Pole piece, preparation method thereof, battery cell module, battery pack and electric equipment

Abstract

The application provides a pole piece and a preparation method thereof, a battery cell module, a battery pack and a power utilization device, and relates to the technical field of energy storage devices. The pole piece comprises a current collector, a positive active layer and a negative active layer. The current collector comprises a first surface and a second surface opposite in the thickness direction; the positive active layer is arranged on the first surface, and the positive active layer comprises positive active material, wherein the positive active material comprises lithium-based active material and sodium-based active material; and the negative active layer is arranged on the second surface. The pole piece provided by the application can be applied between adjacent battery cells. When adjacent battery cells perform current transmission, the positive active layer of one of the battery cells transmits current to the current collector thereof, and then the current is directly transmitted to the negative active layer of the adjacent battery cell through the current collector, thereby reducing the number of connecting lines between adjacent battery cells, reducing the complexity and failure rate of the battery pack, and improving the integration degree of the battery pack.

Description

Technical Field

[0001] This invention relates to the field of energy storage technology, and in particular to an electrode sheet and its preparation method, a cell module, a battery pack, and electrical equipment. Background Technology

[0002] A battery cell is a basic component of a battery, typically an electrochemical device encapsulated in a metal casing or aluminum-plastic film.

[0003] Existing battery cells include a positive electrode and a negative electrode. The positive and negative electrode each include a positive current collector and a negative current collector, respectively. The positive current collector is located on the positive side of the battery, in contact with the positive active material, collecting the current generated at the positive electrode and transferring it to the positive terminal. The negative current collector is located on the negative side of the battery, in contact with the negative active material, collecting the current generated at the negative electrode and transferring it to the negative terminal. In a battery cell module, the terminals of multiple cells can be connected in series or parallel via connecting wires.

[0004] However, battery modules are often composed of multiple battery cells, resulting in a large number of connecting wires and other components, lower integration of the battery pack, and an increased failure rate. Summary of the Invention

[0005] In view of the above problems, this application provides an electrode sheet and its preparation method, a cell module, a battery pack, and an electrical device to solve the problems of existing cell modules having many components, low integration, and high battery pack failure rate.

[0006] In a first aspect, this application provides an electrode sheet, comprising:

[0007] The current collector includes a first surface and a second surface that are opposite each other along the thickness direction;

[0008] A positive electrode active layer is disposed on the first surface, the positive electrode active layer includes a positive electrode active material, the positive electrode active material includes a lithium-based active material and a sodium-based active material;

[0009] The negative electrode active layer is disposed on the second surface.

[0010] In the battery cell module, the electrode sheets of this embodiment can be applied between adjacent cells to form an efficient current transmission path. When adjacent cells transmit current, the positive electrode active layer of one cell transmits the current to its current collector, and then the current is transmitted through the current collector to the negative electrode active layer of the adjacent cell. Compared to traditional battery cell modules where multiple cells are connected in series or parallel via connecting wires, the electrode sheets of this embodiment can be directly applied between adjacent cells to form an efficient current transmission path, reducing the number of connecting wires, lowering the complexity and failure rate of the battery pack, and also achieving an increase in battery pack density within a limited space, thus improving the integration of the battery pack.

[0011] In one possible implementation, the lithium-based active material includes at least one of lithium iron phosphate, lithium nickel cobalt manganese oxide, lithium manganese oxide, lithium cobalt oxide, and lithium manganese iron phosphate.

[0012] In one possible implementation, the sodium-based active material includes at least one of layered structures, Prussian blue analog cathodes, and polyanionic types.

[0013] In one possible implementation, the molar ratio of lithium to sodium in the positive electrode active material ranges from 0.1 to 50.

[0014] The ratio of lithium to sodium can affect the electrochemical activity, energy density, cycle stability, and cost-effectiveness of hybrid cathode materials. For example, a lower lithium ratio (e.g., close to 0.1%) means that sodium dominates the material, which may bring a cost advantage because sodium resources are relatively abundant and inexpensive. A higher lithium ratio (e.g., close to 50%) may improve the energy density and electrochemical performance of the material, but correspondingly, the cost will also increase. By reasonably adjusting the lithium-sodium ratio, the cost-effectiveness of the lithium-sodium mixture can be optimized while maintaining certain electrochemical performance.

[0015] In one possible implementation, the positive electrode active material further includes aluminum oxide.

[0016] Alumina coating can inhibit the adsorption of water molecules by the material and improve surface stability. Furthermore, it is understandable that when the battery is charged to a high voltage, transition metal ions (such as Co) in the positive electrode material... 3+ ) may change (e.g., become Co) 4 + This leads to oxygen vacancies and structural weakening. Applying an aluminum oxide coating can reduce these structural changes and improve the material's structural stability. Furthermore, the aluminum oxide coating can improve the ionic and electronic conductivity of the cathode material, thereby improving its electrochemical performance, such as specific capacity, cycle stability, and rate capability. Additionally, the aluminum oxide coating avoids direct contact between the lithium-sodium mixture and the electrolyte, reducing electrochemical side reactions and capacity loss. Aluminum oxide also possesses good thermal stability and can be used as a heat insulation layer to improve the stability of the cathode material at high temperatures.

[0017] In one possible implementation, the aluminum oxide accounts for 0.1%-5% of the positive electrode active layer by mass percentage.

[0018] In one possible implementation, the positive electrode active material further includes a dopant element, including titanium.

[0019] Titanium doping can lower the migration barrier of sodium ions, improve the electrochemical performance of cathode materials, optimize the electronic structure and ion transport channels, enhance ionic and electronic conductivity, and improve the high-rate charge-discharge capability, thus benefiting battery performance. Furthermore, it can enhance the structural stability of the cathode active layer. By occupying some lattice sites, titanium can stabilize the crystal structure of the material, reducing potential structural changes during charge-discharge processes, thereby improving battery cycle stability and lifespan.

[0020] In one possible implementation, the molar percentage of titanium in the positive electrode active material is 0.1%-5%.

[0021] In one possible implementation, the current collector is a copper-aluminum composite current collector.

