Battery pack and electric equipment

Abstract

The battery pack comprises a first power supply unit which comprises a first anode pole piece, the first anode pole piece comprises a silicon-based material, and based on the mass of an active substance in the first anode pole piece, the content of the silicon-based material is greater than or equal to 50%; the second power supply unit comprises a second anode pole piece, and the second anode pole piece comprises graphite; the battery management system is configured to obtain the voltage and the charge state of the first power supply unit; and in response to the voltage less than or equal to the first voltage threshold and the charge state less than or equal to the first charge state threshold, controlling the first power supply unit to be in a dormant state, and controlling the second power supply unit to supply energy.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a battery pack and an electrical device. Background Technology

[0002] As the country vigorously promotes new energy equipment, its market share is constantly increasing, and people's requirements for new energy equipment are also getting higher and higher. For example, the energy storage batteries in new energy equipment need to have higher energy density and longer service life.

[0003] Currently, the most commonly used energy storage batteries in new energy equipment are lithium-ion batteries. Lithium-ion batteries typically use silicon-based anodes or graphite anodes, but these types of lithium-ion batteries cannot simultaneously achieve high energy density and long service life. Summary of the Invention

[0004] This application provides a battery pack and an electrical device that can improve the energy density of the battery pack and extend its service life.

[0005] In a first aspect, embodiments of this application provide a battery pack, which includes a first power supply unit, a second power supply unit, and a battery management system. The first power supply unit includes a first anode electrode, which comprises a silicon-based material, and the content of the silicon-based material is greater than or equal to 50% based on the mass of the active material in the first anode electrode. The second power supply unit includes a second anode electrode, which comprises graphite. The battery management system is configured to: acquire the voltage and state of charge of the first power supply unit; and, in response to a voltage less than or equal to a first voltage threshold and a state of charge less than or equal to the first state of charge threshold, control the first power supply unit to enter a dormant state and control the second power supply unit to supply power.

[0006] The battery pack incorporates a first anode electrode made of silicon-based material, with a relatively high silicon content, resulting in a higher capacity and contributing to increased overall energy density. The voltage of the first power supply unit is below a first voltage threshold, and its state of charge (SOC) is less than or equal to the first SOC threshold. This indicates that the power supply unit's charge has been depleted to a minimum. When the SOC's SOC is depleted to a minimum, it enters a dormant state, ceasing power supply to reduce the likelihood of silicon dormancy and extend its lifespan, thus extending the battery pack's lifespan. Furthermore, while the first power supply unit is in dormant mode, the second power supply unit continues to supply power to maintain the battery pack's continuous functionality.

[0007] In one or more embodiments, the battery management system is further configured to: control the first power supply unit to supply power and control the second power supply unit to be in a dormant state in response to a voltage greater than a first voltage threshold and / or a state of charge greater than a first state of charge threshold.

[0008] If at least one of the following conditions is met: the voltage of the first power supply unit is greater than the first voltage threshold, or the state of charge (SBC) of the first power supply unit is greater than the first SBC threshold, it means that the first power supply unit still has a significant amount of charge and can still be used for power supply. In this case, the first power supply unit is prioritized for power supply to maximize system performance and power output. Furthermore, the second power supply unit is controlled to be in a dormant state to maintain sufficient charge, thus enabling it to be used as a backup power source when the first power supply unit stops supplying power, thereby maintaining a stable power supply to the battery pack. In one or more embodiments, the battery management system is further configured to: control the first power supply unit to supply power and control the second power supply unit to be in a sleep state in response to the target output power of the battery pack being a first power; control the second power supply unit to supply power and control the first power supply unit to be in a sleep state in response to the target output power of the battery pack being a second power, wherein the first power is greater than the second power.

