Battery pack, battery management system, and battery control method

Abstract

The present invention relates to a battery pack, a battery management system, and a battery control method and, more specifically, to a battery pack comprising: a battery module including a stack cell including a plurality of first battery cells arranged along a first direction and at least one second battery cell overlapping the stack cell in the first direction; a charging element for charging the second battery cell; a discharge element for discharging the second battery cell; a pressure sensor for measuring the internal pressure of the battery module; and a control element for controlling charging and discharging of the second battery cell according to the internal pressure measured by the pressure sensor.

Description

Battery pack, battery management system and battery control method

[0001] The present invention relates to a battery pack, a battery management system, and a battery control method.

[0002]

[0003] Typically, secondary batteries, unlike primary batteries, which are non-rechargeable, are rechargeable and dischargeable. They are used as an energy source in mobile devices, electric vehicles, hybrid vehicles, electric bicycles, uninterruptible power supplies (UPS), and other devices. Depending on the type of external device they are used in, they can be used as single batteries or as modules, multiple batteries connected together to form a single unit.

[0004] Small mobile devices such as cell phones can operate for a certain period of time with the output and capacity of a single battery, but in cases where long-term operation and high-power operation are required, such as electric vehicles and hybrid vehicles that consume a lot of power, a module form that includes multiple batteries is preferred due to issues with output and capacity, and the output voltage or output current can be increased depending on the number of built-in batteries.

[0005] Meanwhile, there is a need to provide a battery module or battery system capable of actively controlling the pressure applied to the cells of the battery module.

[0006] The above-described information disclosed in the background technology of this invention is only intended to improve understanding of the background of the present invention, and therefore may include information that does not constitute prior art.

[0007]

[0008] The problem to be solved by the present invention is to provide a battery pack capable of actively controlling the pressure applied to cells of a battery module.

[0009] Another problem to be solved by the present invention is to provide a battery management system and a battery control method capable of actively controlling the pressure applied to cells of a battery module.

[0010]

[0011] According to the concept of the present invention, a battery pack may include a battery module including a stack cell including a plurality of first battery cells arranged along a first direction and at least one second battery cell overlapping the stack cell in the first direction; a charging element for charging the second battery cell; a discharging element for discharging the second battery cell; a pressure sensor for measuring an internal pressure of the battery module; and a control element for controlling charging and discharging of the second battery cell according to the internal pressure measured by the pressure sensor.

[0012] According to another concept of the present invention, a battery management system may include a battery module unit including a stack cell including a plurality of first battery cells arranged along a first direction and at least one second battery cell overlapping the stack cell in the first direction; a pressure control unit including a charge / discharge control means for the second battery cell and an internal pressure measuring means for the battery module unit; and a control unit for controlling charge and discharge of the second battery cell according to the internal pressure of the battery module unit measured by the pressure measuring means.

[0013] According to another concept of the present invention, a battery control method may include a battery including the battery management system described above. The battery control method may include: inputting a first pressure and a second pressure higher than the first pressure to a control unit; measuring an internal pressure of the battery module unit using the pressure measuring means; charging the second battery cell if the measured internal pressure is lower than the first pressure; and discharging the second battery cell if the measured internal pressure is higher than the second pressure.

[0014]

[0015] The battery pack according to the present invention can actively control the pressure applied to the cells of the battery module, thereby optimizing the interfacial resistance between the electrode and the electrolyte, thereby improving the energy density of the secondary battery, improving the ion conductivity within the electrolyte, improving the charge / discharge speed of the secondary battery, and reducing the heat generation of the battery through a reduction in internal resistance, thereby ensuring stability, thereby extending the life of the secondary battery.

[0016]

[0017] FIG. 1 is a perspective view illustrating a battery pack according to one embodiment of the present invention.

[0018] FIGS. 2 and 3 are perspective views illustrating battery packs according to other embodiments of the present invention.

[0019] FIG. 4 is a perspective view illustrating a battery cell according to one embodiment of the present invention.

[0020] Figure 5 is a schematic diagram illustrating a battery cell according to one embodiment of the present invention.

[0021] Figure 6 is a schematic diagram illustrating a battery cell according to another embodiment of the present invention.

[0022] Figure 7 is a schematic diagram illustrating a battery cell according to another embodiment of the present invention.