[0022] The polymer insulating material in the middle layer of the copper-aluminum composite current collector is not easily broken and has strong puncture resistance, which can prevent short circuits within the battery and avoid thermal runaway and spontaneous combustion caused by short circuits. In addition, the middle layer material can be made of lighter materials such as PET and PP, reducing the battery weight and thus maintaining or increasing the battery capacity and energy density. Furthermore, the cost of the middle layer is lower than that of copper / aluminum metal, giving this copper-aluminum composite current collector a cost advantage. Moreover, the copper-aluminum composite current collector also has good corrosion resistance and high-temperature resistance, reducing structural changes that may occur during charge and discharge, and improving the battery's cycle stability and lifespan.

[0023] Secondly, this application provides a method for preparing an electrode sheet, used to prepare the electrode sheet in one of the above possible implementations, comprising the following steps:

[0024] The lithium source and sodium source are mixed and then ground.

[0025] The ground powder is then dried.

[0026] The powder is sintered at high temperature to obtain a positive electrode material;

[0027] The cathode material was doped with aluminum oxide and then ground.

[0028] In one possible implementation, the grinding of the lithium source and sodium source after mixing includes adding titanium to the lithium source and the sodium source.

[0029] Thirdly, this application also provides a battery cell module, including:

[0030] In any of the above possible implementations, the electrodes are arranged in a stacked manner;

[0031] Two unipolar electrodes are respectively disposed at both ends of the plurality of electrodes. Each unipolar electrode includes a current collector and an active layer located on one side of the current collector, the active layer being located on the side of the current collector facing the electrode.

[0032] A diaphragm is disposed between two adjacent electrodes and between adjacent electrodes and the unipolar electrode.

[0033] As can be seen, the design of the battery cell module allows the positive electrode active layer of one cell to directly transmit current to its current collector, and then this current is directly transmitted through the current collector to the negative electrode active layer of the adjacent cell. This reduces losses during current transmission and improves the overall efficiency of the battery cell module. Furthermore, it increases the density of the battery pack within a limited space, reduces the number of connecting wires, and improves the integration of the battery pack.

[0034] Fourthly, this application also provides a battery pack, comprising:

[0035] case;

[0036] In any of the above possible implementations, the battery cell module is a plurality of cells arranged in a stacked manner;

[0037] A phase change composite plate is sandwiched between two adjacent battery cell modules;

[0038] The thermal insulation composite board comprises two panels, one of which is disposed on the top of the plurality of battery cell modules, and the other of which is disposed on the bottom of the plurality of battery cell modules.

[0039] The synergistic effect of the phase change composite plate and the thermal insulation composite plate helps to keep the battery cell module within a suitable operating temperature range, prevents safety issues such as overheating and short circuits, and improves the performance and safety of the battery pack.

[0040] In one possible implementation, the phase change composite plate includes:

[0041] First phase change layer;

[0042] The first thermal conductive layer consists of two layers, which are located on opposite sides of the first phase change layer.

[0043] When the temperature of the battery cell module rises, the first thermally conductive layer can transfer heat to the first phase change layer. The first phase change layer then absorbs this heat by undergoing a phase change, thereby reducing the temperature of the battery cell module. In this way, the battery pack can maintain a lower temperature when operating under high load, improving the performance and safety of the battery pack.

[0044] In one possible implementation, the thermal insulation composite panel includes:

[0045] Second phase change layer;

[0046] The second thermally conductive layer is disposed on the side of the second phase change layer facing the cell module;

[0047] A thermal insulation layer is disposed on the side of the second phase change layer opposite to the battery cell module.

[0048] Through the synergistic effect of the second phase change layer and the second thermal conductive layer, the battery pack can dissipate heat when the temperature of the cell module rises and maintain the stability of the internal temperature when the temperature of the cell module falls. In addition, the thermal insulation layer can further reduce the heat exchange between the inside of the battery pack and the external environment, and improve the thermal insulation effect of the battery pack.

[0049] Fifthly, this application also provides an electrical device including the battery pack described in any of the above possible implementations.

[0050] This application provides an electrode sheet and its preparation method, a cell module, a battery pack, and an electrical device. The electrode sheet provided in this application can be applied between adjacent cells to form an efficient current transmission path. When adjacent cells transmit signals, the positive electrode active layer of one cell transmits current to its current collector, and then the current is directly transmitted to the negative electrode active layer of the adjacent cell through the current collector. Compared to traditional cell modules where multiple cells are connected in series or parallel via connecting wires, the electrode sheet of this application can be directly applied between adjacent cells to form an efficient current transmission path, reducing the number of connecting wires, lowering the complexity and failure rate of the battery pack, and also achieving an increase in battery pack density within a limited space, thus improving the integration of the battery pack. Attached Figure Description

[0051] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0052] Figure 1 This is a schematic diagram of the battery cell structure of the present invention;

[0053] Figure 2 This is a schematic diagram of the battery cell module of the present invention;

[0054] Figure 3 This is a schematic diagram of the battery pack structure of the present invention;

[0055] Figure 4 This is an exploded view of the battery pack of the present invention;

[0056] Figure 5 for Figure 4 A schematic diagram of the phase change composite plate in the diagram;

[0057] Figure 6 for Figure 4 Schematic diagram of the structure of the thermal insulation composite panel;

[0058] Figure 7 This is a flowchart of the method for preparing the electrode sheet of the present invention;

[0059] Figure 8 This is a schematic diagram of the battery cell module cycling at -10℃.

[0060] Explanation of reference numerals in the attached figures:

[0061] 100 - Electrode; 110 - Current collector; 111 - First surface; 112 - Second surface; 120 - Positive electrode active layer; 130 - Negative electrode active layer;

[0062] 200-cell;

[0063] 300 - Cell module; 310 - Unipolar electrode; 320 - Separator; 330 - Electrolyte; 340 - Sealing component;

[0064] 400 - Battery pack; 410 - Phase change composite plate; 411 - First phase change layer; 412 - First thermally conductive layer; 420 - Thermal insulation composite plate; 421 - Second phase change layer; 422 - Second thermally conductive layer; 423 - Thermal insulation layer. Detailed Implementation

[0065] To make the above-mentioned objectives, features, and advantages of the embodiments of this application more apparent and understandable, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0066] A battery cell is the basic component of a battery, typically an electrochemical device encapsulated in a metal casing or aluminum-plastic film. A battery cell mainly consists of a positive electrode, a negative electrode, a separator, an electrolyte, and a casing. The positive and negative electrodes are separated by the separator. Through chemical reactions, chemical energy is converted into electrical energy, enabling the storage and release of electrical energy. Battery cells are placed vertically on a tray, and multiple cells are connected one after another. Heating films and cooling plates are then placed on the sides of the cells to form a battery pack.