[0009] The target output power of the battery pack is the first power, meaning the battery pack needs to output higher power. In this case, using the first power supply unit, which can provide more power, not only meets the demand but also maximizes system performance and power output. Simultaneously, the second power supply unit is kept in a dormant state to maintain sufficient charge, allowing it to serve as a backup power source when the first power supply unit stops supplying power, thus ensuring a stable power supply to the battery pack. Alternatively, if the target output power of the battery pack is the second power, meaning the battery pack only needs to output lower power, using the second power supply unit, which can provide less power, can meet the demand while reducing energy consumption. Simultaneously, keeping the first power supply unit in a dormant state prevents the second power supply unit from experiencing silicon dormancy during shallow charging and discharging, thereby extending the lifespan of the second power supply unit.

[0010] In one or more embodiments, the battery management system is further configured to: control the first power supply unit to supply power and control the second power supply unit to be in a sleep state in response to a first frequency modulation command; control the second power supply unit to supply power and control the first power supply unit to be in a sleep state in response to a second frequency modulation command, wherein the rate of change of the grid frequency corresponding to the first frequency modulation command is greater than the rate of change of the grid frequency corresponding to the second frequency modulation command.

[0011] The first frequency regulation command corresponds to a relatively large change in grid frequency, indicating a high-frequency regulation command. In this case, using the first power supply unit facilitates rapid response. Simultaneously, the second power supply unit is kept in a dormant state to maintain sufficient charge, allowing it to serve as a backup power source when the first power supply unit stops supplying power, thus ensuring stable power supply to the battery pack. The second frequency regulation command corresponds to a relatively small change in grid frequency, meaning only low-frequency, slow, and continuous power demands need to be met, such as the power requirements of the base load. In this case, using the second power supply unit, which provides less power, can meet the demand while reducing energy consumption. Simultaneously, keeping the first power supply unit in a dormant state prevents the second power supply unit from experiencing silicon dormancy during shallow charging and discharging, thereby extending its lifespan.

[0012] In one or more embodiments, the first power supply unit further includes a first cathode electrode, which comprises a lithium transition metal oxide containing nickel. Based on the total molar mass of metal atoms other than Li atoms in the active material of the first cathode electrode, the molar proportion of nickel in the lithium transition metal oxide is greater than or equal to 80%.

[0013] The molar percentage of nickel in lithium transition metal oxide is greater than or equal to 80%, which means that the nickel content in lithium transition metal oxide is relatively high, so that the first power supply unit has a high energy density.

[0014] In one or more embodiments, the second power supply unit further includes a second cathode electrode, which includes at least one of lithium iron phosphate, lithium manganese oxide, or lithium cobalt oxide.

[0015] In one or more embodiments, the ratio of the capacity of the first power supply unit to the total capacity is 50%-80%, wherein the total capacity is the sum of the capacities of the first power supply unit and the second power supply unit.

[0016] The first power supply unit has a larger capacity and can be used as the main power supply unit, while the second power supply unit can be used as an auxiliary power supply unit to ensure that the battery pack has a high energy density.

[0017] In one or more embodiments, the first power supply unit uses a prismatic cell or a pouch cell.

[0018] The first power supply unit uses prismatic cells, which allows for a larger capacity design, thus meeting the requirement of using the first power supply unit as the primary power supply unit. The first power supply unit also uses pouch cells, which helps improve the energy density of the battery pack and reduces the risk of thermal runaway.

[0019] In one or more embodiments, the second power supply unit employs cylindrical or hard-shell cells.

[0020] The second power supply unit uses cylindrical cells, which helps improve the stability of the battery pack. The second power supply unit also uses hard-shell cells. On one hand, the metal casing of the hard-shell cells effectively resists external compression, puncture, and vibration, improving the overall safety of the battery pack; on the other hand, the hard-shell cells have a mature manufacturing process and a longer cycle life, thus contributing to a longer cycle life of the battery pack.

[0021] In one or more embodiments, the first voltage threshold is 2.8V.

[0022] Setting the first voltage threshold to 2.8V can effectively and promptly reduce the likelihood of silicon dormancy.