[0023] FIG. 8 is a conceptual diagram illustrating a battery management system according to one embodiment of the present invention.

[0024] FIG. 9 is a flowchart for explaining a battery control method according to one embodiment of the present invention.

[0025]

[0026] To fully understand the structure and effects of the present invention, preferred embodiments of the present invention will be described with reference to the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but can be implemented in various forms and subject to various modifications. However, the description of these embodiments is provided solely to ensure a complete disclosure of the present invention and to fully inform those skilled in the art of the invention of the scope of the invention.

[0027] In this specification, when a component is referred to as being on another component, it means that it can be formed directly on the other component, or a third component may be interposed between them. Furthermore, in the drawings, the thicknesses of the components are exaggerated for the sake of clarity. Parts designated by the same reference numerals throughout the specification represent the same components.

[0028] Unless otherwise specified herein, the singular may also include the plural. Furthermore, unless otherwise specified, "A or B" may mean "including A, including B, or including A and B." As used herein, "comprises" and / or "comprising" do not exclude the presence or addition of one or more other components.

[0029] As used herein, “combination thereof” may mean mixtures, laminates, composites, copolymers, alloys, blends, and reaction products of the components.

[0030] Electronic or electrical devices and / or other related devices or components according to embodiments of the present invention may be implemented using any suitable hardware, firmware (e.g., application-specific integrated circuits), software, or a combination thereof. For example, various components of these devices may be formed on a single integrated circuit (IC) chip or on separate integrated circuit chips. Furthermore, various components of these devices may be provided on a flexible printed circuit film, a tape carrier package (TCP), a printed circuit board, or formed on a single substrate. Furthermore, various components of these devices may be processes or threads that perform one or more processors in one or more computing devices, execute computer program instructions, and interact with other system components to perform the various functions described above. Computer program instructions are stored in a memory that may be implemented in the computing device using a standard memory device, such as a random access memory (RAM). Furthermore, the computer program instructions may be stored on other non-transitory computer-readable media, such as a CD-ROM, a flash drive, etc. Additionally, those skilled in the art should recognize that the functions of various computing devices may be combined or integrated into a single computing device, or that the functions of a particular computing device may be distributed across one or more computing devices, without departing from the scope of the present invention.

[0031]

[0032] Referring to FIGS. 1 to 3, a battery pack of the present invention may include a stack cell (STK) including a plurality of first battery cells (CEL1) arranged along a first direction (Z1), a battery module (MOD) including at least one second battery cell (CEL2) overlapping the stack cell (STK) in the first direction (Z1), a charging element (CHA) for charging the second battery cell (CEL2), a discharging element (DIS) for discharging the second battery cell (CEL2), a pressure sensor (FSR) for measuring an internal pressure of the battery module (MOD), and a control element (CON) for controlling charging and discharging of the second battery cell (CEL2) according to the internal pressure measured by the pressure sensor (FSR).

[0033] Referring to FIGS. 1 to 3, a battery module (MOD) may include a stack cell (STK), a second battery cell (CEL2), and a plate assembly (PAS).

[0034] Meanwhile, the battery array including the stack cell (STK) and the second battery cell (CEL2) may be structurally coupled to form a single module by a coupling structure. In one embodiment of the present invention, the coupling structure may include a plate assembly (PAS) surrounding a side surface of the battery array including the stack cell (STK) and the second battery cell (CEL2). The plate assembly (PAS) may include an end plate (EPL) disposed at one end of the battery array and a pair of side plates (not shown) extending across both side surfaces of the battery array. Referring to FIG. 2, in one embodiment of the present invention, the end plate (EPL) may include a first end plate (EPL1) disposed at one end of the battery array and a second end plate (EPL2) disposed opposite to the first end plate (EPL1) in a first direction (Z1).

[0035] By the above-described bonding structure, the stack cell (STK) and the second battery cell (CEL2) are arranged at one or both ends of the battery array and are restrained by a fixed end plate (EPL). As a result, the end plate (EPL) can provide pressure acting along the first direction (Z1) due to a change in the volume of the second battery cell (CEL2), which will be described later.

[0036] The stack cell (STK) may include a plurality of first battery cells (CEL1) arranged along a first direction (Z1). Meanwhile, the plurality of first battery cells (CEL1) may be electrically connected to each other. The first battery cells (CEL1) may be electrically connected to each other through a bus bar (BB) that electrically connects electrode terminals (ELT) to each other.

