Battery system for a means of transport and method for controlling the battery system for a means of transport

Abstract

The present invention relates to a battery system for a means of transport, wherein the battery system includes a secondary battery and a battery management device, the secondary battery includes a positive electrode containing a positive electrode active material, a negative electrode containing a negative electrode active material, a separator, and an electrolyte, the negative electrode active material includes a silicon-based active material and a carbon-based active material, the battery management device includes a diagnostic unit and a control unit, the diagnostic unit diagnoses the normal or abnormal operating status of the means of transport, and the control unit controls the battery system to charge and discharge the secondary battery in a first drive mode when the diagnostic unit diagnoses the normal operating status, and to charge and discharge the secondary battery in a second drive mode when the diagnostic unit diagnoses the abnormal operating status. The battery system for a means of transport according to the present invention has excellent lifespan performance and can exert high output for a long period of time when an abnormal operating status is diagnosed, thereby facilitating stable stopping or emergency landing of the means of transport.

Description

[Technical Field]

[0001] The present invention relates to a battery system for a means of transport and a method for controlling a battery system for a means of transport. [Background technology]

[0002] In recent years, the application areas of secondary batteries have rapidly expanded beyond power supply for electronic devices such as electrical, electronic, telecommunications, and computers to include power storage and supply for large-area equipment such as power storage devices, automobiles, and aerospace transport. Consequently, there is an increasing demand for secondary batteries with high capacity, high output, and high stability.

[0003] In particular, means of transportation such as automobiles, trains, and airplanes should travel along set routes, and the operating conditions of the battery system need to be adjusted according to various situations. For example, when emergency braking is required due to abnormal conditions in automobiles or trains, or when an emergency landing is considered due to abnormal operation or aircraft defects in air transport, the battery system is required to deliver high output and generate a high capacity to ensure sufficient braking distance or driving distance for an emergency landing. On the other hand, it is also essential that the system can meet the requirements for improved lifespan performance under general normal operating conditions, such as the periodic flight of air transport.

[0004] On the other hand, lithium-ion batteries, which use lithium ions as a medium, are being considered as secondary batteries. Generally, lithium-ion batteries consist of a positive electrode containing a positive electrode active material, a negative electrode containing a negative electrode active material, an electrolyte that acts as a medium for transferring lithium ions, and a separator. In this case, carbon-based active materials and silicon-based active materials can be used as the negative electrode active material. In addition, lithium transition metal oxides such as lithium cobalt oxide (LiCoO2), lithium nickel oxide (LiNiO2), and lithium nickel-cobalt-manganese composite transition metal oxides can be used as the positive electrode active material.

[0005] In this context, when applying battery systems to means of transportation such as automobiles, trains, and air transport, high output, high energy density, and excellent lifespan are required. In particular, during sudden braking of automobiles and trains, and emergency landings of air transport, high output must be maintained over a long period of time for stable stopping or landing. In this regard, carbon-based active materials are mainly considered as negative electrode active materials due to their high lifespan, but they have difficulty in providing the output required during stopping or emergency landing. On the other hand, methods using silicon-based active materials, which have a higher capacity than carbon-based active materials, are considered, but silicon-based active materials have problems in terms of lifespan due to the degree of volume expansion and contraction caused by lithium insertion / deinsertion, resulting in cracking of the SEI coating and deterioration of electrolyte side reactions, thus failing to meet the above requirements.

[0006] Therefore, there is an urgent need to develop a battery system that can deliver high output and high energy for extended periods during emergencies such as the suspension or emergency landing of a means of transport, while also possessing excellent lifespan. [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] One objective of the present invention is to provide a battery system for a means of transport that can exert high output and high energy for an extended period of time when the means of transport stops or makes an emergency landing due to an abnormal situation.

[0008] Another object of the present invention relates to a control method for a battery system for a means of transport that can exert high output and high energy for a long period of time when the means of transport stops or makes an emergency landing due to an abnormal situation. [Means for solving the problem]

[0009] [1] The present invention relates to a battery system for a moving means, wherein the battery system includes a secondary battery and a battery management device. The secondary battery includes a positive electrode containing a positive electrode active material, a negative electrode containing a negative electrode active material, a separator, and an electrolyte. The negative electrode active material includes a silicon-based active material and a carbon-based active material. The battery management device includes a diagnostic unit and a control unit. The diagnostic unit diagnoses the normal operation status or abnormal operation status of the moving means. The control unit controls the battery system to charge and discharge the secondary battery in a first driving mode when the diagnostic unit diagnoses the normal operation status, and controls the battery system to charge and discharge the secondary battery in a second driving mode when the diagnostic unit diagnoses the abnormal operation status. In the first driving mode, the battery system is controlled to charge and discharge the secondary battery for one cycle or more within a first driving voltage range V 1a ~V 1b . In the first driving voltage range, the upper limit V 1b is a value determined from 4.1 V to 4.6 V, and the lower limit V 1a is a value determined from 2.8 V or more and less than V 1b . In the second driving mode, the battery system is controlled to charge and discharge the secondary battery for one cycle or more within a second driving voltage range V 2a ~V 2b . In the second driving voltage range, the upper limit V 2b is a value determined from 4.1 V to 4.6 V, and the lower limit V 2a is a value determined from less than 2.8 V. A battery system for a moving means is provided.

[0010] [2] The present invention provides the battery system for a moving means according to [1], wherein the silicon-based active material includes at least one kind of silicon-based core particles selected from the group consisting of silicon (Si), silicon oxide (SiO x , 0 < x < 2), silicon-carbon composite, and silicon-metal alloy.

[0011] [3] The present invention provides the battery system for a moving means according to any one of [1] and [2], wherein the silicon-based core particles are composed of a silicon-carbon composite.

[0012] [4] The present invention provides a battery system for a means of transport according to any one of [1] to [3], wherein the silicon-based active material further comprises a carbon coating layer located on the silicon-based core particles.

[0013] [5] The present invention provides a battery system for a means of transport according to any one of [1] to [4] above, wherein the carbon-based active material comprises at least one selected from the group consisting of graphite, hard carbon, soft carbon, carbon black, graphene, and fibrous carbon.

[0014] [6] The present invention provides a battery system for a means of transport according to any one of [1] to [5], wherein the weight ratio of the silicon-based active material and the carbon-based active material is 1:99 to 40:60.

[0015] [7] The present invention provides a battery system for a means of transport according to any one of [1] to [6] above, wherein the positive electrode active material comprises a lithium nickel oxide.

[0016] [8] The present invention provides a battery system for a means of transport according to any one of [1] to [7] above, wherein the lithium nickel oxide is a compound represented by the following chemical formula 1.

[0017] [Chemical formula 1] Li a1 Ni b1 Co c1 M 1 d1 M 2 e1 O2

[0018] In the above chemical formula 1, M 1 M is Mn, Al, or a combination of these. 2a1, b1, c1, d1, and e1 are the atomic fractions of independent elements, where 0.8 ≤ a1 ≤ 1.3 and 0.8 ≤ b1 < 1. <c1<0.2、0<d1<0.2、0≦e1≦0.1であり、b1+c1+d1+e1=1である。

[0019] [9] The present invention provides a battery system for a means of transport according to any one of [1] to [8], wherein the lithium nickel oxide is in the form of at least one single particle consisting of one nodule and a pseudo-single particle which is a composite of 30 or fewer nodules.

[0020]

[10] The present invention relates to the V 1a The present invention provides a battery system for a means of transport described in any one of [1] to [9] above, wherein the voltage is set to a value between 2.8V and 3.0V.

[0021]

[11] The present invention relates to the V 2a The present invention provides a battery system for a means of transport described in any one of [1] to

[10] above, wherein the voltage is set to a value between 2.4V and 2.7V.

[0022]

[12] The present invention relates to the V 1a V 2a The present invention provides a battery system for a means of transport according to any one of [1] to

[11] above, wherein the ratio of is 0.9 or less.