[0023] In one or more embodiments, the first state of charge threshold is 5%.

[0024] Setting the first state of charge threshold to 5% can effectively and promptly reduce the likelihood of silicon dormancy.

[0025] Secondly, embodiments of this application provide an electrical device, including a load and a battery pack as described in the first aspect. Attached Figure Description

[0026] One or more embodiments are illustrated by way of example with reference to the accompanying drawings, which are not intended to limit the embodiments, and elements having the same reference numerals in the drawings are designated as similar elements.

[0027] Figure 1 This is a schematic diagram of the battery pack provided in the embodiments of this application. Figure 1 ; Figure 2 This is a schematic diagram of the battery pack provided in the embodiments of this application. Figure 2 ; Figure 3 This is a schematic diagram of the method steps executed by the battery management system provided in the embodiments of this application. Figure 1 ; Figure 4 This is a schematic diagram of the method steps executed by the battery management system provided in the embodiments of this application. Figure 2 ; Figure 5 This is a schematic diagram of the method steps executed by the battery management system provided in the embodiments of this application. Figure 3 ; Figure 6 This is a schematic diagram of the method steps executed by the battery management system provided in the embodiments of this application. Figure 4 ; Figure 7 This is a schematic diagram of the method steps executed by the battery management system provided in the embodiments of this application. Figure 5 . Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and thoroughly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0029] It should be noted that when an element is described as "connected" to another element, it can be directly connected to the other element, or there can be one or more intermediate elements between them.

[0030] Furthermore, the technical features involved in the various embodiments of this application described below can be combined with each other as long as they do not conflict with each other.

[0031] Please refer to Figure 1 , Figure 1 One battery structure provided in an embodiment of this application. For example... Figure 1 As shown, the battery 10 includes a first power supply unit 11, a second power supply unit 12, and a battery management system 13.

[0032] Optionally or additionally, the ratio of the capacity of the first power supply unit 11 to the total capacity is 50%-80%, where the total capacity is the sum of the capacities of the first power supply unit 11 and the second power supply unit 12. Correspondingly, the ratio of the capacity of the second power supply unit 12 to the total capacity is 20%-50%. That is, the capacity of the first power supply unit 11 is at least equal to the capacity of the second power supply unit 12, and at most four times the capacity of the second power supply unit 12. In this way, the first power supply unit 11 serves as the main power supply unit, and the second power supply unit 12 serves as the auxiliary power supply unit, to ensure that the battery pack 10 has a high energy density.

[0033] Optionally or additionally, when the battery pack 10 is used in an electric vehicle, the ratio of the capacity of the first power supply unit 11 to the total capacity is 70%, and the ratio of the capacity of the second power supply unit 12 to the total capacity is 30%.

[0034] Optionally or additionally, the first power supply unit 11 is responsible for daily operation and long battery life, providing the majority of the energy; the second power supply unit 12 is responsible for power supply under specific circumstances, such as when the first power supply unit 11 is in hibernation or disconnected.

[0035] The first power supply unit 11 includes a first anode plate 111, where the anode is the negative electrode. The first anode plate 111 is made by coating a metal foil (usually copper foil) with a mixture of active materials, conductive agents, binders, etc.

[0036] The first anode electrode 111 includes a silicon-based material, which may include, but is not limited to, elemental silicon and silicon oxide (SiO2). x The silicon-metal composite material comprises at least one of the following: 0 < x < 2; ...

[0037] Based on the mass of the active material in the first anode electrode 111, the content of silicon-based material is greater than or equal to 50%. Here, active material refers to the material in the negative electrode of the battery that participates in the lithium-ion insertion and extraction reaction. Besides silicon-based materials, it may also include other active materials such as graphite, hard carbon, and soft carbon. The calculation benchmark is clearly defined as the mass of the active material, not the mass of the entire electrode (including conductive carbon black, binder, current collector, etc.). This means that when calculating the proportion, the denominator is the sum of the masses of all active materials in the first anode electrode 111, and the numerator is the mass of silicon-based material or silicon composite material. A silicon-based material content of greater than or equal to 50% indicates a high proportion of silicon-based material in the first anode electrode, thus giving the first anode electrode 111 a higher theoretical capacity and contributing to an increase in the overall energy density of the battery pack 10.