[0067] Specifically, existing battery cells include a positive electrode and a negative electrode. The positive and negative electrode each include a positive current collector and a negative current collector, respectively. The positive current collector is located on the positive side of the battery, in contact with the positive active material, collecting the current generated at the positive electrode and transmitting it to the positive terminal. The negative current collector is located on the negative side of the battery, in contact with the negative active material, collecting the current generated at the negative electrode and transmitting it to the negative terminal. In a battery cell module, the terminals of multiple cells can be connected in series or parallel via connecting wires.

[0068] However, battery modules are often composed of multiple battery cells, resulting in a large number of connecting wires and other components, lower integration of the battery pack, and an increased failure rate.

[0069] In some situations, such as low-temperature environments, the viscosity of the electrolyte inside the battery will increase, the battery impedance will increase, and the electrochemical reaction rate will slow down, resulting in a decrease in the battery's output power and charge / discharge capacity.

[0070] In addition, the heating film and cold plate are in contact with the side of the battery cell. However, the side area of ​​the battery cell is small, which can lead to poor heat conduction when the heating film and cold plate are working.

[0071] In addition, the close contact distance between adjacent cells leads to severe heat conduction between cells, affecting the reliability of the battery pack.

[0072] In view of this, this application provides an electrode sheet and its preparation method, a cell module, a battery pack, and an electrical device. The electrode sheet provided in this application can be applied between adjacent cells to form an efficient current transmission path. When adjacent cells transmit current, the positive electrode active layer of one cell transmits the current to its current collector, and then the current is directly transmitted to the negative electrode active layer of the adjacent cell through the current collector. Compared with traditional cell modules where multiple cells are connected in series or parallel through connecting wires, the electrode sheet of this application embodiment can be directly applied between adjacent cells to form an efficient current transmission path, reducing the number of connecting wires, reducing the complexity and failure rate of the battery pack, and also achieving an increase in battery pack density within a limited space, thus improving the integration of the battery pack.

[0073] The following is for reference. Figures 1-8 The electrode 100 according to an embodiment of this application is described.

[0074] refer to Figures 1-3 The electrode 100 of this embodiment can be applied to a battery cell. Specifically, the electrode 100 may include a current collector 110, a positive electrode active layer 120, and a negative electrode active layer 130.

[0075] The current collector 110 includes a first surface 111 and a second surface 112 that are opposite each other along the thickness direction. The main function of the current collector 110 is to carry the active material (i.e., the positive electrode active layer 120 and the negative electrode active layer 130) and collect and output the current generated by the active material during charging and discharging, or input the current to the active material.

[0076] A positive electrode active layer 120 is disposed on the first surface 111. The positive electrode active layer 120 includes a positive electrode active material, which includes a lithium-based active material and a sodium-based active material. The lithium-based active material usually has a high energy density, and the sodium-based active material has good ion conductivity at low temperatures. This lithium-sodium mixture is suitable for improving the electrochemical reaction rate and current collection efficiency of the battery in low-temperature environments.

[0077] Optionally, the positive electrode active material can also be either a lithium-based active material or a sodium-based active material.

[0078] A negative electrode active layer 130 is disposed on the second surface 112. The negative electrode active layer 130 is responsible for reacting with lithium ions in the electrolyte during charging and discharging to store and release electrical energy. For example, the material of the negative electrode active layer 130 may be graphite or lithium titanium oxide, etc.

[0079] In other words, the electrode 100 in this embodiment is a bipolar electrode. When the electrode 100 is applied in a battery module in which multiple battery cells are stacked, the positive active layer 120 of the electrode 100 is actually equivalent to the positive electrode of one of the two adjacent battery cells, and the negative active layer 130 of the electrode 100 is actually equivalent to the negative electrode of the other of the two adjacent battery cells. The two battery cells to which the positive active layer 120 and the negative active layer 130 belong are electrically connected, such as in series, through the current collector 110 of the electrode 100.

[0080] In the battery cell module, the electrode 100 of this embodiment can be applied between adjacent battery cells to form an efficient current transmission path. When adjacent battery cells transmit current, the positive electrode active layer 120 of one battery cell transmits the current to its current collector 110, and then the current is directly transmitted through the current collector 110 to the negative electrode active layer 130 of the adjacent battery cell. Furthermore, since the current collector 110 has a large area, the resistance between the two adjacent battery cells can be reduced, which is beneficial for reducing heat generation.

[0081] Understandably, compared to the traditional battery cell module where multiple cells are connected in series or parallel via connecting wires, the electrode 100 of this application embodiment can be directly applied between adjacent cells to form an efficient current transmission path, reducing the number of connecting wires, reducing the complexity and failure rate of the battery pack 400, and also achieving an increase in the density of the battery pack 400 within a limited space, thereby improving the integration of the battery pack 400.

[0082] In addition, in some situations, such as low-temperature environments, the output power and charge / discharge capacity of the battery are improved by increasing the current transfer efficiency between adjacent cells, thus ensuring the battery's output.

[0083] Optionally, the material of the negative electrode active layer 130 can be graphite, silicon-based material, metal oxide, etc.

[0084] In some embodiments, the lithium-based active material includes at least one of lithium iron phosphate (LFP), lithium nickel cobalt manganese oxide (NCM), lithium manganese oxide (LMO), lithium cobalt oxide (LCO), and lithium manganese iron phosphate.

[0085] Specifically, lithium iron phosphate (LFP) is a polycrystalline material whose crystal structure consists of alternating lithium ions and phosphate ions forming a layered structure. LFP has high specific capacity and energy density, stable voltage, and does not require equalization charging during charging, thus extending battery life.

[0086] Lithium nickel cobalt manganese oxide (NCM) is a ternary cathode material for lithium-ion batteries, featuring high energy density, good cycle stability, high voltage plateau, and good thermal stability.