[0037] The above stack cell (STK) may be configured to supply power to the outside. That is, the above stack cell (STK) may correspond to a practical energy storage component in the battery pack (PAK) of the present invention that stores energy by charging and is used as an energy source for mobile devices, electric vehicles, hybrid vehicles, electric bicycles, uninterruptible power supplies, etc. by discharging.

[0038] Meanwhile, the stack cell (STK) may be electrically connected to the second battery cell (CEL2). The second battery cells (CEL2) may be electrically connected to each other through a bus bar (BB) that electrically connects the electrode terminals (ELT) to each other. In one embodiment of the present invention, the stack cell (STK) may not be electrically connected to the second battery cell (CEL2).

[0039] The second battery cell (CEL2) may be configured to increase its volume by charging, thereby increasing the internal pressure of the battery module (MOD). The second battery cell (CEL2) may be configured to decrease its volume by discharging, thereby reducing the internal pressure of the battery module (MOD). That is, the end plate (EPL) described above may limit the space of the battery array including the stack cell (STK) and the second battery cell (CEL2), and within the limited space, the second battery cell (CEL2) may be configured to repeat volume changes by charging and discharging, thereby increasing or decreasing the pressure of the battery module (MOD) as needed.

[0040] Referring to FIG. 2, in one embodiment of the present invention, at least one of the second battery cells (CEL2) may be disposed adjacent to one surface of the stack cell (STK). The one of the second battery cells (CEL2) may be interposed between the first end plate (EPL1) and the one surface of the stack cell (STK). The other of the at least one second battery cell (CEL2) may be disposed adjacent to the other surface of the stack cell. The other of the second battery cells (CEL2) may be interposed between the second end plate (EPL2) and the other surface of the stack cell (STK).

[0041] In one embodiment of the present invention, the pair of second battery cells (CEL2) described above may be arranged adjacent to each other on both sides of the stack cell (STK). One side of each of the second battery cells (CEL2) may be in contact with an end plate (EPL1 or EPL2) having a fixed position, and the other side of each of the second battery cells (CEL2) may be in contact with the stack cell (STK). As a result, a pressure change due to a change in the volume of the second battery cell (CEL2) may be appropriately provided to the stack cell (STK).

[0042] Referring to FIG. 3, in one embodiment of the present invention, at least one of the second battery cells (CEL2) may be positioned between the plurality of first battery cells (CEL1). In this case, a pressure change due to a change in the volume of the second battery cell (CEL2) may be provided not only to both sides of the plurality of first battery cells (CEL1) but also to the central portion.

[0043] Meanwhile, even when at least one of the second battery cells is disposed between the plurality of first battery cells (CEL1), the first battery cell (CEL1) may be electrically connected to the second battery cell (CEL2). The second battery cells (CEL2) may be electrically connected to each other through a bus bar (BB) that electrically connects the electrode terminals (ELT) to each other. Meanwhile, although not shown, in one embodiment of the present invention, the first battery cell (CEL1) may not be electrically connected to the second battery cell (CEL2).

[0044] Referring to FIGS. 1 to 3, a battery pack (PAK) according to the present invention may include a pressure sensor (FSR) that measures the internal pressure of the battery module (MOD). The pressure sensor (FSR) may be placed on the second battery cell (CEL2). The pressure sensor (FSR, Force Sensitive Resistor) may have a configuration of a typical FSR sensor that numerically monitors the swelling pressure of the battery array by utilizing the property that the resistance value changes depending on physical force, weight, etc., but is not limited thereto.

[0045] Referring to FIGS. 1 to 3, a pressure sensor (FSR) according to one embodiment of the present invention may be disposed between an end plate (EPL) and a second battery cell (CEL2). Specifically, the pressure sensor (FSR) may be disposed between the end plate (EPL) and a second battery cell (CEL2) disposed adjacent to one surface of the stack cell (STK).