[0038] Optionally or additionally, the first power supply unit 11 further includes a first cathode electrode 112, which comprises a lithium transition metal oxide containing nickel. Based on the total molar mass of metal atoms other than Li atoms in the active material of the first cathode electrode 112, the molar proportion of nickel in the lithium transition metal oxide is greater than or equal to 80%.

[0039] Specifically, lithium transition metal oxides refer to inorganic compounds composed of lithium (Li), oxygen (O), and one or more transition metals (M), with the chemical formula LiNi. x Co y M 1-x-y O2 (x≥0.85, 0<y≤0.1), where M can be selected from Mn or Al, or it can be coated or doped.

[0040] Based on the total molar mass of the active material in the first cathode electrode 112, excluding Li atoms, the molar percentage of nickel in the lithium transition metal oxide is greater than or equal to 80%. It is clarified that the calculation basis is the mass of the active material in the first cathode electrode 112, not the mass of the entire electrode (including conductive carbon black, binder, current collector, etc.). Therefore, the molar percentage of nickel does not refer to the weight percentage of nickel in the entire cathode electrode, but rather the percentage of nickel atoms (Ni) out of the total number of transition metal atoms (such as Ni, Mn, Co, Al, etc.) in the active material. For example, in NCM811 (i.e., LiNi... 0.8 Co 0.1 Mn 0.1 In O2, the molar ratio of nickel, manganese, and cobalt is 8:1:1, so the molar percentage of nickel is 8 / (8+1+1)=80%; For example, LiNi 0.90 Co 0.05 Mn 0.05 In O2, the molar ratio of nickel, manganese, and cobalt is 9:0.5:0.5, so the molar percentage of nickel is 9 / (9+0.5+0.5)=90%. The molar percentage of nickel in lithium transition metal oxide is greater than or equal to 80%, which means that the nickel content in lithium transition metal oxide is relatively high, so that the first power supply unit 11 has a high energy density.

[0041] Optionally or additionally, the first power supply unit 11 uses prismatic cells or pouch cells.

[0042] A prismatic battery cell refers to a single battery cell packaged in a square, rigid shell. Prismatic battery cells typically use aluminum alloy or stainless steel to create a rigid casing, providing good mechanical strength and protection. The electrodes (positive and negative) and separator inside the prismatic battery cell can be either jelly-rolled or stacked. Using a prismatic battery cell in the first power supply unit 11 allows for the design of a larger capacity, thus meeting the requirement that the first power supply unit 11 be the primary power supply unit.

[0043] A pouch cell is a single cell encapsulated using aluminum-plastic film as its outer shell. Because it uses a lightweight aluminum-plastic film instead of a metal shell, a pouch cell is lighter than a steel- or aluminum-cased battery of the same capacity, which helps to improve energy density (especially gravimetric energy density). Furthermore, in the event of thermal runaway or increased internal pressure, a pouch cell typically bulges or cracks to release the pressure, unlike a hard-shell battery which may explode. Therefore, the overall risk of thermal runaway is relatively low. The use of pouch cells in the first power supply unit 11 is beneficial for improving the energy density of the battery pack 10 and reducing the risk of thermal runaway.

[0044] The second power supply unit 12 includes a second anode plate 121, which is made by coating a metal foil (usually copper foil) with a mixture of active material, conductive agent, binder and the like.