[0023]

[13] The present invention also relates to a control method for a battery system for a means of transport, comprising the steps of: providing a battery system comprising a secondary battery and a battery management device including a diagnostic unit and a control unit; the diagnostic unit diagnosing the normal operation status or abnormal operation status of the means of transport; the control unit charging and discharging the secondary battery in a first drive mode when the diagnostic unit diagnoses the normal operation status; and the control unit charging and discharging the secondary battery in a second drive mode when the diagnostic unit diagnoses the abnormal operation status, wherein the secondary battery comprises a positive electrode including a positive electrode active material, a negative electrode including a negative electrode active material, a separator, and an electrolyte, the negative electrode active material comprising a silicon-based active material and a carbon-based active material, and in the first drive mode, the secondary battery is driven in a first drive voltage range V 1a ~V 1b The battery system is controlled to charge and discharge for one or more cycles, and in the first drive voltage range, the upper limit V 1b This value was determined from 4.1V to 4.6V, with the lower limit V 1a The voltage is 2.8V or higher. 1b A value determined from among those less than or equal to, and in the second drive mode, the secondary battery is set to the second drive voltage range V 2a ~V 2b The battery system is controlled to charge and discharge for one or more cycles, and in the second drive voltage range, the upper limit V 2b This value was determined from 4.1V to 4.6V, with the lower limit V 2a The present invention provides a control method for a battery system for a means of transport, wherein the voltage is a value determined from among those less than 2.8V. [Effects of the Invention]

[0024] The present invention provides a battery system for a means of transport including a secondary battery and a battery management device, and a method for controlling the same. The battery management device includes a diagnostic unit capable of diagnosing the normal or abnormal operating conditions of a means of transport such as an automobile, train, or air transport, and a control unit capable of adjusting the charge / discharge range of the secondary battery according to the diagnosis of the diagnostic unit. The secondary battery includes a positive electrode containing a positive electrode active material and a negative electrode containing a silicon-based active material and a carbon-based active material as negative electrode active materials. In the battery system for a means of transport according to the present invention, when the means of transport is operating normally, the diagnostic unit and the first drive mode of the control unit set the lower limit of the drive voltage range to a value of 2.8V or higher and charge / discharge the secondary battery. In the case of abnormal operating conditions of the means of transport, a situation requiring an emergency stop, or an emergency situation requiring an emergency landing, the diagnostic unit and the second drive mode of the control unit set the lower limit of the drive voltage range to a value of less than 2.8V and charge / discharge the secondary battery. The battery system for a means of transport according to the present invention includes a silicon-based active material and a carbon-based active material, which increases the duration of high output maintenance during discharge in the second drive mode, thereby enabling stable sudden stops, emergency landings, and the like. [Modes for carrying out the invention]

[0025] The terms and words used in this specification and in the claims should not be interpreted in a manner limited to their ordinary or dictionary meanings, but rather in a manner consistent with the technical idea of ​​the present invention, in accordance with the principle that inventors may appropriately define the concepts of terms in order to best describe their invention.

[0026] In this specification, terms such as “includes,” “equip,” or “have” are intended to specify the presence of implemented features, figures, steps, components, or combinations thereof, and should be understood not to preemptively exclude the presence or possibility of adding one or more other features, figures, steps, components, or combinations thereof.

[0027] In this invention, "single particle" refers to a particle consisting of one single nodule. In this invention, "pseudo-single particle" refers to a composite particle formed from 30 or fewer nodules.

[0028] In the present invention, "nodule" means a particle unit body that constitutes a single particle or a pseudo-single particle. The nodule may be a single crystal without crystalline grain boundaries, or a polycrystalline material in which grain boundaries appear to be absent when observed with a scanning electron microscope (SEM) at a field of view of 5,000 to 20,000 times. The average particle size of the nodule can be measured from the arithmetic mean of the particle sizes of each nodule measured using a scanning electron microscope (SEM).

[0029] In this invention, "secondary particle" refers to a particle formed by the aggregation of several tens to hundreds of primary particles. More specifically, a secondary particle is an aggregate of 40 or more primary particles.

[0030] The present invention will be described in detail below.

[0031] <Battery systems for transportation> The present invention relates to a battery system for means of transport. The means of transport may include automobiles, trains, and / or air transport. More specifically, the present invention relates to a battery system for air transport. More specifically, the present invention relates to a battery system for urban air mobility (UAM). The battery system for means of transport according to the present invention is not only suitable for repeated travel along a set route (e.g., takeoff, flight, and landing), but can also exert high output and high energy in abnormal situations requiring sudden stops, emergency landings, etc., thereby contributing to improved safety of air transport.

[0032] Specifically, the battery system includes a secondary battery and a battery management device, the secondary battery includes a positive electrode containing a positive electrode active material, a negative electrode containing a negative electrode active material, a separator, and an electrolyte, the negative electrode active material includes a silicon-based active material and a carbon-based active material, the battery management device includes a diagnostic unit and a control unit, the diagnostic unit diagnoses the normal or abnormal operation status of the moving means, the control unit controls the battery system to charge and discharge the secondary battery in a first drive mode when the diagnostic unit diagnoses the normal operation status, and to charge and discharge the secondary battery in a second drive mode when the diagnostic unit diagnoses the abnormal operation status, and in the first drive mode, the secondary battery is driven within a first drive voltage range V 1a ~V 1b The battery system is controlled to charge and discharge for one or more cycles, and in the first drive voltage range, the upper limit V 1b This value was determined from 4.1V to 4.6V, with the lower limit V 1a The voltage is 2.8V or higher. 1b A value determined from among those less than or equal to, and in the second drive mode, the secondary battery is set to the second drive voltage range V 2a ~V 2b The battery system is controlled to charge and discharge for one or more cycles, and in the second drive voltage range, the upper limit V 2b This value was determined from 4.1V to 4.6V, with the lower limit V 2a The battery system for a means of transport is provided, and the voltage is a value determined from among those less than 2.8V.

[0033] The present invention provides a battery system for a means of transport including a secondary battery and a battery management device, and a method for controlling the same. The battery management device includes a diagnostic unit capable of diagnosing the normal or abnormal operating conditions of the means of transport, and a control unit capable of adjusting the charge / discharge range of the secondary battery according to the diagnosis of the diagnostic unit. The secondary battery includes a positive electrode containing a positive electrode active material and a negative electrode containing a silicon-based active material and a carbon-based active material as negative electrode active materials. In the battery system for a means of transport according to the present invention, when the means of transport is operating normally, the diagnostic unit and the first drive mode of the control unit set the lower limit of the drive voltage range to a value of 2.8V or higher and charge / discharge the secondary battery. In the case of abnormal operating conditions of the means of transport, a situation requiring a sudden stop, or an emergency situation requiring an emergency landing, the diagnostic unit and the second drive mode of the control unit set the lower limit of the drive voltage range to a value of less than 2.8V and charge / discharge the secondary battery. The battery system for a means of transport according to the present invention includes a silicon-based active material and a carbon-based active material, which increases the duration of high output maintenance during discharge in the second drive mode, thereby enabling stable sudden stops, emergency landings, and the like.

[0034] (1) Secondary battery The battery system according to the present invention includes a secondary battery. Specifically, the secondary battery may be a lithium secondary battery.

[0035] The secondary battery includes a positive electrode, a negative electrode, a separator, and an electrolyte. More specifically, the secondary battery may include a positive electrode, a negative electrode facing the positive electrode, a separator interposed between the positive electrode and the negative electrode, and an electrolyte. The lithium secondary battery can be manufactured by housing an electrode assembly including the positive electrode, a negative electrode facing the positive electrode, and a separator interposed between the positive electrode and the negative electrode in a battery case, and then injecting an electrolyte.

[0036] 1) Positive electrode The positive electrode includes a positive electrode active material.

