the electrolyte 110. Furthermore, the electrolyte 110 is also present in the gaps between the positive current collector 191, the separator 193, and the negative current collector 195 of the sodium-ion cells 10.

[0090] In one embodiment, the electrolyte 110 is a liquid electrolyte 110. An injection hole is provided on the aluminum-plastic film to facilitate the injection of electrolyte into the sodium-ion battery 1000, so that the sodium-ion cell 10 is immersed in the electrolyte 110.

[0091] In some embodiments, the sodium-ion battery cell 10 further includes an insulating member 130, which surrounds the positive electrode tab 11 and the negative electrode tab 13 connected together, to prevent the interconnected positive and negative electrode tabs 13 of the internally connected sodium-ion battery cells 10 from contacting the electrolyte 110. The insulating member 130 includes insulating adhesive, etc.

[0092] Thus, the sodium-ion battery 1000 also includes an electrolyte 110 so that sodium ions can move in the electrolyte 110 to realize the charging and discharging function of the sodium-ion cell 10.

[0093] In some embodiments, when the sodium-ion cell 10 is a omnipolar cell, the positive terminal 30 and the negative terminal 50 are located at opposite ends of the sodium-ion battery 1000, and the number of sodium-ion cells 10 is odd.

[0094] Specifically, since positive tabs 11 and negative tabs 13 are evenly distributed at opposite ends of the all-tab cell, there is no space on the same side of the sodium-ion battery 1000 to simultaneously accommodate both positive tabs 11 and negative tabs 13. Therefore, when the sodium-ion cell 10 is an all-tab cell, the positive terminal 30 and the negative terminal 50 need to be located at opposite ends of the sodium-ion battery 1000 to provide space for the positive tabs 11 and negative tabs 13 respectively.

[0095] Furthermore, since the positive and negative tabs 13 of two adjacent cells are connected and placed in opposite directions, when the number of sodium-ion cells 10 is even, the total positive tab 11 and the total negative tab 13 of the series-connected sodium-ion cells 10 are on the same side, which does not meet the requirement that the positive and negative terminals 50 of a battery with full-tab cells should be opposite in direction. Therefore, when the sodium-ion cells 10 are full-tab cells, the number of sodium-ion cells 10 is odd.

[0096] In one embodiment, the sodium-ion battery cell 10 is a omnipolar battery cell, and the number of sodium-ion battery cells 10 is 3.

[0097] Thus, when the sodium-ion cell 10 is a multi-tab cell, the positive terminal 30 and the negative terminal 50 need to be located at opposite ends of the sodium-ion battery 1000 to provide space for the positive tab 11 and negative tab 13 of the sodium-ion cell 10. This also prevents the positive tab 11 and negative tab 13 of the sodium-ion cell 10 from short-circuiting after the electrolyte 110 is injected. Furthermore, the number of sodium-ion cells 10 is odd, so that the total positive tab 11 and total negative tab 13 of the multiple sodium-ion cells 10 connected in series are located at opposite ends.

[0098] In one embodiment, the sodium-ion battery 1000 includes three sodium-ion cells 10, with adjacent sodium-ion cells 10 connected together by ultrasonic welding via positive tabs 11 and negative tabs 13. Each sodium-ion cell 10 has a positive electrode current collector 191 coated with a positive electrode material layer 1911 (NaFePO4) and a negative electrode current collector 195 coated with a negative electrode material layer 1951 (hard carbon). The separator 193 between the positive electrode current collector 191 and the negative electrode current collector 195 is a PE single-sided ceramic separator 193. The voltage range of each sodium-ion cell 10 is 1.5V to 3.45V.

[0099] Please see Figure 7 The capacity retention rates of the internally connected sodium-ion battery 1000 and the conventional externally connected sodium-ion battery 1000 under a continuous discharge rate of 60C are shown in the figure. It can be seen that the internally connected sodium-ion battery 1000 has a higher capacity retention rate.

[0100] This utility model provides an electrical device, which includes a sodium-ion battery 1000 as described in any of the above embodiments.

[0101] In the description of this specification, the terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with an embodiment or example that are included in at least one embodiment or example of this utility model. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0102] Furthermore, the term "connection" should be interpreted broadly. For example, it can include a fixed connection, a detachable connection, or an integral connection; it can include a direct connection or an indirect connection through an intermediate medium; and it can also include communication between the internal components of two elements. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0103] 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 indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this utility model, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0104] Any process or method described in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or more executable instructions for implementing a particular logical function or process, and the scope of the preferred embodiments of the present invention includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order according to the functions involved, as should be understood by those skilled in the art to which embodiments of the present invention pertain.

[0105] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A sodium-ion battery, characterized in that, The sodium ion battery comprises a plurality of series-connected sodium ion cells, a positive electrode terminal and a negative electrode terminal, wherein, in the plurality of sodium ion cells, a positive electrode tab of a first cell arranged at the first position is connected to the positive electrode terminal, positive electrode tabs of sodium ion cells other than the first cell are sequentially connected to negative electrode tabs of previous sodium ion cells, and a negative electrode tab of the last sodium ion cell arranged at the last position is connected to the negative electrode terminal.

2. The sodium-ion battery of claim 1, wherein, The positive electrode tab of the current sodium ion cell and the negative electrode tab of the previous sodium ion cell are welded by ultrasonic welding.

3. The sodium-ion battery of claim 1, wherein, The sodium ion cell is formed by rolling a roll core, which comprises a positive electrode current collector, a separator and a negative electrode current collector, the separator being arranged between the positive electrode current collector and the negative electrode current collector, part of the positive electrode current collector forming the positive electrode tab, and part of the negative electrode current collector forming the negative electrode tab.

4. The sodium-ion battery of claim 3, wherein, The positive electrode current collector and the negative electrode current collector are made of aluminum foil.

5. The sodium-ion battery of claim 3, wherein, The separator is made of a microporous membrane.

6. The sodium-ion battery of claim 3, wherein, The positive electrode current collector is partially coated with a positive electrode material layer, and the negative electrode current collector is partially coated with a negative electrode material layer.

7. The sodium-ion battery of claim 6, wherein, The positive electrode tab is formed in an area of the positive electrode current collector where the positive electrode material layer is not coated, and the negative electrode tab is formed in an area of the negative electrode current collector where the negative electrode material layer is not coated.

8. The sodium-ion battery of claim 6, wherein, The material of the positive electrode material layer comprises at least any one of Prussian blue analogues, layered oxides and polyanionic compounds.

9. The sodium-ion battery of claim 6, wherein, The material of the negative electrode material layer comprises at least any one of hard carbon and soft carbon.

10. The sodium-ion battery of claim 1, wherein, The cell direction of two adjacent sodium ion cells is opposite, and the cell direction is a direction from the positive electrode tab to the negative electrode tab of the sodium ion cell.

11. The sodium-ion battery of claim 1, wherein, The sodium ion battery further comprises an electrolyte, and the electrolyte comprises a liquid electrolyte, a gel electrolyte or a solid-state electrolyte.

12. The sodium-ion battery of claim 1, wherein, When the sodium ion cell is a full-tab cell, the positive electrode terminal and the negative electrode terminal are arranged at opposite ends of the sodium ion battery, and the number of sodium ion cells is odd.

13. An electrical device, characterized by The electric device comprises the sodium ion battery according to any one of claims 1-12.

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