[0045] The second anode electrode 121 includes graphite, which includes at least one of artificial graphite and / or natural graphite. Using graphite, which has a stable structure and long cycle life, as the negative electrode material enables it to serve as a backup power source, supplementing the required power when the first power supply unit 11 is in sleep mode, ensuring a stable power supply to the battery pack 10.

[0046] Optionally or additionally, the second power supply unit 12 further includes a second cathode electrode 121. The second cathode electrode includes at least one of lithium iron phosphate, lithium manganese oxide, or lithium cobalt oxide. Among them, lithium iron phosphate (LiFePO4) has high safety, long cycle life, and low cost; lithium manganese oxide (LiMn2O4) has high safety and low cost; and lithium cobalt oxide (LiCoO2) has high energy density.

[0047] Optionally or additionally, since the second power supply unit 12 is an auxiliary unit and usually only supplements the required power when the first power supply unit 11 stops supplying power, materials with higher safety and lower cost, such as lithium iron phosphate or lithium manganese oxide, are preferred to ensure reliable and stable power supply to the battery pack 10 and reduce the cost of the battery pack 10.

[0048] Optionally or additionally, the second power supply unit 12 may use cylindrical or hard-shell cells.

[0049] A cylindrical battery cell is a lithium-ion battery cell encapsulated in a cylindrical metal casing made of nickel-plated steel or aluminum alloy. Cylindrical cells are sealed in a cylindrical metal casing (usually steel or aluminum), and the internal electrodes employ a wound structure, offering advantages such as structural stability, mature technology, and a high degree of automation. The use of cylindrical cells in the second power supply unit 12 helps improve the stability of the battery pack 10.

[0050] Hard-shell cells refer to lithium-ion cells that use metal materials (such as aluminum alloy, stainless steel, or nickel-plated steel) as their outer casing, possessing high mechanical strength and sealing performance. The second power supply unit 12 uses hard-shell cells. On one hand, the metal casing of hard-shell cells can effectively resist external compression, puncture, and vibration, improving the overall safety of the battery pack 10; on the other hand, the manufacturing process of hard-shell cells is mature, resulting in a longer cycle life, which helps to improve the cycle life of the battery pack 10.

[0051] Figure 1Taking battery 10 as an example, which includes a first power supply unit 11 and a second power supply unit 12. Optionally or additionally, battery 10 includes N first power supply units 11 and M second power supply units 12, where N and M are both positive integers greater than 0, and N and M can be the same or different. For example, Figure 2 As shown, N=M=2, meaning that battery 10 includes two first power supply units 11 and two second power supply units 12.

[0052] Please refer to Figure 3 , Figure 3 A flowchart illustrating the method performed by the Battery Management System (BMS) 13 provided in this embodiment of the application. Figure 3 As shown, the battery management system 13 is configured to perform steps S310 to S320.

[0053] Step S310: Obtain the voltage and state of charge of the first power supply unit.

[0054] Optionally or additionally, the voltage of the first power supply unit 11 can be measured using a voltage sampling circuit (such as a voltage divider resistor network), or the voltage of the first power supply unit 11 can be acquired with high precision using a BMS acquisition module (such as an AFE, analog front-end chip).

[0055] The State of Charge (SOC) refers to the ratio of the battery's current remaining charge to its rated capacity when fully charged, usually expressed as a percentage (%). For example, SOC = 100% indicates that the first power supply unit 11 is fully charged. Optionally or additionally, the state of charge of the first power supply unit 11 can be determined by methods such as the open-circuit voltage method (OCV-SOC) or the ampere-hour integration method (Coulomb Counting). Taking the ampere-hour integration method as an example, by measuring the charging and discharging current during the charging and discharging process of the first power supply unit 11 and integrating the charging and discharging current over time, the total amount of charge flowing into or out of the first power supply unit 11 is calculated. Then, combined with the rated capacity of the first power supply unit 11, the current state of charge of the first power supply unit 11 is deduced.