[0037] The positive electrode active material is a compound capable of reversible intercalation and deintercalation, and is not particularly limited as long as it is a positive electrode active material used in this field. Specifically, the positive electrode active material is a layered compound such as lithium cobalt oxide (LiCoO2) or lithium nickel oxide (LiNiO2), or a compound substituted with one or more transition metals; lithium iron oxide such as LiFe3O4; lithium iron phosphorus oxide such as LiFePO4; chemical formula Li 1+c1 Mn 2-c1 Lithium manganese oxides such as O4 (0 ≤ c1 ≤ 0.33), LiMnO3, LiMn2O3, LiMnO2; lithium copper oxide (Li2CuO2); vanadium oxides such as LiV3O8, V2O5, Cu2V2O7; chemical formula LiNi 1-c2 M c2 Ni-site type lithium nickel oxide represented as O2 (where M is at least one selected from the group consisting of Co, Mn, Al, Cu, Fe, Mg, B, and Ga, satisfying 0.01 ≤ c2 ≤ 0.3); chemical formula LiMn 2-c3 M c3 Lithium manganese composite oxides represented by O2 (where M is at least one selected from the group consisting of Co, Ni, Fe, Cr, Zn, and Ta, satisfying 0.01 ≤ c3 ≤ 0.1) or Li2Mn3MO8 (where M is at least one selected from the group consisting of Fe, Co, Ni, Cu, and Zn); are examples, but are not limited to these. The positive electrode may also be a Li metal positive electrode.

[0038] Specifically, the positive electrode active material may contain a lithium nickel-based oxide.

[0039] More specifically, the lithium nickel oxide may include a compound represented by the following chemical formula 1.

[0040] [Chemical formula 1] Li a1 Ni b1 Co c1 M 1 d1 M2 e1 O2

[0041] In the above chemical formula 1, M 1 M is Mn, Al, or a combination of these. 2 a1, b1, c1, d1, and e1 are the atomic fractions of independent elements, where 0.8 ≤ a1 ≤ 1.3 and 0.8 ≤ b1 < 1. <c1<0.2、0<d1<0.2、0≦e1≦0.1であり、b1+c1+d1+e1=1である。

[0042] Said M 1 This may be Mn, Al, or a combination thereof, preferably Mn, or Mn and Al.

[0043] Said M 2 is one or more selected from the group consisting of Zr, W, Y, Ba, Ca, Ti, Mg, Ta, and Nb, preferably one or more selected from the group consisting of Zr, Y, Mg, and Ti, and more preferably Zr, Y, or a combination thereof. 2 While elements are not essential, when present in appropriate amounts, they can promote grain growth during firing and improve the stability of the crystal structure.

[0044] The above a1 represents the molar ratio of lithium in the lithium transition metal oxide, and may be 0.8 ≤ a1 ≤ 1.3, 0.9 ≤ a1 ≤ 1.3, or 1.0 ≤ a1 ≤ 1.2. When the molar ratio of lithium satisfies the above range, the crystal structure of the lithium transition metal oxide can be stably formed.

[0045] The aforementioned b1 represents the molar ratio of nickel to the total metal excluding lithium in the lithium transition metal oxide, and may be 0.8 ≤ b1 < 1, 0.82 ≤ b1 < 1, 0.83 ≤ b1 < 1, or 0.85 ≤ b1 < 1. When the molar ratio of nickel satisfies the above range, a high energy density is observed, and high capacity can be achieved.

[0046] c1 represents the molar ratio of cobalt among all the metals excluding lithium in the lithium transition metal oxide, and may be 0 < c1 < 0.2, 0 < c1 < 0.18, or 0.01 ≤ c1 ≤ 0.17. When the molar ratio of cobalt satisfies the above range, good resistance characteristics and output characteristics can be realized.

[0047] d1 represents the molar ratio of the M 1 element among all the metals excluding lithium in the lithium transition metal oxide, and may be 0 < d1 < 0.2, 0 < d1 < 0.18, or 0.01 ≤ d1 ≤​​​​​​​​​​​​​​​​​​​When the lithium nickel oxide is in the form of at least one of the single particles and pseudo-single particles described above, the average particle size D of the lithium nickel oxide 50 The average particle size D of the positive electrode active material may be 10 μm or less, 8 μm or less, 7 μm or less, or 5 μm or less, for example, 0.5 μm to 10 μm, preferably 1 μm to 8 μm, more preferably 2 μm to 7 μm, and more preferably 3 μm to 5 μm. 50 If the above range is met, the increase in resistance can be minimized. Specifically, lithium nickel oxides in single-particle and / or pseudo-single-particle form may have fewer interfaces between primary particles that serve as diffusion pathways for lithium ions within the particle, so the D of the lithium nickel oxide within the above range 50 By adjusting this, the diffusion distance of lithium ions within the particle can be minimized, thereby suppressing the increase in resistance and improving output performance.

[0052] The positive electrode may include a positive electrode current collector and a positive electrode active material layer disposed on at least one side of the positive electrode current collector. In this case, the positive electrode active material may be contained within the positive electrode active material layer.

[0053] The positive electrode current collector is not particularly limited as long as it does not cause chemical changes in the battery and has high conductivity. Specifically, the positive electrode current collector may contain at least one selected from the group consisting of copper, stainless steel, aluminum, nickel, titanium, calcined carbon, and aluminum-cadmium alloy, preferably aluminum.

[0054] The thickness of the positive electrode current collector is typically between 3 μm and 500 μm.

[0055] The positive electrode current collector may have its surface textured to enhance the bonding force of the positive electrode active material. For example, the positive electrode current collector can be used in various forms such as film, sheet, foil, mesh, porous material, foam, or nonwoven fabric.

[0056] The positive electrode active material layer may be arranged on at least one side of the positive electrode current collector. Specifically, the positive electrode active material layer may be arranged on one or both sides of the positive electrode current collector.

[0057] The positive electrode active material layer may contain the positive electrode active material described above.

[0058] The positive electrode active material may be present in the positive electrode active material layer in an amount of 80% to 99% by weight, specifically 90% to 98% by weight.

[0059] The positive electrode active material layer may further selectively contain a binder and / or a conductive material along with the positive electrode active material.

[0060] The binder is a component that assists in the binding of the active material to the conductive material and to the current collector, and specifically may contain at least one selected from the group consisting of polyvinylidene fluoride, polyvinyl alcohol, carboxymethylcellulose (CMC), starch, hydroxypropylcellulose, regenerated cellulose, polyvinylpyrrolidone, polytetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene polymer (EPDM), sulfonated EPDM, styrene-butadiene rubber, and fluororubber, preferably polyvinylidene fluoride.

[0061] The binder may be included in the positive electrode active material layer in an amount of 1% to 20% by weight, preferably 1.2% to 10% by weight, from the viewpoint of ensuring sufficient binding force between components such as the positive electrode active material.

[0062] The conductive material is used to assist and improve the conductivity of a secondary battery and is not particularly limited as long as it does not cause chemical changes and is conductive. Specifically, the positive electrode conductive material may contain at least one selected from the group consisting of graphite such as natural graphite or artificial graphite; carbon black such as carbon black, acetylene black, Ketjen black, channel black, furnace black, lamp black, and thermal black; conductive fibers such as carbon fibers and metal fibers; conductive tubes such as carbon nanotubes; fluorocarbons; metal powders such as aluminum and nickel powder; conductive whiskers such as zinc oxide and potassium titanate; conductive metal oxides such as titanium oxide; and polyphenylene derivatives, and preferably contains carbon nanotubes in order to improve conductivity.

[0063] The conductive material may be included in the positive electrode active material layer in an amount of 1% to 20% by weight, preferably 1.2% to 10% by weight, in order to ensure sufficient electrical conductivity.

[0064] The thickness of the positive electrode active material layer may be 5 μm to 500 μm, preferably 20 μm to 200 μm.