[0046] Referring to FIG. 4, the battery cell (1000) applicable to the first battery cell (CEL1) and the second battery cell (CEL2) may include an electrode assembly and a case accommodating the electrode assembly. At this time, the battery cell (1000) or the case forming the outer shape of the battery cell (1000) may include a terminal surface (1000a) including an electrode terminal (13), a bottom surface (1000b) opposite to the terminal surface (1000a), a main surface (1000c) connecting the terminal surface (1000a) and the bottom surface (1000b) and having a relatively wide area, and a side surface (1000d) connecting the terminal surface (1000a) and the bottom surface (1000b) and having a relatively narrow area. In one embodiment of the present invention, the battery cell (1000) may be formed in an approximately rectangular parallelepiped shape including a pair of main surfaces (1000c) facing each other along a first direction (Z1), a pair of side surfaces (1000d) facing each other along a second direction (Z2), and a terminal surface (1000a) and a bottom surface (1000b) facing each other along a third direction (Z3).

[0047] An electrode terminal (13) may be formed on the terminal surface (1000a) of the battery cell (1000), and in one embodiment of the present invention, the electrode terminal (13) may include a pair of a first electrode terminal (11) and a second electrode terminal (12) having opposite polarities. However, in another embodiment of the present invention, the electrode terminal (13) may include only one electrode terminal, and in this case, a part of the case of the battery cell (1000) may function as another electrode terminal. The battery cells (1000) may be arranged along the first direction (Z1) such that the main surfaces (1000c) of neighboring battery cells (1000) face each other.

[0048] In one embodiment of the present invention, the second battery cell (CEL2) may be a battery cell (1000) having the same configuration as the first battery cell (CEL1).

[0049]

[0050] In another embodiment of the present invention, the second battery cell (CEL2) may be a battery cell (1000) having a different configuration from the first battery cell (CEL1). In this case, the stiffness of the second battery cell may be less than the stiffness of the first battery cell (CEL1). The stiffness of the cell may be confirmed by performing a stiffness test by sampling a portion of the battery cell and then applying an external force until the battery cell is destroyed, or may be confirmed by performing a non-destructive stiffness test using vibration, but is not limited to the method of the stiffness test.

[0051] Lithium secondary batteries can experience swelling when repeatedly charged and discharged. This can occur due to the accumulation of gases generated by the decomposition of the internal electrolyte as a side reaction of repeated charging and discharging. Alternatively, when a high-capacity but high-volume expansion rate negative active material is applied to the electrode, the volume of the battery cell changes with charging and discharging, which can also cause swelling. Typically, when swelling occurs in a battery cell, it puts pressure on the internal structure of the cell, which can lead to safety issues such as internal short circuits, electrical problems, and reduced cycle life due to physical damage. To improve this swelling, the case forming the exterior of the battery cell can be made of a material with high stiffness.

[0052] For example, the case forming the outer shape of the first battery cell (CEL1) may be made of, but is not necessarily limited to, aluminum, high-strength nylon, high-strength plastics, and stainless steel.

[0053] Meanwhile, the second battery cell (CEL2) may be configured to increase or decrease the pressure of the battery module (MOD) through volume changes due to charging and discharging as described above. Accordingly, the case forming the outer shape of the second battery cell (CEL2) may include a flexible, ductile material that has relatively low stiffness and can be flexibly deformed. For example, the case forming the outer shape of the second battery cell (CEL2) may be made of, but is not necessarily limited to, rubber, elastomer, foam materials, silicone, and polyurethane.

[0054] Meanwhile, the case forming the outer appearance of the second battery cell (CEL2) may be the same as or different from the first battery cell (CEL1). For example, the case forming the outer appearance of the second battery cell (CEL2) may be made of aluminum, high-strength nylon, high-strength plastic, and stainless steel.

[0055] The second battery cell (CEL2) may be configured to be separately charged from the stack cell (STK). The second battery cell (CEL2) may be configured to be separately discharged from the stack cell (STK). Through this, the second battery cell (CEL2) may operate independently regardless of the charge and discharge status of the stack cell (STK), thereby appropriately controlling the internal pressure of the battery module (MOD).

[0056] The second battery cell (CEL2) may be configured to charge the stack cell (STK) using the stored reserve power. As described above, the second battery cell (CEL2) may appropriately maintain the internal pressure of the battery module (MOD) through charging and discharging. Meanwhile, since the second battery cell (CEL2) itself corresponds to a battery cell (1000), it may become an energy source that stores reserve power on its own while the battery module (MOD) maintains an appropriate internal pressure. That is, it may be configured to charge the stack cell (STK) using the reserve power stored in the second battery cell (CEL2). In this case, it may have a relatively higher energy density than a conventional battery pack that includes a separate pressure control means inside the battery module (MOD).