[0056] Step S320: In response to the voltage being less than or equal to a first voltage threshold and the state of charge being less than or equal to a first state of charge threshold, control the first power supply unit to be in a sleep state and control the second power supply unit to supply power.

[0057] The voltage of the first power supply unit 11 is less than the first voltage threshold, and the state of charge of the first power supply unit 11 is less than or equal to the first state of charge threshold. This means that the amount of electricity in the first power supply unit 11 has been consumed to a small value. At this time, if the first power supply unit 11 continues to supply power, metastable Li is easily formed in the first anode plate. 15The Si4 phase causes particle breakage and loss of active material during subsequent charge-discharge cycles (i.e., "silicon dormancy"), leading to accelerated capacity degradation of the first power supply unit 11 and a shortened lifespan. Therefore, when the charge in the first power supply unit 11 is depleted to a low level, it is controlled to enter a dormancy state, i.e., the first power supply unit 11 stops supplying power, reducing the probability of silicon dormancy and thus extending its lifespan, and consequently, the lifespan of the battery pack 10. Furthermore, while the first power supply unit 11 is in a dormancy state, the second power supply unit 12 is controlled to supply power to maintain the continuous function of the battery pack 10.

[0058] The first voltage threshold is a preset voltage value, and the first state of charge threshold is a preset state of charge value. Both can be set based on the actual application scenario, and this application embodiment does not impose specific restrictions on them.

[0059] Optionally or additionally, the first voltage threshold is 2.8V, and / or the first state of charge threshold is 5%. When the voltage of the first power supply unit 11 is less than or equal to 2.8V, and / or the state of charge of the first power supply unit 11 is less than or equal to 5%, the risk of silicon dormancy in the first power supply unit 11 increases sharply as the voltage decreases. Based on this, setting the first voltage threshold to 2.8V, and / or setting the first state of charge threshold to 5%, can reduce the probability of silicon dormancy in a timely and effective manner.

[0060] Optionally or additionally, such as Figure 4 As shown, the battery management system 13 is also used to perform the following step S410.

[0061] Step S410: In response to the voltage being greater than a first voltage threshold and / or the state of charge being greater than a first state of charge threshold, control the first power supply unit to supply power and control the second power supply unit to be in a sleep state.

[0062] If at least one of the following conditions is met: the voltage of the first power supply unit 11 is greater than the first voltage threshold, or the state of charge of the first power supply unit 11 is greater than the first state of charge threshold, it means that the first power supply unit 11 still has a sufficient amount of charge and can still be used for power supply. In this case, the first power supply unit 11 is preferentially selected to supply power to maximize system performance and power output. In addition, the second power supply unit 12 is controlled to be in a sleep state so that the second power supply unit 12 maintains sufficient charge and can be used as a backup power source when the first power supply unit 11 stops supplying power, thereby maintaining a stable power supply to the battery pack 10.

[0063] Optionally or additionally, such as Figure 5As shown, the battery management system 13 is also used to perform the following steps S510 to S520.

[0064] Step S510: In response to the target output power of the battery pack being the first power, control the first power supply unit to supply power and control the second power supply unit to be in a sleep state.

[0065] Step S520: In response to the target output power of the battery pack being the second power, control the second power supply unit to supply power and control the first power supply unit to be in a sleep state, wherein the first power is greater than the second power.

[0066] Specifically, the target output power of the battery pack 10 is the first power, which means that the battery pack 10 needs to output a higher power. At this time, the first power supply unit 11, which can provide more electrical energy, is used to supply power, which can not only meet the demand, but also maximize system performance and power output. At the same time, the second power supply unit 12 is controlled to be in a sleep state so that the second power supply unit 12 can maintain sufficient power and thus be used as a backup power source when the first power supply unit 11 stops supplying power, so as to maintain a stable power supply to the battery pack 10.