[0065] The positive electrode can be manufactured by coating a positive electrode slurry containing a positive electrode active material and selectively a binder, conductive material, and a solvent for forming the positive electrode slurry (e.g., NMP) onto the positive electrode current collector, followed by drying and rolling.

[0066] 2) Negative electrode The negative electrode faces the positive electrode.

[0067] The aforementioned negative electrode contains a negative electrode active material.

[0068] The negative electrode active material includes a silicon-based active material and a carbon-based active material.

[0069] Furthermore, the silicon-based active material has a larger irreversible capacity compared to the carbon-based active material, and at the discharge end, the negative electrode potential rises first, the lower end potential of the positive electrode is no longer used, and the unused low-potential section of the positive electrode increases. The battery system according to the present invention incorporates a silicon-based active material in the negative electrode active material, thereby allowing the silicon-based active material with a large irreversible capacity to reach the lower voltage limit (V) in the second drive mode. 2a ) This allows the device to exhibit high output rather than following the lower end potential of the positive electrode. Therefore, according to the present invention, when an abnormal operating situation occurs in a means of transport, such as a sudden stop or emergency landing, the above-mentioned features allow high output to be maintained for a long period of time at the lower end of the negative electrode's remaining capacity SOC. When only carbon-based active material is used as the negative electrode active material, the potential of the negative electrode does not rise to the point where it uses the lower end potential of the positive electrode at the discharge end of the carbon-based active material, which has low irreversible capacity. As a result, the voltage of the positive electrode changes rapidly, and the entire voltage range in the section with very high resistance is used. This has an unfavorable effect on the use of high output.

[0070] On the other hand, silicon-based active materials may have unfavorable effects on lifespan performance, such as volume expansion during charging and discharging. Therefore, the negative electrode active material according to the present invention uses a carbon-based active material that exhibits excellent lifespan performance in combination with a silicon-based active material. In other words, the battery system according to the present invention adjusts the voltage range in each driving mode so that the stable battery system driving capability of the carbon-based active material is mainly exhibited when the means of transport is moving smoothly (first driving mode), and the high output effect of the silicon-based active material is exhibited in emergency situations (second driving mode).

[0071] The aforementioned silicon-based active material is silicon (Si), silicon oxide (SiO x、(0 < x < 2), at least one silicon-based core particle selected from the group consisting of a silicon-carbon composite and a silicon-metal alloy. More specifically, the silicon-based core particle may consist of a silicon-carbon composite, which is preferable in terms of exhibiting a high theoretical capacity and high energy density, and the effect of exhibiting high output and high energy in an emergency can be improved by the diagnosis and control of the battery management device described later.

[0072] The silicon-based active material may further contain a metal doped into the silicon-based core particle. The metal may be introduced to reduce the irreversible phase of the silicon-based core particle and improve efficiency.

[0073] The metal may contain at least one metal selected from the group consisting of Li, Mg, Ca, and Al. Specifically, from the point that it is possible to achieve an excellent level in terms of volume expansion control, damage prevention, and improvement effect of initial efficiency of the silicon-based active material, etc., at least one metal selected from the group consisting of Li and Mg, more specifically, Mg may be included. The weight of the metal may be included in the silicon-based active material at a content of 1 wt% to 30 wt%, specifically 5 wt% to 20 wt%, but is not particularly limited thereto.

[0074] The silicon-based active material may further contain a carbon coating layer disposed on the surface. The carbon coating layer can function as a protective layer that suppresses the volume expansion of the silicon-based active material and prevents side reactions with the electrolyte. The carbon coating layer may be disposed, for example, on the silicon-based core particle. The carbon coating layer may be included in the silicon-based active material at 0.1 wt% to​​​The carbon coating layer may be an amorphous carbon coating layer. Specifically, the carbon coating layer can be formed by chemical vapor deposition (CVD) using at least one hydrocarbon gas selected from the group consisting of methane, ethane, and acetylene.

[0076] The average particle size (D) of the silicon-based active material 50 The particle size may be 0.1 μm to 15 μm, more preferably 0.1 μm to 10 μm, in order to ensure the structural stability of the active material during charging and discharging, prevent the problem of excessive volume expansion / contraction due to excessively large particle size, and prevent the problem of reduced initial efficiency due to excessively low particle size.

[0077] The carbon-based active material may include at least one selected from the group consisting of graphite, hard carbon, soft carbon, carbon black, graphene, and fibrous carbon, and specifically may include graphite. The graphite may be artificial graphite, natural graphite, or a mixture thereof.

[0078] The average particle size (D) of the carbon-based active material 50 The thickness of the ) may be 10 μm to 30 μm, preferably 15 μm to 25 μm, in order to ensure structural stability during charging and discharging and to reduce side reactions with the electrolyte.

[0079] The weight ratio of the silicon-based active material and the carbon-based active material may be 1:99 to 40:60, specifically 1:99 to 20:80, more specifically 3:97 to 15:85, and more specifically 8:92 to 15:85. The above range is preferable because it allows for securing the capacity and improving the lifespan performance required during normal operation of the air transport means, while simultaneously enabling the output of high power and high energy in emergency situations.

[0080] The negative electrode may include a negative electrode current collector and a negative electrode active material layer disposed on at least one side of the negative electrode current collector. In this case, the negative electrode active material may be contained in the negative electrode active material layer.

[0081] The negative electrode current collector is not particularly limited as long as it does not cause chemical changes in the battery and has high conductivity. Specifically, the negative electrode current collector may be made of copper, stainless steel, aluminum, nickel, titanium, calcined carbon, copper or stainless steel with a surface treatment of carbon, nickel, titanium, silver, etc., or aluminum-cadmium alloy.

[0082] The negative electrode current collector typically has a thickness of 3 μm to 500 μm.

[0083] The negative electrode current collector may have its surface textured to enhance the bonding force of the negative electrode active material. For example, the negative electrode current collector can be used in various forms such as film, sheet, foil, mesh, porous material, foam, or nonwoven fabric.

[0084] The negative electrode active material layer may be disposed on at least one side of the negative electrode current collector, specifically on one or both sides of the negative electrode current collector.

[0085] The negative electrode active material may be included in the negative electrode active material layer in an amount of 60% to 99% by weight, preferably 75% to 95% by weight.

[0086] Further explanation regarding the positive electrode active material has been given above and will therefore be omitted.

[0087] The negative electrode active material layer may further include a binder and / or a conductive material together with the negative electrode active material.

[0088] The binder is used to improve the performance of the battery by improving the adhesion between the negative electrode active material layer and the negative electrode current collector, and may contain, for example, at least one selected from the group consisting of polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-co-HFP), polyvinylidene fluoride (PVDF), polyacrylonitrile, polymethyl methacrylate, polyvinyl alcohol, carboxymethylcellulose (CMC), starch, hydroxypropylcellulose, regenerated cellulose, polyvinylpyrrolidone, polytetrafluoroethylene, polyethylene, polypropylene, polyacrylic acid, ethylene-propylene-diene monomer (EPDM), sulfonated EPDM, styrene-butadiene rubber (SBR), fluororubber, and substances in which the hydrogen of these substances is substituted with Li, Na, or Ca, or may contain various copolymers thereof.

[0089] The binder may be included in the negative electrode active material layer in an amount of 0.5% to 10% by weight, preferably 1% to 5% by weight.

[0090] The conductive material is not particularly limited as long as it does not cause a chemical change in the battery and is conductive. Examples include graphite such as natural graphite or artificial graphite; carbon black such as carbon black, acetylene black, Ketjen black, channel black, furnace black, lamp black, and thermal black; conductive fibers such as carbon fibers and metal fibers; conductive tubes such as carbon nanotubes; fluorocarbons; metal powders such as aluminum and nickel powder; conductive whiskers such as zinc oxide and potassium titanate; conductive metal oxides such as titanium oxide; and conductive materials such as polyphenylene derivatives.