[0057] FIG. 5 is a conceptual diagram briefly illustrating a battery cell (1000) according to one embodiment of the present invention.

[0058] Referring to FIG. 5, the battery cell (1000) may be a lithium secondary battery (1000a). The first battery cell (CEL1) may be applied with the lithium secondary battery (1000a). The second battery cell (CEL2) may be applied with the lithium secondary battery (1000a). The lithium secondary battery (1000a) may include a positive electrode (10), a negative electrode (20), a separator (30), and an electrolyte (ELL).

[0059] The positive electrode (10) and the negative electrode (20) may be spaced apart from each other with a separator (30) therebetween. The separator (30) may be placed between the positive electrode (10) and the negative electrode (20). The positive electrode (10), the negative electrode (20), and the separator (30) may be in contact with the electrolyte (ELL). The positive electrode (10), the negative electrode (20), and the separator (30) may be impregnated in the electrolyte (ELL).

[0060] The electrolyte (ELL) may be a medium for transferring lithium ions between the positive electrode (10) and the negative electrode (20). Within the electrolyte (ELL), the lithium ions may pass through the separator (30) and move toward the positive electrode (10) or the negative electrode (20).

[0061] FIG. 6 is a conceptual diagram briefly illustrating a battery cell (1000) according to another embodiment of the present invention.

[0062] Referring to FIG. 6, the battery cell (1000) may be an all-solid-state battery (1000b). The first battery cell (CEL1) may be applied with the all-solid-state battery (1000b). The second battery cell (CEL2) may be applied with the all-solid-state battery (1000b). The all-solid-state battery (1000b) may include a positive electrode layer (100), a negative electrode layer (200) facing the positive electrode layer, and a solid electrolyte layer (300) disposed between the positive electrode layer (100) and the negative electrode layer (200). The all-solid-state battery (1000b) may further include an additional functional layer, such as an adhesion enhancing layer, disposed between the positive electrode layer (100) and the solid electrolyte layer (300) or between the negative electrode layer (200) and the solid electrolyte layer (300).

[0063] The solid electrolyte layer (300) is disposed between the positive electrode layer (100) and the negative electrode layer (200) and includes a sulfide-based solid electrolyte with excellent lithium ion conductivity characteristics.

[0064] The positive electrode layer (100) of one embodiment includes a positive electrode current collector (110) and a positive electrode active material layer (120) disposed on the positive electrode current collector (110). The positive electrode active material layer (120) may include a positive electrode active material, a solid electrolyte, a conductive material, and a binder.

[0065] The cathode current collector (110) can provide a reference surface on which the cathode active material layer (120) is arranged. The cathode current collector (110) can include a plate or foil including, for example, indium (In), copper (Cu), magnesium (Mg), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), nickel (Ni), zinc (Zn), aluminum (Al), germanium (Ge), lithium (Li), or an alloy thereof.

[0066] Meanwhile, unlike that illustrated in FIG. 6, in one embodiment of the present invention, the positive electrode collector (110) may be omitted. Although not illustrated, a carbon layer having a thickness of 0.1 μm to 4 μm may be additionally disposed between the positive electrode collector (110) and the positive electrode active material layer (120) to increase the bonding strength between the positive electrode collector (110) and the positive electrode active material layer (120).

[0067] The solid electrolyte layer (300) of one embodiment may include a sulfide-based solid electrolyte. The sulfide-based solid electrolyte may be manufactured by treating starting materials such as Li2S and P2S5 by a melting rapid cooling method or a mechanical milling method. In addition, a heat treatment may be performed after the treatment. The solid electrolyte may be amorphous, crystalline, or a mixture thereof. In addition, the solid electrolyte may include, for example, at least sulfur (S), phosphorus (P), and lithium (Li) as constituent elements among the above-described sulfide-based solid electrolyte materials. For example, the solid electrolyte may be a material including Li2S-P2S5. When using a sulfide-based solid electrolyte material including Li2S-P2S5 to form the solid electrolyte, the mixing molar ratio of Li2S and P2S5 is, for example, in the range of Li2S:P2S5=50:50 to 90:10.