[0067] The target output power of the battery pack 10 is the second power, which means that the battery pack 10 only needs to output a lower power. At this time, the second power supply unit 12, which can provide less power, is used to supply power, which can reduce energy consumption while meeting the demand. At the same time, the first power supply unit 12 is controlled to be in a dormant state to avoid the silicon dormancy phenomenon of the second power supply unit 12 during shallow charging and discharging, thereby extending the service life of the second power supply unit 12.

[0068] Optionally or additionally, when the battery pack 10 is applied to an electric vehicle, the target output power of the battery pack 10 is a first power that corresponds to the application scenario when the electric vehicle is accelerating or climbing; the target output power of the battery pack 10 is a second power that corresponds to the application scenario when the electric vehicle is cruising or driving at a slow speed.

[0069] Optionally or additionally, such as Figure 6 As shown, the battery management system 13 is also used to perform the following steps S610 to S620.

[0070] Step S610: In response to the first frequency modulation command, control the first power supply unit to supply power and control the second power supply unit to be in a sleep state.

[0071] Step S620: In response to the second frequency modulation command, control the second power supply unit to supply power and control the first power supply unit to be in a sleep state, wherein the rate of change of the grid frequency corresponding to the first frequency modulation command is greater than the rate of change of the grid frequency corresponding to the second frequency modulation command.

[0072] Specifically, the grid frequency corresponding to the first frequency modulation command changes rapidly, meaning that the first frequency modulation command is a high-frequency frequency modulation command. In this case, the first power supply unit 11 is used to provide power, which is beneficial for achieving a rapid response. At the same time, the second power supply unit 12 is controlled to be in a sleep state so that the second power supply unit 12 maintains sufficient power and can be used as a backup power source when the first power supply unit 11 stops providing power, thereby maintaining a stable power supply to the battery pack 10.

[0073] The second frequency regulation command corresponds to a smaller grid frequency change rate, meaning that only low-frequency, slow, and continuous power demands need to be met, such as the power demand of the base load. In this case, using a second power supply unit 12, which can provide less power, can reduce energy consumption while meeting the demand. At the same time, the first power supply unit 12 is controlled to be in a dormant state to avoid silicon dormancy in the second power supply unit 12 due to shallow charging and discharging, thereby extending the service life of the second power supply unit 12.

[0074] Optionally or additionally, when the battery pack 10 is applied to a grid energy storage application scenario, step S610 is used to respond to a high-frequency frequency regulation command, and step S620 is used to meet the power demand of the base load.

[0075] Please refer to Figure 7 , Figure 7 Another flowchart illustrates the method performed by the battery management system 13 provided in this embodiment of the application. Figure 7 As shown, firstly, the voltage and state of charge of the first power supply unit 11 are acquired in real time, and the relationship between the voltage of the first power supply unit 11 and the first voltage threshold is determined in real time, as well as the relationship between the state of charge of the first power supply unit 11 and the first state of charge threshold is determined.

[0076] If it is determined that the voltage of the first power supply unit 11 is less than or equal to a first voltage threshold, and the state of charge of the first power supply unit 11 is less than or equal to a first state of charge threshold, then it is determined that the power of the first power supply unit 11 has been consumed to a small value. At this time, the first power supply unit 11 is controlled to enter a sleep state, that is, the first power supply unit 11 stops supplying power, in order to reduce the probability of the first power supply unit 11 experiencing silicon sleep phenomena, thereby extending the service life of the first power supply unit 11, that is, extending the service life of the battery pack 10. Furthermore, while the first power supply unit 11 is in a sleep state, the second power supply unit 12 is controlled to supply power to maintain the continuous function of the battery pack 10.

[0077] If the voltage is determined to be greater than the first voltage threshold, and / or the state of charge is greater than the first state of charge threshold, then the first power supply unit 11 still has a sufficient amount of charge and can still be used for power supply. In this case, the first power supply unit 11 is given priority for power supply to maximize system performance and power output. Furthermore, while the first power supply unit 11 is supplying power, the second power supply unit 12 is controlled to be in a sleep state to ensure that the second power supply unit 12 maintains sufficient charge, thus enabling it to be used as a backup power source when the first power supply unit 11 stops supplying power, thereby maintaining a stable power supply to the battery pack 10.