[0091] The conductive material may be included in the negative electrode active material layer in an amount of 0.5% to 10% by weight, preferably 1% to 5% by weight.

[0092] The thickness of the negative electrode active material layer may be 10 μm to 200 μm, preferably 20 μm to 150 μm.

[0093] The negative electrode can be manufactured by coating at least one surface of a negative electrode current collector with a negative electrode slurry containing a negative electrode active material, a binder, a conductive material, and / or a solvent for forming the negative electrode slurry, followed by drying and rolling.

[0094] The solvent for forming the negative electrode slurry may include, for example, at least one selected from the group consisting of distilled water, NMP (N-methyl-2-pyrrolidone), ethanol, methanol, and isopropyl alcohol, preferably distilled water, in order to facilitate the dispersion of the negative electrode active material, binder, and / or conductive material. The solid content of the negative electrode slurry may be 30% to 80% by weight, specifically 40% to 70% by weight.

[0095] 3) Separator The separator can be interposed between the positive electrode and the negative electrode.

[0096] Furthermore, the separator may be a conventional porous polymer film, such as a porous polymer film made from polyolefin polymers like ethylene monopolymer, propylene monopolymer, ethylene / butene copolymer, ethylene / hexene copolymer, and ethylene / methacrylate copolymer, used alone or in a laminated configuration. Alternatively, a conventional porous nonwoven fabric, such as a nonwoven fabric made from high-melting-point glass fibers or polyethylene terephthalate fibers, may be used, but is not limited to these. In addition, a coated separator containing ceramic components or polymeric substances may be used to ensure heat resistance or mechanical strength, and may be used selectively as a single-layer or multi-layer structure.

[0097] 4) Electrolyte The electrolyte may be a non-aqueous electrolyte.

[0098] Examples of electrolytes used in the present invention include, but are not limited to, organic liquid electrolytes, inorganic liquid electrolytes, solid polymer electrolytes, gel-type polymer electrolytes, solid inorganic electrolytes, and molten inorganic electrolytes that can be used in the manufacture of secondary batteries.

[0099] Specifically, the electrolyte may include an organic solvent and a lithium salt.

[0100] The lithium salt can be any compound capable of providing lithium ions for use in lithium secondary batteries, and is not particularly limited. Specifically, the lithium salt can be LiPF6, LiClO4, LiAsF6, LiBF4, LiSbF6, LiAlO4, LiAlCl4, LiCF3SO3, LiC4F9SO3, LiN(C2F5SO3)2, LiN(C2F5SO2)2, LiN(CF3SO2)2, LiCl, LiI, or LiB(C2O4)2. The concentration of the lithium salt is preferably within the range of 0.1M to 2.0M. When the concentration of the lithium salt falls within the above range, the electrolyte has appropriate conductivity and viscosity, exhibiting excellent electrolyte performance and allowing lithium ions to move effectively.

[0101] The organic solvent may contain at least one selected from linear carbonates, cyclic carbonates, linear esters, cyclic esters, ethers, glymes, and nitriles.

[0102] The linear carbonate may include at least one selected from the group consisting of dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate, ethyl methyl carbonate (EMC), methyl propyl carbonate, and ethyl propyl carbonate.

[0103] The cyclic carbonate may include at least one selected from the group consisting of ethylene carbonate (EC), propylene carbonate (PC), 1,2-butylene carbonate, 2,3-butylene carbonate, 1,2-pentylene carbonate, and 2,3-pentylene carbonate.

[0104] Specific examples of the linear esters mentioned above include, but are not limited to, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, and butyl propionate.

[0105] Specific examples of the aforementioned cyclic esters include, but are not limited to, γ-butyrolactone, γ-valerolactone, γ-caprolactone, σ-valerolactone, and ε-caprolactone.

[0106] Specific examples of the aforementioned ethers include, but are not limited to, dimethyl ether, diethyl ether, dipropyl ether, methyl ethyl ether, methyl propyl ether, ethyl propyl ether, 1,3-dioxolane (DOL), and 2,2-bis(trifluoromethyl)-1,3-dioxolane (TFDOL).

[0107] Specific examples of the aforementioned glyme include, but are not limited to, dimethoxyethane (glyme, DME), diethoxyethane, diglyme, triglyme, and tetraglyme (TEGDME).

[0108] Specific examples of the aforementioned nitriles include, but are not limited to, acetonitrile, propionitrile, butyronitrile, valeronitrile, caprylonitrile, heptanenitrile, cyclopentanecarbonile, cyclohexanecarbonile, 2-fluorobenzonitrile, 4-fluorobenzonitrile, difluorobenzonitrile, trifluorobenzonitrile, phenylacetonitrile, 2-fluorophenylacetonitrile, and 4-fluorophenylacetonitrile.

[0109] The electrolyte may further contain additives along with the lithium salt and organic solvent.

[0110] The aforementioned additive may include at least one selected from the group consisting of vinylethylene carbonate, propanesultone, LiBF4 (Lithium tetrafluoroborate), LiODFB (Lithium difluoro(oxalato)borate), 1,3,6-HTCN (Hexane Tri-Cyanide), and NaO2 (Sodium superoxide), specifically, fluoroethylene carbonate, difluoroethylene carbonate, vinylethylene carbonate, propanesultone, LiBF4 (Lithium tetrafluoroborate), LiODFB (Lithium difluoro(oxalato)borate), 1,3,6-HTCN (Hexane Tri-Cyanide), succinonitrile, 1,4-dicyano-2-butyne, adipionitrile, lithium difluorophosphate (LiPO2F2), and NaO2 (Sodium superoxide).

[0111] The aforementioned other additives may be included in the electrolyte in an amount of 0.1% to 20% by weight, specifically 1% to 10% by weight, but are not limited thereto.

[0112] The external shape of the secondary battery of the present invention is not particularly limited, but it may be cylindrical, rectangular, pouch-shaped, or coin-shaped, using a can.

[0113] The secondary batteries may be multiple. For example, the battery system may include a battery module, and the battery module may include one or more secondary batteries.

[0114] (2)Battery management device A Battery Management System (BMS) can manage and / or control the state and / or operation of the secondary battery.

[0115] Specifically, the battery management device may include a diagnostic unit and a control unit.

[0116] The diagnostic unit can diagnose, determine, and / or detect the normal or abnormal operating status of the means of transport. Normal operating status of the means of transport may mean, for example, a situation where there are no particular problems with takeoff from the departure point, flight to the destination, and landing at the destination for an air transport, or a situation where a car, train, etc., can travel smoothly at the intended speed or steering direction. Abnormal operating status of the means of transport may mean a situation where normal operation of the means of transport is difficult, and without limitation, a situation where further normal operation is impossible due to an aircraft defect, battery system defect, adverse weather, or patient outbreak in an air transport, requiring measures such as high-speed flight or emergency landing, or a situation where a car, train, etc., has a defect or requires an emergency stop due to other external circumstances. The diagnosis of abnormal operating status of the means of transport is not particularly limited, and may be performed by the diagnostic unit receiving and determining signals from abnormal operating status outside the battery system, or by the diagnostic unit detecting or analyzing abnormal operation of the battery management device.

[0117] The control unit can manage and / or control the state and / or operation of the secondary battery, including the range of the drive voltage and the range of the State of Charge (SOC) during charging and discharging of the secondary battery.

[0118] Specifically, the control unit charges and discharges the secondary battery in the first drive mode when the diagnostic unit diagnoses the normal operating status.

[0119] In the first drive mode, the secondary battery is set to a first drive voltage range V 1a ~V 1b The battery system can be controlled to charge and discharge for one or more cycles. In this case, the upper limit V is set within the first drive voltage range. 1b This value was determined from 4.1V to 4.6V, with the lower limit V 1a The voltage is 2.8V or higher. 1b The value may be determined from among those less than or equal to the specified value.