[0068] Sulfide-based solid electrolytes include, for example, Li 7-x PS 6-x Cl x (0≤x≤2), Li 7-x PS 6-x Br x (0≤x≤2), and Li 7-x PS 6-x I xIt may be an argyrodite-type compound including at least one selected from (0≤x≤2). In particular, the sulfide-based solid electrolyte may be an argyrodite-type compound including at least one selected from Li6PS5Cl, Li6PS5Br, and Li6PS5I.

[0069] Alternatively, the sulfide-based solid electrolyte is Li 7-a M a PS 6-c X c It may be an argyrodite-type compound containing (0≤a≤2, (0≤c≤2)), where X may be F, Br, Cl, or a combination thereof. M is candium (Sc), yttrium (Y), titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), chromium (Cr), molybdenum (Mo), tungsten (W), manganese (Mn), technetium (Tc), rhenium (Re), iron (Fe), ruthenium (Ru), osmium (Os), cobalt (Co), rhodium (Rh), iridium (Ir), nickel (Ni), palladium (Pd), platinum (Pt), copper (Cu), silver (Ag), gold (Au), zinc (Zn), cadmium (Cd), mercury (Hg), aluminum (Al), gallium (Ga), indium (In), thallium (Tl), silicon (Si), germanium (Ge), tin (Sn), lead (Pb), arsenic (As), antimony (Sb), bismuth (Bi), or a combination thereof. Can be.

[0070] The density of the argyrodite-type solid electrolyte may be 1.5 g / cc to 2.0 g / cc. When the argyrodite-type solid electrolyte has a density of 1.5 g / cc or more, the internal resistance of the all-solid-state battery is reduced, and the defect of the solid electrolyte membrane being penetrated and short-circuited due to the formation of lithium dendrites can be prevented. The elastic modulus of the solid electrolyte is, for example, 15 GPa to 35 GPa.

[0071] The solid electrolyte layer (300) may further include a binder. The binder included in the solid electrolyte layer (300) may be, for example, styrene butadiene rubber (SBR), polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, etc., but is not limited thereto. The binder of the solid electrolyte layer (300) may be the same as or different from the binder included in the positive electrode active material layer (120) or the binder included in the negative electrode active material layer (220).

[0072] In one embodiment, the negative electrode layer (200) may include a negative electrode current collector (210) and a negative electrode coating layer (220) on the negative electrode current collector (210). The negative electrode current collector (210) may provide a reference surface on which the negative electrode coating layer (220) is disposed. The negative electrode current collector (210) may include, for example, a material that does not react with lithium, i.e., does not form both an alloy and a compound with lithium. For example, the negative electrode current collector (210) may include at least one metal selected from the group consisting of copper (Cu), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), and nickel (Ni). The thickness of the negative electrode current collector (210) may be 1 μm to 20 μm, more specifically 5 μm to 15 μm, and more specifically 7 μm to 10 μm.

[0073] The negative electrode current collector (210) may be composed of one of the above-described metals, or may include an alloy or coating material of two or more metals. The negative electrode current collector (210) may have, for example, a plate shape or a foil shape. Meanwhile, in one embodiment, the negative electrode current collector (210) may be omitted.

[0074] The negative electrode coating layer (220) can allow lithium metal to grow between the negative electrode current collector (210) and the all-solid-state battery (1000b) when charging. The negative electrode coating layer (220) can act as a protective layer for the lithium metal and simultaneously suppress the precipitation and growth of lithium dendrites.

[0075] The cathode coating layer (220) may include a metal and carbon. For example, the cathode coating layer (220) may include at least one metal selected from the group consisting of gold (Au), platinum (Pt), palladium (Pd), silicon (Si), silver (Ag), aluminum (Al), bismuth (Bi), tin (Sn), and zinc (Zn). The cathode coating layer (220) may include at least one carbon selected from the group consisting of carbon black, acetylene black, furnace black, ketjen black, and graphene. In one embodiment, the cathode coating layer (220) may include a mixture of carbon black and silver (Ag).

[0076] The cathode coating layer (220) may further include additives other than metal and carbon. The cathode coating layer (220) may further include, for example, at least one additive selected from the group consisting of a binder, a filler, a coating agent, a dispersant, and an ion conductive additive.