[0078] This application also provides an electrical device. The electrical device includes a load and a battery pack as described in any embodiment of this application, the battery pack being used to supply power to the load.

[0079] Loads include electrical components on electrical equipment such as motors, lights, horns, and instruments. Electrical equipment refers to devices that require battery power. Examples of electrical equipment include: unmanned aerial vehicles, energy storage products, power tools, and electric vehicles (electric two-wheelers, electric tricycles), etc.

[0080] The above description is merely an embodiment of this application and does not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

[0081] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Within the framework of this application, the technical features of the above embodiments or different embodiments can also be combined, and the steps can be implemented in any order. Those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A battery pack, characterized in that, include: The first power supply unit includes a first anode electrode, which comprises a silicon-based material, and the content of the silicon-based material is greater than or equal to 50% based on the mass of the active material in the first anode electrode. The second power supply unit includes a second anode plate, which includes graphite. The battery management system is configured as follows: Obtain the voltage and state of charge of the first power supply unit; In response to the voltage being less than or equal to a first voltage threshold and the state of charge being less than or equal to a first state of charge threshold, the first power supply unit is controlled to enter a sleep state, and the second power supply unit is controlled to supply power.

2. The battery pack according to claim 1, characterized in that, The battery management system is further configured to: in response to the voltage being greater than the first voltage threshold, and / or the state of charge being greater than the first state of charge threshold, control the first power supply unit to supply power, and control the second power supply unit to be in a sleep state.

3. The battery pack according to claim 1, characterized in that, The battery management system is also configured to: In response to the target output power of the battery pack being a first power, the first power supply unit is controlled to supply power, and the second power supply unit is controlled to be in a sleep state. In response to the target output power of the battery pack being a second power, the second power supply unit is controlled to supply power, and the first power supply unit is controlled to be in a sleep state, wherein the first power is greater than the second power.

4. The battery pack according to claim 1, characterized in that, The battery management system is also configured to: In response to the first frequency modulation command, the first power supply unit is controlled to supply power, and the second power supply unit is controlled to be in a sleep state; In response to the second frequency modulation command, the second power supply unit is controlled to supply power, and the first power supply unit is controlled to be in a sleep state, wherein the rate of change of the power grid frequency corresponding to the first frequency modulation command is greater than the rate of change of the power grid frequency corresponding to the second frequency modulation command.

5. The battery pack according to any one of claims 1-4, characterized in that, The first power supply unit further includes a first cathode electrode, which comprises a lithium transition metal oxide containing nickel. Based on the total molar mass of metal atoms other than Li atoms in the active material of the first cathode electrode, the molar proportion of nickel in the lithium transition metal oxide is greater than or equal to 80%.

6. The battery pack according to any one of claims 1-4, characterized in that, The second power supply unit further includes a second cathode electrode, which includes at least one of lithium iron phosphate, lithium manganese oxide, or lithium cobalt oxide.

7. The battery pack according to any one of claims 1-6, characterized in that, The ratio of the capacity of the first power supply unit to the total capacity is 50%-80%, wherein the total capacity is the sum of the capacities of the first power supply unit and the second power supply unit.

8. The battery pack according to any one of claims 1-7, characterized in that, The first power supply unit uses square-shell cells or pouch cells.

9. The battery pack according to any one of claims 1-7, characterized in that, The second power supply unit uses cylindrical cells or hard-shell cells.

10. The battery pack according to any one of claims 1-9, characterized in that, The first voltage threshold is 2.8V.

11. The battery pack according to any one of claims 1-9, characterized in that, The first state of charge threshold is 5%.

12. An electrical appliance, characterized in that, Includes a load and a battery pack as described in any one of claims 1-11.

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