[0120] The first drive mode minimizes the use of silicon-based active material and allows carbon-based active material to function as the main active material by enabling charging and discharging of the secondary battery within the first drive voltage range, thereby minimizing the degradation of the lifespan performance of the means of transport and enabling stable operation.

[0121] In the above first drive mode, upper limit V 1b This value may be determined from 4.1V to 4.6V, and more specifically, it may be determined from 4.1V to 4.3V.

[0122] In the first drive mode, the lower limit V 1a V is 2.8V or higher 1b The value may be determined from among those less than 2.8V, specifically from 2.8V to 3.0V, or more specifically from 2.8V to 2.9V.

[0123] In the first drive mode, the secondary battery is charged and discharged for one or more cycles within the first drive voltage range. If the number of charge-discharge cycles of the secondary battery is two or more, the V in each cycle 1a and V 1b They may be the same or different, as long as the aforementioned conditions are met.

[0124] Furthermore, the control unit charges and discharges the secondary battery in the second drive mode when the diagnostic unit diagnoses an abnormal operating condition.

[0125] In the second drive mode, the secondary battery is set to the second drive voltage range V 2a ~V 2b The battery system can be controlled to charge and discharge for one or more cycles. In this case, the upper limit V is set within the second drive voltage range. 2b This value was determined from 4.1V to 4.6V, with the lower limit V 2a This value may be determined from among those less than 2.8V.

[0126] In the second drive mode, charging and discharging of the secondary battery are performed within the second drive voltage range, and due to the high irreversible capacity of the silicon-based active material, the lower voltage limit (V) in the second drive mode is maintained. 2a ) This enables the device to exert high output without being subject to the lower end potential of the positive electrode. Therefore, according to the present invention, when an abnormal operating situation occurs in a means of transport that requires sudden stopping or emergency landing, the above-mentioned features allow the device to maintain high output at the lower end of the remaining capacity SOC of the negative electrode for a long period of time.

[0127] In the second drive mode described above, the upper limit V 2b This value may be determined from 4.1V to 4.6V, and more specifically, it may be determined from 4.1V to 4.3V.

[0128] In the second drive mode, the lower limit V 2a The value may be determined from among those less than 2.8V, a value determined from among those 2.7V or less, or a value determined from among those 2.6V or less. The lower limit V 2a This value may be determined from among those less than 2.8V, specifically from 2.0V to 2.7V, more specifically from 2.4V to 2.7V, even more specifically from 2.5V to 2.7V, and even more specifically from 2.5V to 2.6V.

[0129] In the second driving mode, the secondary battery is charged and discharged one or more cycles within the second driving voltage range. When the number of charge-discharge cycles of the secondary battery is 2 or more, V in each cycle 2a and V 2b may be the same or different as long as the above conditions are satisfied.

[0130] In the present invention, the ratio of V 1a to V 2a may be 0.95 or less, specifically 0.9 or less, and more specifically 0.89 or less.

[0131] In the battery system, in the first driving mode, in addition to the above conditions, the battery system may be controlled so that the secondary battery is charged and discharged one or more cycles so that the remaining capacity of the negative electrode is in the range of SOC 1a (unit: %) to SOC 1b (unit: %). At this time, the SOC 1a is a value set by the following mathematical formula 1, and the SOC 1b is a value that exceeds the SOC 1a value and is 100% or less.

[0132] [Mathematical formula 1] {(C Si ) / (C Si +C Carbon )}×100≦SOC 1a <100

[0133] In the mathematical formula 1, C Si is a value obtained by multiplying the theoretical capacity of the silicon-based active material (unit: mAh / g) by the weight of the silicon-based active material contained in the negative electrode active material (unit: g), and C Carbon is a value obtained by multiplying the theoretical capacity of the carbon-based active material (unit: mAh / g) by the weight of the carbon-based active material present in the negative electrode active material (unit: g).

[0134] The remaining capacity SOC of the negative electrode 1a is a value set by the mathematical formula 1. At this time, the formula "{(C Si ) / (C Si +CCarbon The formula is set to )} × 100 or more. The remaining capacity of the negative electrode SOC according to the above mathematical formula 1. 1a By setting this, the proportion of silicon-based active material used can be minimized under normal operating conditions of the transport mechanism, and the carbon-based active material can function as the main negative electrode active material. In other words, by minimizing the capacity contribution of the silicon-based active material, which exhibits unfavorable performance compared to the carbon-based active material in terms of lifespan, stable flight is possible under normal operating conditions of the transport mechanism without a decrease in lifespan.

[0135] More specifically, the aforementioned SOC 1a This may be a value set by the following mathematical formula 1-1. For example, the above-mentioned mathematical formula 1 can be replaced by the following mathematical formula 1-1.

[0136] [Mathematical formula 1-1] {(C Si ) / (C Si +C Carbon )} × 100 ≤ SOC 1a <[{(C Si ) / (C Si +C Carbon )} × 100] + x

[0137] In the above mathematical formula 1-1, x may be between 0 and 20, between 0 and 15, between 0 and 10, or between 0 and 5. The unit of x may be "%". The above SOC 1a When determined from the above range, the aforementioned effects can be fully achieved, the proportion of carbon-based active material used can be increased, and stable operation under normal operating conditions can be achieved.

[0138] The aforementioned SOC 1b The aforementioned SOC 1a The value may be greater than the given value but less than or equal to 100%, for example, it may be a value set from 90% to 100%, or more specifically, it may be 100%.

[0139] In the first drive mode, the remaining capacitance of the negative electrode is SOC 1a ~SOC 1bCharge and discharge the secondary battery for at least one cycle so that it falls within the specified range. If the number of charge and discharge cycles of the secondary battery is two or more, the State of Charge (SOC) for each cycle is measured. 1a and SOC 1b They may be the same or different, as long as the aforementioned conditions are met.

[0140] Furthermore, in the second drive mode, in addition to the conditions mentioned above, the remaining capacity of the negative electrode is SOC 2a (Unit: %) ~ SOC 2b The secondary battery may be charged and discharged for one or more cycles so that the SOC is within the range of (unit: %). 2a is 0% or more SOC 1a The value is less than the SOC 2b is SOC 2a The value can be greater than or equal to 100%.

[0141] In the aforementioned second drive mode, SOC 2a SOC is 0% or more 1a By setting the value to less than a certain level, the proportion of silicon-based active material used or the proportion of capacity it can exert can be increased. In other words, if the means of transport requires an emergency stop, high-speed flight, or emergency landing due to abnormal operation, the second drive mode can exert high power and high energy, and in particular, it can exert the high power required for emergency landings, as well as the capacity to reach the distance required for landing.

[0142] More specifically, the aforementioned SOC 2a This may be a value set by the following mathematical formula 2.

[0143] [Mathematical formula 2] 0 ≤ SOC 2a <{(C Si ) / (C Si +C Carbon )} × 100

[0144] In the above mathematical formula 2, C Si and C Carbon This is as defined in the above mathematical formula 1.

[0145] More specifically, the aforementioned SOC 2a The value may be set from 0% to 5%, for example, it may be 0%. 1b This value may be set from 90% to 100%, for example, it may be 100%. When it is within the above range, the capacity and output of the silicon-based active material can be easily achieved in emergency situations.

[0146] In the second drive mode, the remaining capacitance of the negative electrode is SOC 2a ~SOC 2b The secondary battery may be charged and discharged for one or more cycles so that it falls within the specified range. If the number of charge-discharge cycles of the secondary battery is two or more, the State of Charge (SOC) for each cycle is... 2a and SOC 2b They may be the same or different, as long as the aforementioned conditions are met.

[0147] The C rates in the first drive mode and the second drive mode may be 0.1C to 2C, specifically 0.5C to 1.5C, and more specifically 0.8C to 1.2C, independently of each other.