[0087] Lithium manganese oxide (LMO) offers advantages such as low cost, high potential, environmental friendliness, and high safety. Furthermore, spinel-type lithium manganese oxide exhibits a stable structure, is easy to industrialize, and demonstrates good rate performance and stability. Lithium manganese oxide can be used in low-power power batteries and energy storage batteries, as well as as a cathode material for lithium-ion batteries in portable electronic devices.

[0088] Lithium cobalt oxide (LCO) possesses high specific capacity, high operating voltage, and good cycle stability, making it suitable for use in small electronic products such as mobile phones and laptops. Additionally, lithium iron manganese phosphate can also be used as a cathode material in lithium-ion batteries, showing promising application prospects.

[0089] The lithium-based active materials mentioned above all have certain characteristics and advantages, and can be selected according to actual needs, without any restrictions.

[0090] In some embodiments, the sodium-based active material includes at least one of layered structures, Prussian blue analog cathodes, and polyanionic types.

[0091] For example, layered structures such as layered NaxTMO2 (Me = transition metal, such as Fe, Cr, Co, Mn, Ni, V, Cu and mixtures thereof) oxides have large specific capacity and reversible intercalation / deintercalation characteristics.

[0092] Furthermore, Prussian blue (PB) and its analogues (PBAs) are composed of a three-dimensional framework structure, providing a wide channel for the insertion and extraction of sodium ions. Polyanionic compounds are compounds with a three-dimensional network structure formed by strong covalent bonds between polyanionic polyhedra and transition metal ion polyhedra, giving them high chemical stability, thermal stability, and electrochemical stability.

[0093] In some embodiments, the molar ratio of lithium to sodium in the positive electrode active material ranges from 0.1 to 50. For example, the molar ratio of lithium to sodium can be 0.1, 0.2, 0.5, 0.8, 1, 2, 5, 10, 12, 20, 26, 34, 42, or 50. Of course, this application does not limit this, and the molar ratio of lithium to sodium can be reasonably selected within the above range according to actual needs.

[0094] Understandably, mixing lithium-based and sodium-based active materials forms a lithium-sodium mixture. The ratio of lithium to sodium in this mixture can affect the electrochemical activity, energy density, cycle stability, and cost-effectiveness of the hybrid cathode material. For example, a lower lithium ratio (e.g., close to 0.1%) means that sodium is dominant in the material, which may bring a cost advantage because sodium resources are relatively abundant and inexpensive. A higher lithium ratio (e.g., close to 50%) may improve the energy density and electrochemical performance of the material, but correspondingly, the cost will also increase. By reasonably adjusting the ratio of lithium and sodium, the lithium-sodium mixture can maintain certain electrochemical performance while optimizing cost-effectiveness.

[0095] In some embodiments, refer to Figure 1 The positive electrode active material also includes aluminum oxide. Aluminum oxide coating can inhibit the adsorption of water molecules and improve surface stability.

[0096] Furthermore, it is understandable that when the battery is charged to a high voltage, transition metal ions (such as Co) in the positive electrode material... 3+ ) may change (e.g., become Co) 4+ This leads to the formation of oxygen vacancies and structural weakening. Applying an aluminum oxide coating can reduce these structural changes and improve the material's structural stability. Furthermore, the aluminum oxide coating can improve the ionic and electronic conductivity of the cathode material, thereby enhancing its electrochemical performance, such as specific capacity, cycle stability, and rate capability.

[0097] In addition, the aluminum oxide coating avoids direct contact between the lithium-sodium mixture and the electrolyte, reducing electrochemical side reactions and capacity loss. Aluminum oxide also exhibits good thermal stability and can be used as a heat insulation layer to improve the stability of the cathode material at high temperatures.

[0098] For example, the aluminum oxide coating can be formed by chemical synthesis, physical coating, and other methods. Specifically, the aluminum oxide coating can be prepared by chemical synthesis methods, such as the sol-gel method and co-precipitation method; or by physical coating methods such as spray drying and blade coating, aluminum oxide powder can be coated onto the surface of a lithium-sodium mixture.

[0099] In some embodiments, the proportion of aluminum oxide in the positive electrode active material is 0.1%-5% by mass. For example, the proportion of aluminum oxide in the positive electrode active layer 120 can be 0.1%, 0.2%, 0.4%, 1%, 1.5%, 2.2%, 3.4%, 4.7%, or 5%. Of course, the embodiments of this application do not limit this, and the proportion of aluminum oxide in the positive electrode active layer 120 can be reasonably selected within the above range according to actual needs.

[0100] Furthermore, in practical applications, experiments and tests can be conducted to determine the optimal ratio of aluminum oxide in the positive electrode active layer 120. This ratio can achieve certain advantages in terms of structural stability, electrochemical performance, thermal stability, and cost-effectiveness, balancing battery performance and cost to achieve the best cost-performance ratio.

[0101] Alternatively, in addition to aluminum oxide, other coating materials such as carbon materials and silicates can also be used.

[0102] In some embodiments, the positive electrode active material further includes a dopant element, including titanium. Titanium doping can lower the migration barrier of sodium ions, improve the electrochemical performance of the positive electrode active material, optimize the electronic structure and ion transport channels of the material, enhance the ionic and electronic conductivity of the material, and improve the material's high-rate charge-discharge capability, thus benefiting the battery's performance.

[0103] Furthermore, it can enhance the structural stability of the positive electrode active layer 120. By occupying some lattice positions, titanium can stabilize the crystal structure of the material, reduce structural changes that may occur during charging and discharging, thereby improving the cycle stability and lifespan of the battery.

[0104] Alternatively, the preparation method for the dopant element can be co-precipitation, solid-phase sol-gel method, etc., and the specific method can be selected according to the actual situation, without any restrictions.

[0105] In some embodiments, the molar percentage of titanium in the positive electrode active material is 0.1%-5%. For example, the molar percentage of titanium in the positive electrode active material can be 0.1%, 0.2%, 0.4%, 1%, 1.5%, 2.2%, 3.4%, 4.7%, or 5%. Of course, the embodiments of this application do not limit this, and the molar percentage of titanium in the transition metal can be reasonably selected within the above range according to actual needs.

[0106] Specifically, in practical applications, experiments and tests can be conducted to determine the optimal doping ratio of titanium in the positive electrode active material, thereby balancing battery performance and cost and achieving the best cost-effectiveness.