[0148] The means of transport is not particularly limited as long as it uses a battery as a power source, such as an automobile, train, monorail, ship, motorcycle, spacecraft, and / or air transport. Specifically, the means of transport may be an air transport. More specifically, the air transport may be Urban Air Mobility (UAM). The battery system according to the present invention is particularly suitably applicable to Urban Air Mobility, which must periodically take off, fly, and land along a set route.

[0149] Furthermore, the present invention provides a means of transport including the aforementioned battery system for a means of transport.

[0150] <Control method for battery systems used in transportation> Furthermore, the present invention provides a control method for a battery system for a means of transport. Specifically, the control method for the battery system for a means of transport may be the control method for the battery system for a means of transport described above.

[0151] Specifically, the control method for a battery system for a means of transport according to the present invention includes the steps of: providing a battery system including a secondary battery and a battery management device including a diagnostic unit and a control unit; the diagnostic unit diagnosing the normal operation status or abnormal operation status of the means of transport; the control unit charging and discharging the secondary battery in a first drive mode when the diagnostic unit diagnoses the normal operation status, and the control unit charging and discharging the secondary battery in a second drive mode when the diagnostic unit diagnoses the abnormal operation status; the secondary battery including a positive electrode containing a positive electrode active material, a negative electrode containing a negative electrode active material, a separator, and an electrolyte; the negative electrode active material including a silicon-based active material and a carbon-based active material; and in the first drive mode, the secondary battery is driven in a first drive voltage range V 1a ~V 1b The battery system is controlled to charge and discharge for one or more cycles, and in the first drive voltage range, the upper limit V 1b This value was determined from 4.1V to 4.6V, with the lower limit V 1a The voltage is 2.8V or higher. 1b A value determined from among those less than or equal to, and in the second drive mode, the secondary battery is set to the second drive voltage range V 2a ~V 2b The battery system is controlled to charge and discharge for one or more cycles, and in the second drive voltage range, the upper limit V 2b This value was determined from 4.1V to 4.6V, with the lower limit V 2a It is characterized by being a value determined from among those less than 2.8V.

[0152] The control method for a battery system for a means of transport according to the present invention is preferable because it has high lifespan performance during periodic operation (e.g., flight) and can provide high output for a long period of time in emergency situations, such as for sudden stops and emergency landings.

[0153] The battery system, the secondary battery and battery management device included therein, and the diagnostic and control units of the battery management device in the control method for the aforementioned battery system for a means of transport are as described above.

[0154] The present invention will be described in more detail below with reference to specific examples. However, the following examples are merely illustrative for understanding the present invention and are not intended to limit the scope of the invention. It will be obvious to those skilled in the art that various changes and modifications are possible within the scope of the described concept and technical idea, and it goes without saying that such variations and modifications fall within the scope of the appended claims.

[0155] <Examples and Comparative Examples> Example 1 1. Manufacturing of rechargeable batteries (1) Positive electrode As the positive electrode active material, Li[Ni 0.8 Co 0.1 Mn 0.1 O2 was prepared. The positive electrode active material is in the form of single particles or pseudo-single particles, with an average particle size (D 50 The particle size was 5 μm.

[0156] The cathode slurry was prepared by adding carbon nanotubes as the cathode active material and conductive material, and polyvinylidene fluoride (PVdF) as the binder in a weight ratio of 97:1:2, to N-methyl-2-pyrrolidone (NMP) as the solvent for forming the cathode slurry.

[0157] The positive electrode was manufactured by rolling the positive electrode slurry onto an aluminum current collector (roll press) and drying it in a vacuum oven at 130°C for 10 hours to form a positive electrode active material layer.

[0158] (2) Manufacturing of the negative electrode A silicon-carbon composite was prepared as the silicon-based active material, and graphite as the carbon-based active material. The silicon-carbon composite and graphite were mixed in a weight ratio of 6:94 to produce the negative electrode active material.

[0159] The negative electrode active material, styrene-butadiene rubber (SBR) as the negative electrode binder, carboxymethylcellulose (CMC) as a thickener, and carbon black as the negative electrode conductive material were mixed in a weight ratio of 96:2:1:1 and added to water as a solvent to produce a negative electrode slurry.

[0160] The negative electrode slurry produced as described above was applied to copper foil (thickness: 8 μm) as a negative electrode current collector, rolled (roll press), and dried in a vacuum oven at 130°C for 10 hours to form a negative electrode active material layer (thickness: μm), thereby producing the negative electrode.

[0161] (3) Manufacturing of secondary batteries A polyethylene separator was interposed between the negative electrode and positive electrode manufactured as described above, and an electrolyte was injected to produce the secondary battery of Example 1. As the electrolyte, an organic solvent was used, which consisted of ethylene carbonate (EC) and ethyl methyl carbonate (EMC) mixed in a volume ratio of 30:70, to which LiPF6 was added as a lithium salt at a concentration of 1.0 mol / L.

[0162] 2. Manufacturing of battery systems We manufactured a battery system including the aforementioned secondary battery and battery management device.

[0163] The battery management device includes the diagnostic unit and control unit mentioned above.

[0164] (1) Setting the first drive mode V 1a 2.8V, V 1b The voltage was set to 4.2V, and the secondary battery was configured to charge and discharge at a rate of 2.8V to 4.2V for at least one cycle.

[0165] (2) Setting of the second drive mode V 2a 2.5V, V 2b The voltage was set to 4.2V, and the secondary battery was configured to charge and discharge at a rate of 2.5V to 4.2V for at least one cycle.

[0166] (3) In the battery management device, the diagnostic unit diagnoses the normal operation status and abnormal operation status of the battery system. When the diagnostic unit diagnoses the normal operation status, the control unit controls the battery system in the first drive mode, and when the diagnostic unit diagnoses the abnormal operation status, the control unit controls the battery system in the second drive mode.

[0167] Example 2 1. Manufacturing of rechargeable batteries A secondary battery was manufactured in the same manner as in Example 1, except that the silicon-based active material and the carbon-based active material were mixed in a weight ratio of 12:88 to produce the negative electrode active material.

[0168] 2. Manufacturing of battery systems The battery system was manufactured in the same manner as in Example 1, except that the aforementioned secondary battery was used.

[0169] Comparative Example 1 1. Manufacturing of rechargeable batteries A secondary battery was manufactured using the same method as in Example 1.

[0170] 2. Manufacturing of battery systems The battery system was manufactured in the same manner as in Example 1, except that the first and second drive modes were set as described below.

[0171] (1) Setting the first drive mode V 1a 2.8V, V 1b The voltage was set to 4.2V, and the secondary battery was configured to charge and discharge at a rate of 2.8V to 4.2V for at least one cycle.

[0172] (2) Setting of the second drive mode V 2a 2.8V, V 2b The voltage was set to 4.2V, and the secondary battery was configured to charge and discharge at a rate of 2.8V to 4.2V for at least one cycle.

[0173] Comparative Example 2 1. Manufacturing of rechargeable batteries A secondary battery was manufactured using the same method as in Example 2.

[0174] 2. Manufacturing of battery systems The battery system was manufactured in the same manner as in Example 1, except that the first and second drive modes were set as described below.

[0175] (1) Setting the first drive mode V 1a 2.8V, V 1b The voltage was set to 4.2V, and the secondary battery was configured to charge and discharge at a rate of 2.8V to 4.2V for at least one cycle.

[0176] (2) Setting of the second drive mode V 2a 2.8V, V 2b The voltage was set to 4.2V, and the secondary battery was configured to charge and discharge at a rate of 2.8V to 4.2V for at least one cycle.

[0177] Comparative Example 3 1. Manufacturing of rechargeable batteries (1) Manufacturing of the positive electrode The positive electrode was manufactured using the same method as in Example 1.

[0178] (2) Manufacturing of the negative electrode The negative electrode was manufactured in the same manner as in Example 1, except that only a carbon-based active material was used as the negative electrode active material, and no silicon-based active material was used.

[0179] A secondary battery was manufactured in the same manner as in Example 1, except that the aforementioned positive electrode and negative electrode were used.