[0107] In some embodiments, refer to Figure 1 and Figure 2 The current collector 110 is a copper-aluminum composite current collector. For example, the copper-aluminum composite current collector refers to a battery current collector 110 material with a polymer material as the intermediate layer and copper and aluminum plating on both sides, respectively. Optionally, the intermediate layer can be made of polymer materials such as polyethylene terephthalate (PET) or polypropylene (PP), with a layer of copper and aluminum plating on each side. For example, the thickness of the copper and aluminum plating can be selected as 1 micrometer. Alternatively, the current collector 110 includes a copper foil, an aluminum foil, and an intermediate layer, wherein the negative electrode active layer 130 is coated on the surface of the copper foil, the positive electrode active layer 120 is coated on the surface of the aluminum foil, and the copper foil and aluminum foil are compositely connected by the intermediate layer. For example, a polymer material can be used as the intermediate layer. Optionally, the intermediate layer can be made of polymer materials such as polyethylene terephthalate (PET) or polypropylene (PP), with a layer of copper and aluminum plating on each side. For example, the thickness of the copper and aluminum foil can be selected as 1 micrometer.

[0108] The polymer insulating material in the intermediate layer of the copper-aluminum composite current collector is not easily broken and has strong puncture resistance, which can prevent short circuits within the battery and prevent thermal runaway and spontaneous combustion caused by short circuits. In addition, the intermediate layer material can be made of lighter materials such as PET and PP to reduce the weight of the battery, thereby maintaining or increasing the battery capacity and improving the battery's energy density.

[0109] Furthermore, the intermediate layer is less expensive than copper / aluminum metal, giving this copper-aluminum composite current collector a cost advantage. In addition, the copper-aluminum composite current collector exhibits good corrosion resistance and high-temperature resistance, reducing potential structural changes during charge and discharge, and improving battery cycle stability and lifespan.

[0110] In addition, in some embodiments, a method for preparing the electrode 100 is also provided, for preparing the electrode 100 of any of the above embodiments, referring to... Figure 7 This includes the following steps:

[0111] S1. Mix the lithium source and sodium source and then grind them. Specifically, mix the lithium source and sodium source, place them in a ball mill jar, add solvent, and then ball mill.

[0112] S2. Dry the ground powder. Specifically, the ground powder is evenly dispersed and then vacuum dried.

[0113] S3. The powder is sintered at high temperature to obtain the cathode material. Specifically, after sintering, a lithium / sodium titanium sintered cathode material is obtained.

[0114] S4. The cathode material is doped with aluminum oxide and ground to obtain a composite cathode material.

[0115] In some embodiments, the lithium source and sodium source are mixed and then milled, including the addition of titanium to the lithium source and sodium source. Specifically, in S1, the lithium source and sodium source are mixed and then added to a ball mill jar along with titanium (Ti), and a solvent is added for ball milling.

[0116] It should be noted that lithium and sodium sources can be ground and sintered without the addition of titanium, and then doped and ground with Al2O3; lithium and sodium sources can also be ground and sintered with titanium without the addition of Al2O3 to obtain composite cathode materials.

[0117] The positive electrode is measured and coated on the surface of the bipolar positive electrode by mass percentage. The lithium / sodium-titanium-Al2O3 positive electrode composite active material accounts for 30% to 98% by mass percentage, the binder accounts for 0.5% to 5%, and the conductive agent accounts for 0.2% to 5%.

[0118] The active material of the battery's negative electrode is hard carbon. The active material is measured and coated onto the surface of the bipolar negative electrode by mass percentage, wherein the active material accounts for 30%–98% by mass, the binder accounts for 0.5%–5%, and the conductive agent accounts for 0.2%–5%.

[0119] Electrolyte 330 can be an electrolyte, a gel electrolyte 330, or a solid electrolyte 330. Electrolyte 330 can be one of lithium salt or sodium salt. The lithium salt can be one or more of lithium hexafluorophosphate, lithium tetrafluoroborate, and lithium perchlorate. The sodium salt can be one or more of sodium perchlorate, sodium hexafluorophosphate, and sodium tetrafluoroborate.

[0120] Sodium-ion batteries offer advantages such as excellent low-temperature performance, while lithium-ion batteries boast high specific energy and long cycle life. Doping the cathode material with titanium and coating it with aluminum oxide further enhances surface stability, resulting in superior cycle performance. Using lithium salts, sodium salts, and doping with titanium and coating with aluminum oxide in the cathode active material effectively improves the low-temperature discharge energy efficiency and cycle life of the battery cell.

[0121] Specifically, please refer to Example 1 and Comparative Examples 1-8 below. In conjunction with Table 1, the performance of the positive electrode active layer 120 was compared and tested by changing the composition ratio of the positive electrode active layer 120.

[0122] Example 1

[0123] The positive electrode active materials, lithium source and sodium source, were ground and sintered to prepare a composite positive electrode active layer 120 material. This composite material was then mixed with a conductive agent and binder and coated onto the positive electrode surface. Simultaneously, the negative electrode active material was mixed with a conductive agent and binder and coated onto the negative electrode surface. Following this, processes such as rolling, die-cutting, slitting, stacking, assembly, electrolyte injection, and formation were performed. The prepared battery was then subjected to a 1C / 1C charge-discharge cycle test at -10℃ to examine the capacity retention rate after 50 cycles (discharge capacity at cycle 50 / discharge capacity at cycle 1).

[0124] Comparative Example 1: The difference between Comparative Example 1 and Example 1 is that the proportion of Ti doped in the transition metal is 0.3% in Comparative Example 1, while all other aspects are the same as in Example 1.

[0125] Comparative Example 2: The difference between Comparative Example 2 and Example 1 is that the proportion of Ti doped in the transition metal is 1%, while all other aspects are the same as in Example 1.

[0126] Comparative Example 3: The difference between Comparative Example 3 and Example 1 is that the proportion of Ti doped in the transition metal is 3% in Comparative Example 3, while the rest are the same as in Example 1.

[0127] Comparative Example 4: The difference between Comparative Example 4 and Example 1 is that the proportion of Al2O3 added to the positive electrode in the active material is 0.3% by mass, while all other aspects are the same as in Example 1.

[0128] Comparative Example 5: The difference between Comparative Example 5 and Example 1 is that the proportion of Al2O3 added to the positive electrode in the active material is 1% by mass, while all other aspects are the same as in Example 1.

[0129] Comparative Example 6: The difference between Comparative Example 6 and Example 1 is that the proportion of Al2O3 added to the positive electrode in the active material is 3% by mass, while all other aspects are the same as in Example 1.

[0130] Comparative Example 7: The difference between Comparative Example 7 and Example 1 is that the proportion of Ti doped in the transition metal is 1%, and the proportion of Al2O3 added to the active material is 1%. All other aspects are the same as in Example 1.

[0131] Comparative Example 8: The difference between Comparative Example 8 and Example 1 is that the proportion of Ti doped in the transition metal is 1%, the proportion of Al2O3 added to the active material is 1%, and the test temperature is 25°C. All other aspects are the same as in Example 1.

[0132] Table 1

[0133]

[0134]

[0135] The test results are shown in Table 1. Referring to Example 1 and Comparative Examples 1-3, it can be seen that the performance of the undoped and uncoated samples is inferior to that of the doped and coated samples at -10℃. This indicates that Ti doping can reduce the migration barrier of sodium ions, improve the high-rate charge-discharge capability of the material, and simultaneously increase the band gap and reduce the electronic conductivity. Referring to Example 1 and Comparative Examples 4-6, it can be seen that Al2O3 coating can inhibit the adsorption of water molecules and improve surface stability. However, higher levels of Ti and Al2O3 doping actually worsen the cycling performance. Both Ti and Al2O3 are inert substances, and adding too much can hinder ion migration; therefore, appropriate values ​​are necessary. Referring to Example 1 and Comparative Examples 7-8, it can be seen that the samples with both Al2O3 coating and Ti doping have better cycling performance compared to materials with single modification.

[0136] In addition, combined Figures 1 to 3 In some embodiments, a cell module 300 is also provided, including the electrode 100, unipolar electrode 310, and separator 320 as described in any of the above embodiments. Multiple electrode 100s are stacked, and this stacked arrangement achieves efficient utilization of the internal space of the battery.

[0137] Two unipolar electrodes 310 are provided, and the two unipolar electrodes 310 are respectively provided at both ends of the plurality of electrodes 100. Each of the two unipolar electrodes 310 includes a current collector and an active layer located on one side of the current collector. The current collector can be the current collector 110 mentioned above, and the active layer can be the positive active layer 120 and the negative active layer 130 mentioned above.

[0138] It is understood that the two unipolar electrodes 310 can be a positive electrode 310 and a negative electrode 310, respectively. One of them has a positive electrode active layer 120 coated on one side, and the other has a negative electrode active layer 130 coated on one side.

[0139] The active layer is located on the side of the current collector facing the electrode 100, that is, the end faces of the two unipolar electrodes 310 coated with the positive electrode active layer 120 or the negative electrode active layer 130 are positioned facing the electrode 100.

[0140] The diaphragm 320 is disposed between two adjacent electrodes 100 and between the adjacent electrode 100 and the unipolar electrode 310.

[0141] Specifically, for the separator 320 disposed between two adjacent electrodes 100, one side surface of the separator 320 is in contact with the positive active layer 120 of one of the electrodes 100, and the other side surface of the separator 320 is in contact with the negative active layer 130 of the other electrode 100; for the separator 320 disposed between adjacent electrodes 100 and unipolar electrodes 310, one side surface of the separator 320 is in contact with the positive active layer 120 (or negative active layer 130) of the electrode 100, and the other side surface of the separator 320 is in contact with one side of the unipolar electrode 310 coated with the negative active layer 130 (or positive active layer 120).

[0142] The separator 320 serves to isolate the positive and negative electrodes, prevent short circuits, and allow lithium ions to pass through during charging and discharging. The direct contact between the separator 320 and the positive electrode active layer 120 and the negative electrode active layer 130 ensures efficient lithium ion transport during charging and discharging. This allows the two electrodes 100 to be directly connected through the separator 320, forming a complete cell 200 structure.

[0143] For example, the diaphragm 320 may be formed from one or a combination of polyethylene, polypropylene, or both.

[0144] It is understandable that the separator 320 and two adjacent electrode plates 100 can constitute a battery cell 200. Correspondingly, the separator 320, adjacent electrode plates 100, and unipolar electrode plates 310 can also constitute a battery cell 200. The stacked arrangement of the separator 320, multiple electrode plates 100, and two unipolar electrode plates 310 can collectively constitute a battery cell module 300. The battery cell module 300 realizes the series connection between multiple electrode plates 100, and the overall capacity of the battery cell module 300 is increased by setting multiple electrode plates 100.

[0145] As can be seen, in the battery cell module, the design of the battery cell module 300 allows the unipolar electrode 310 with the positive electrode active layer 120 or the positive electrode active layer 120 of one of the battery cells 200 to directly transmit current to its current collector 110. Then, the current is directly transmitted through the current collector 110 to the negative electrode active layer 130 of the adjacent battery cell 200 or the adjacent unipolar electrode 310 with the negative electrode active layer 130. In this way, the loss in the current transmission process is reduced and the overall efficiency of the battery cell module is improved.

[0146] In addition, it increases the density of the battery pack 400 within a limited space and reduces the number of connecting wires, thereby improving the integration of the battery pack 400.

[0147] In addition, combined Figure 1 and Figure 3The battery cell module 300 may also include an electrolyte 330. Exemplarily, the electrolyte 330 may be composed of lithium salts (such as lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, etc.), organic solvents, and additives. Additionally, the battery cell module 300 may also include a seal 340, which is disposed on the sidewall of the battery cell 200 to seal the electrolyte 330.

[0148] refer to Figure 8 This is a schematic diagram of the cycle of the battery cell module 300.

[0149] The battery cell module 300 underwent 1C / 1C charge / discharge cycle testing at -10℃: When the positive electrode material of the cell was a lithium-sodium mixture, the capacity retention rate was 85.9% after 50 cycles; when the positive electrode material was lithium-sodium-titanium / aluminum oxide, the capacity retention rate was 89.2% after 50 cycles; when the positive electrode material was a lithium-sodium mixture and the cell was wrapped with an external thermal insulation composite plate 420, the capacity retention rate was 89.9% after 50 cycles; and when the positive electrode material was lithium-sodium-titanium / aluminum oxide and the cell was wrapped with an external thermal insulation composite plate 420, the capacity retention rate was 93.4% after 50 cycles. It is evident that doping the positive electrode with titanium and coating with aluminum oxide, followed by wrapping with the thermal insulation composite plate 420 of the battery pack 400, effectively improves the cycle life of the battery cell.