[0180] 2. Manufacturing of battery systems The battery system was manufactured in the same manner as in Example 1, except that the aforementioned secondary battery was used. That is, in Comparative Example 3 and Example 1, the first drive mode and the second drive mode were set in the same way.

[0181] Comparative Example 4 The battery system was manufactured in the same manner as in Comparative Example 3, except that the first and second drive modes were set as described below.

[0182] (1) Setting the first drive mode V 1a 2.8V, V 1b The voltage was set to 4.2V, and the secondary battery was configured to charge and discharge at a rate of 2.8V to 4.2V for at least one cycle.

[0183] (2) Setting of the second drive mode V 2a 2.8V, V 2b The voltage was set to 4.2V, and the secondary battery was configured to charge and discharge at a rate of 2.8V to 4.2V for at least one cycle.

[0184] [Table 1]

[0185] <Example of experiment> <Experimental Example 1: Evaluation of Energy Density> The battery systems manufactured in the above examples and comparative examples were charged and discharged at 25°C and 0.33C within a voltage range of 2.8V to 4.2V, and their energy density was measured. In this case, the energy density was calculated by multiplying the discharge capacity by the average voltage and then dividing by the unit weight of the lithium secondary battery, and the average voltage was the value obtained by dividing the integral value of the capacity-voltage profile curve by the capacity.

[0186] The results are shown in Table 2 below.

[0187] <Experimental Example 2:> After fully charging the battery systems manufactured in the above examples and comparative examples, discharge them until the State of Charge (SOC) of the negative electrode reaches 20%, discharge them at a constant power (CP) of 1100W at 45°C, and set the V value set in the examples and comparative examples. 2a The time it took to reach that point (output time) was measured.

[0188] [Table 2]

[0189] Referring to Table 2, it can be seen that the battery systems of Examples 1 and 2 not only have a higher energy density compared to Comparative Examples 1 to 4, but also show a significant increase in the time during which they exert output in the second drive mode.

[0190] Specifically, when comparing the battery systems of Example 1 and Comparative Example 1 with those of Example 2 and Comparative Example 2, it can be confirmed that the battery system according to the present invention shows a significant improvement in the effect of improving output time by adjusting the lower limit of the drive voltage in the second drive mode.

[0191] On the other hand, referring to the experimental results of the battery systems in Comparative Examples 3 and 4, it is clear that because silicon-based active materials were not used, not only was the energy density low, but the effect of increasing the output time by adjusting the lower limit of the drive voltage in the second drive mode was not particularly observed. Furthermore, it is clear that the battery systems of Comparative Examples 3 and 4 had lower output times compared to Examples 1 and 2, making them less suitable for dealing with emergency situations involving means of transportation.

Claims

1. A battery system for a means of transport, The battery system includes a secondary battery and a battery management device. The aforementioned secondary battery includes a positive electrode containing a positive electrode active material, a negative electrode containing a negative electrode active material, a separator, and an electrolyte. The negative electrode active material includes a silicon-based active material and a carbon-based active material. The battery management device includes a diagnostic unit and a control unit, The diagnostic unit diagnoses whether the means of transport is operating normally or abnormally. The control unit controls the battery system to charge and discharge the secondary battery in a first drive mode when the diagnostic unit is diagnosing the normal operation status, and to charge and discharge the secondary battery in a second drive mode when the diagnostic unit is diagnosing the abnormal operation status. In the first drive mode, the secondary battery is set to a first drive voltage range V １ａ ~V １ｂ The battery system is controlled to charge and discharge for more than one cycle. In the first drive voltage range, the upper limit V １ｂ This value was determined from 4.1V to 4.6V, with the lower limit V １ａ is 2.8V or higher １ｂ It is a value determined from among those less than or equal to, In the second drive mode, the secondary battery is set to the second drive voltage range V ２ａ ~V ２ｂ The battery system is controlled to charge and discharge for more than one cycle. In the second drive voltage range, the upper limit V ２ｂ is a value determined from 4.1 V to 4.6 V, and the lower limit V ２ａ is a value determined from less than 2.8 V, a battery system for moving means.

2. The aforementioned silicon-based active material is silicon (Si), silicon oxide (SiO ｘ The battery system for a means of transport according to claim 1, comprising at least one silicon-based core particle selected from the group consisting of , 0 < x < 2), silicon-carbon composites, and silicon-metal alloys.

3. The battery system for a means of transport according to claim 2, wherein the silicon-based core particles are made of a silicon-carbon composite.

4. The battery system for a means of transport according to claim 2, further comprising a carbon coating layer located on the silicon-based core particles.

5. The battery system for a means of transport according to claim 1, wherein the carbon-based active material comprises at least one selected from the group consisting of graphite, hard carbon, soft carbon, carbon black, graphene, and fibrous carbon.

6. The battery system for a means of transport according to claim 1, wherein the weight ratio of the silicon-based active material and the carbon-based active material is 1:99 to 40:

60.

7. The battery system for a means of transport according to claim 1, wherein the positive electrode active material comprises a lithium nickel oxide.

8. The battery system for a means of transport according to claim 7, wherein the lithium nickel oxide is a compound represented by the following chemical formula 1. [Chemical formula 1] Li ａ１ Ni ｂ１ Co ｃ１ M １ ｄ１ M ２ ｅ１ O ２ (In the above chemical formula 1, M １ M is Mn, Al, or a combination thereof. ２ (where a1, b1, c1, d1, and e1 are one or more elements selected from the group consisting of Zr, W, Y, Ba, Ca, Ti, Mg, Ta, and Nb, and a1, b1, c1, d1, and e1 are the atomic fractions of independent elements, such that 0.8 ≤ a1 ≤ 1.3, 0.8 ≤ b1 < 1, 0 < c1 < 0.2, 0 < d1 < 0.2, 0 ≤ e1 ≤ 0.1, and b1 + c1 + d1 + e1 = 1.)

9. The battery system for a means of transport according to claim 7, wherein the lithium nickel oxide is in the form of at least one single particle consisting of one nodule and a pseudo-single particle which is a composite of 30 or fewer nodules.

10. The aforementioned V １ａ The battery system for a means of transport according to claim 1, wherein the voltage is set to a value between 2.8V and 3.0V.

11. The aforementioned V ２ａ The battery system for a means of transport according to claim 1, wherein the voltage is set to a value between 2.4V and 2.7V.

12. The aforementioned V １ａ V ２ａ The battery system for a means of transport according to claim 1, wherein the ratio is 0.9 or less.

13. A method for controlling a battery system for a means of transport, The steps include providing a battery system that includes a secondary battery and a battery management device including a diagnostic unit and a control unit, The diagnostic unit diagnoses whether the means of transport is operating normally or abnormally, The steps include: when the diagnostic unit diagnoses the normal operation status, the control unit charges and discharges the secondary battery in a first drive mode; and when the diagnostic unit diagnoses the abnormal operation status, the control unit charges and discharges the secondary battery in a second drive mode. The aforementioned secondary battery includes a positive electrode containing a positive electrode active material, a negative electrode containing a negative electrode active material, a separator, and an electrolyte. The negative electrode active material includes a silicon-based active material and a carbon-based active material. In the first drive mode, the secondary battery is set to a first drive voltage range V １ａ ~V １ｂ The battery system is controlled to charge and discharge for more than one cycle. In the first drive voltage range, the upper limit V １ｂ This value was determined from 4.1V to 4.6V, with the lower limit V １ａ is 2.8V or higher １ｂ It is a value determined from among those less than or equal to, In the second drive mode, the secondary battery is set to the second drive voltage range V ２ａ ~V ２ｂ The battery system is controlled to charge and discharge for more than one cycle. In the second drive voltage range, the upper limit V ２ｂ This value was determined from 4.1V to 4.6V, with the lower limit V ２ａ A control method for a battery system for a means of transport, wherein the voltage is a value determined from among those less than 2.8V.

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