[0150] Table 2

[0151] Time (min) Temperature (°C) 0 2.3 10 9.5 20 15 30 18.4 40 20.9 50 22.9 60 24.2

[0152] Table 2 shows the surface temperature during the cell discharge process. First, the cell module 300 was wrapped with a thermal insulation composite board 420 and then placed at -10℃ for charging to a full charge. After resting for 10 hours, the cell module 300 was subjected to a 3C discharge for 10 seconds, followed by a 1C constant current discharge. The surface temperature was recorded, showing that the surface temperature rose to 9.5℃ in about 10 minutes and reached 15℃ after 20 minutes. Simultaneously, the energy utilization efficiency reached 89.3%.

[0153] Additionally, in some embodiments, a battery pack 400 is also provided, see reference. Figures 4-6 The battery pack 400 includes a housing, a battery cell module 300, a phase change composite plate 410, and an insulation composite plate 420. The housing protects the internal components of the battery pack 400 from external impacts and moisture intrusion, thus protecting them from mechanical damage and environmental influences. For example, the housing can be made of materials such as aluminum, steel, or aluminum-plastic film.

[0154] The battery cell modules 300 are arranged in multiple layers, which makes full use of the internal space of the battery pack 400 and also realizes the series connection between multiple battery cell modules 300 to ensure energy density.

[0155] The phase change composite plate 410 is sandwiched between two adjacent cell modules 300. The phase change composite plate 410 can absorb heat when the temperature of the cell module 300 rises and release heat when the temperature of the cell module 300 drops, which helps to keep the cell module 300 within a suitable operating temperature range and improve the performance and safety of the battery pack 400.

[0156] The thermal insulation composite plate 420 has good thermal insulation performance, which can reduce heat exchange between the inside of the battery pack 400 and the external environment. There are two thermal insulation composite plates 420, one of which is located on top of the multiple cell modules 300, and the other is located at the bottom of the multiple cell modules 300. By setting two thermal insulation composite plates 420, the end cell modules 300 are protected.

[0157] The synergistic effect of the phase change composite plate 410 and the thermal insulation composite plate 420 helps to keep the cell module 300 within a suitable operating temperature range, prevents safety issues such as overheating and short circuits in the cell module 300, and improves the performance and safety of the battery pack 400.

[0158] In addition, compared with the prior art, where the heating film and cold plate are usually applied to the side of the cell, in this embodiment, the phase change composite plate 410 is sandwiched between adjacent cell modules 300 and the heat insulation composite plate 420 is attached to the end of the cell module 300, which increases the contact area with the cell module 300, ensures the temperature conduction efficiency, and improves the protection effect of the cell module 300.

[0159] In summary, using a lithium-sodium composite bipolar power battery can increase the space utilization of the battery cell, improve the low-temperature discharge energy of the battery cell, and thus increase the battery's driving range.

[0160] In some embodiments, refer to Figure 4 and Figure 5 The phase change composite plate 410 includes a first phase change layer 411 and a first thermally conductive layer 412.

[0161] The first phase change layer 411 is the core part of the phase change composite plate 410. It can absorb heat when the temperature of the cell module 300 rises, thereby reducing the temperature of the cell module 300. Correspondingly, when the temperature of the cell module 300 drops, the phase change material will release the heat it previously absorbed, helping the cell module 300 maintain a suitable operating temperature.

[0162] There are two first thermally conductive layers 412, located on opposite sides of the first phase change layer 411. These first thermally conductive layers 412 transfer heat generated by the battery cell module 300 to the first phase change layer 411. Furthermore, they evenly distribute the heat absorbed or released by the first phase change layer 411 throughout the entire battery pack 400, achieving uniform thermal management. For example, the first thermally conductive layers 412 can be made of materials with high thermal conductivity, such as metals or graphite.

[0163] When the temperature of the cell module 300 rises, the first thermally conductive layer 412 can transfer heat to the first phase change layer 411. The first phase change layer 411 absorbs this heat by undergoing a phase change, thereby reducing the temperature of the cell module 300. In this way, the battery pack 400 can maintain a lower temperature when operating under high load, improving the performance and safety of the battery pack 400.

[0164] In addition, the first thermally conductive layer 412 can also evenly distribute the heat absorbed or released by the first phase change layer 411 to the entire battery pack 400, which helps to maintain the uniformity of the internal temperature of the battery pack 400 and reduce battery performance degradation and capacity loss caused by temperature differences.

[0165] In some embodiments, refer to Figure 4 and Figure 6 The thermal insulation composite panel 420 includes a second phase change layer 421, a second thermally conductive layer 422, and a thermal insulation layer 423.

[0166] The second phase change layer 421 is similar to the first phase change layer 411 in the phase change composite plate 410. The second phase change layer 421 can absorb heat when the temperature of the cell module 300 rises and release heat when the temperature of the cell module 300 drops, thereby realizing thermal management of the cell module 300.

[0167] The second thermally conductive layer 422 is disposed on the side of the second phase change layer 421 facing the battery module 300, and serves to transfer the heat generated by the battery module 300 to the second phase change layer 421. Furthermore, the second thermally conductive layer 422 can also transfer the heat absorbed or released by the second phase change layer 421 to the battery module 300, realizing heat exchange between the battery module 300 and the insulation composite board 420. For example, the second thermally conductive layer 422 can be made of a material with high thermal conductivity, such as metal or graphite.

[0168] The thermal insulation layer 423 is located on the side of the second phase change layer 421 facing away from the cell module 300, and serves to prevent heat loss from the inside of the battery pack 400 to the external environment. By improving the thermal insulation performance of the thermal insulation layer 423, heat exchange between the inside of the battery pack 400 and the external environment can be reduced, thereby maintaining the stability of the internal temperature of the battery pack 400. Ideally, the thermal insulation layer 423 can be made of materials with low thermal conductivity to achieve fire-resistant and heat-insulating functions, such as aerogel or foam plastics.

[0169] Through the synergistic effect of the second phase change layer 421 and the second thermal conductive layer 422, the battery pack 400 can dissipate heat when the temperature of the cell module 300 rises and maintain the stability of the internal temperature when the temperature of the cell module 300 drops. In addition, the thermal insulation layer 423 can further reduce the heat exchange between the inside of the battery pack 400 and the external environment, and improve the thermal insulation effect of the battery pack 400.

[0170] In addition, in some embodiments, an electrical device is provided that can be an electric vehicle, an electric bicycle, an energy storage system, a portable electronic device (such as a laptop, tablet, or smartphone), a drone, a ship, or aerospace equipment, which relies on the power supply provided by the battery pack 400.

[0171] The electrical device may include the battery pack 400 in any of the above embodiments. By incorporating the battery pack 400 into the electrical device, the battery pack 400 reduces losses during current transmission, improves the overall efficiency and density of the battery cell module, and thus improves the power efficiency and safety of the electrical device.

[0172] It should be noted that the embodiments referred to in the specification, such as "one embodiment," "embodiment," "exemplary embodiment," and "some embodiments," may include specific features, structures, or characteristics, but not every embodiment necessarily includes that specific feature, structure, or characteristic. Furthermore, such phrases do not necessarily refer to the same embodiment. Moreover, when a specific feature, structure, or characteristic is described in connection with an embodiment, implementing such a feature, structure, or characteristic in conjunction with other embodiments, whether explicitly described or not, is within the knowledge scope of those skilled in the art.

[0173] Generally speaking, terms should be understood at least in part by their use in context. For example, at least in part by context, the term "one or more" as used in the text can be used to describe any feature, structure, or characteristic of the singular meaning, or a combination of features, structures, or characteristics of the plural meaning. Similarly, at least in part by context, terms such as "a" or "the" can also be understood to convey either singular or plural usage.

[0174] It should be readily understood that the terms “on,” “above,” and “on top of” in this disclosure should be interpreted in the broadest possible sense, such that “on” means not only “directly on something” but also “on something” with an intermediate feature or layer therebetween, and that “above” or “on top of” means not only “on top of something” but also “on top of something” without an intermediate feature or layer therebetween (i.e., directly on something).

[0175] Furthermore, for ease of explanation, spatially relative terms such as "below," "below," "under," "above," and "above" may be used to describe the relationship of one element or feature relative to other elements or features as shown in the figures. Spatially relative terms are intended to encompass different orientations of the device in use or operation other than those shown in the figures. The device may have other orientations (rotated 90 degrees or in other orientations), and the spatially relative descriptive terms used herein may be interpreted accordingly.

[0176] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. An electrode (100), characterized in that, include: The current collector (110) includes a first surface (111) and a second surface (112) opposite each other along the thickness direction; A positive electrode active layer (120) is disposed on the first surface (111), the positive electrode active layer (120) includes a positive electrode active material, the positive electrode active material includes lithium-based active material and sodium-based active material; A negative electrode active layer (130) is disposed on the second surface (112).

2. The electrode (100) according to claim 1, characterized in that, The lithium-based active material includes at least one of lithium iron phosphate, lithium nickel cobalt manganese oxide, lithium manganese oxide, lithium cobalt oxide, and lithium manganese iron phosphate.

3. The electrode (100) according to claim 1, characterized in that, The sodium-based active material includes at least one of the following: layered structure type, Prussian blue analog cathode, and polyanionic type.

4. The electrode (100) according to claim 1, characterized in that, The molar ratio of lithium to sodium in the positive electrode active material ranges from 0.1 to 50.

5. The electrode (100) according to claim 1, characterized in that, The positive electrode active material (120) also includes aluminum oxide.

6. The electrode (100) according to claim 5, characterized in that, The aluminum oxide accounts for 0.1%-5% of the positive electrode active layer (120) by mass percentage.

7. The electrode (100) according to claim 1, characterized in that, The positive electrode active material (120) also includes doping elements, including titanium.

8. The electrode (100) according to claim 7, characterized in that, The molar percentage of titanium in the positive electrode active material is 0.1%-5%.

9. The electrode (100) according to claim 1, characterized in that, The current collector (110) is a copper-aluminum composite current collector (110).

10. A method for preparing an electrode (100), used to prepare the electrode (100) according to any one of claims 1-9, characterized in that, Includes the following steps: The lithium source and sodium source are mixed and then ground. The ground powder is then dried. The powder is sintered at high temperature to obtain a positive electrode material; The cathode material was doped with aluminum oxide and then ground.

11. The method for preparing the electrode (100) according to claim 10, characterized in that, The process of mixing and grinding lithium and sodium sources includes adding titanium to the lithium and sodium sources.

12. A battery cell module (300), characterized in that, include: The electrode (100) according to any one of claims 1-9, wherein a plurality of said electrode (100) are stacked and arranged; Two unipolar electrodes (310) are respectively disposed at both ends of a plurality of electrodes (100). Each unipolar electrode (310) includes a current collector and an active layer located on one side of the current collector. The active layer is located on the side of the current collector facing the electrode (100). A diaphragm (210) is disposed between two adjacent electrodes (100) and between adjacent electrodes (100) and the unipolar electrode (310).

13. A battery pack (400), characterized in that, include: case; The battery cell module (300) according to claim 12, wherein the battery cell module (300) comprises a plurality of cells arranged in a stacked manner; A phase change composite plate (410) is sandwiched between two adjacent battery cell modules (300); Thermal insulation composite board (420), there are two thermal insulation composite boards (420), one thermal insulation composite board (420) is disposed on the top of the plurality of battery cell modules (300), and the other thermal insulation composite board (420) is disposed on the bottom of the plurality of battery cell modules (300).

14. The battery pack (400) according to claim 13, characterized in that, The phase change composite plate (410) includes: First phase change layer (411); The first thermal conductive layer (412) consists of two layers, which are located on opposite sides of the first phase change layer (411).

15. The battery pack (400) according to claim 13, characterized in that, The thermal insulation composite board (420) includes: Second phase change layer (421); The second thermally conductive layer (422) is disposed on the side of the second phase change layer (421) facing the cell module (300); A thermal insulation layer (423) is disposed on the side of the second phase change layer (421) facing away from the battery cell module (300).

16. An electrical appliance, characterized in that, Includes the battery pack (400) according to any one of claims 13-15.

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