[0077] The negative electrode coating layer (220) may have a smaller thickness than the positive electrode active material layer (120). The thickness of the negative electrode coating layer (220) may be, for example, 50% or less, 40% or less, 30% or less, 20% or less, 10% or less, or 5% or less of the thickness of the positive electrode active material layer (120). The thickness of the negative electrode coating layer (220) may be, for example, 1 um to 20 um, 2 um to 10 um, or 3 um to 7 um. If the thickness of the negative electrode coating layer (220) is too thin, lithium dendrites formed between the negative electrode coating layer (220) and the negative electrode current collector (210) may cause the negative electrode coating layer (220) to collapse, thereby deteriorating the cycle characteristics of the first battery cell (CEL1). If the thickness of the cathode coating layer (220) increases excessively, the energy density of the all-solid-state battery (1000b) may decrease and the internal resistance of the all-solid-state battery (1000b) due to the cathode coating layer (220) may increase, thereby deteriorating the cycle characteristics of the first battery cell (CEL1).

[0078] Meanwhile, although not shown, a carbon layer may be further included to improve adhesion between the cathode coating layer (220) and the solid electrolyte layer (300).

[0079] FIG. 7 is a diagram illustrating a battery pack (PAK) including an all-solid-state battery (1000c) according to another embodiment of the present invention. The all-solid-state battery (1000c) may be applied to the first battery cell (CEL1). The all-solid-state battery (1000c) may be applied to the second battery cell (CEL2). Referring to FIG. 7, the negative electrode layer (200) of the all-solid-state battery (1000c) may further include a lithium metal layer (400) between the negative electrode current collector (210) and the negative electrode coating layer (220). The thickness of the lithium metal layer (400) may further increase when the all-solid-state battery (1000c) is charged. The thickness of the lithium metal layer (400) may further decrease when the all-solid-state battery (1000c) is discharged.

[0080] According to another embodiment of the present invention, a second battery cell (CEL2) may be applied to an all-solid-state battery (1000b) including the above-described negative electrode coating layer (220) or an all-solid-state battery (1000c) further including a lithium metal layer (400). In this case, the second battery cell (CEL2) may easily change its volume according to changes in thickness during charging and discharging, thereby changing the internal pressure of the battery module (MOD).

[0081] The cathode coating layer (220) serves as a protective layer for the lithium metal layer (400), and at the same time, can suppress the growth of lithium dendrites from the lithium metal layer (400).

[0082] The lithium metal layer (400) may be a metal thin film containing lithium or a lithium alloy. The lithium alloy may include, but is not limited to, a Li-Al alloy, a Li-Sn alloy, a Li-In alloy, a Li-Ag alloy, a Li-Au alloy, a Li-Zn alloy, a Li-Ge alloy, a Li-Si alloy, etc., and any lithium alloy may be used. The lithium metal layer (400) may contain one of these alloys or lithium. Alternatively, the lithium metal layer (400) may contain various types of alloys.

[0083] Meanwhile, the battery cell (1000) may experience volume changes due to various causes resulting from chemical and physical changes occurring within the battery. In particular, the aforementioned all-solid-state battery (1000b, 1000c) may experience changes in the thickness of the lithium metal layer (400) depending on charging and discharging, thereby causing volume changes between the charged and discharged states of the battery cell (1000).

[0084] According to one embodiment of the present invention, the volume change rate of the second battery cell (CEL2) may be greater than the volume change rate of the first battery cell (CEL1). The volume change rate may be expressed by the following mathematical expression 1.

[0085] [Mathematical Formula 1]

[0086] Volume change rate (%) = (1st direction thickness of battery cell in fully charged (100% SOC) state - 1st direction thickness of initial battery cell) / 1st direction thickness of initial battery cell X 100

[0087] However, the definition of the volume change rate is not necessarily limited to the above-described content, and the concept according to the present invention can be applied by defining the volume change rate in various ways. For example, in Mathematical Expression 1 below, the volume change rate is defined based on the thickness of the battery cell (1000) in the first direction (Z1), but the volume change rate can be defined by disassembling the electrode of a battery cell in a fully charged (100% SOC) state in a dry room, washing the disassembled negative electrode plate, and then using a micrometer to measure the difference between the thickness of the negative electrode and the thickness of the initial negative electrode. In addition, it goes without saying that any parameter that can represent the volume change according to the charging and discharging of the battery cell (1000) can be defined as the volume change rate.

[0088] Referring to FIG. 8, a battery pack (PAK) according to one embodiment of the present invention may include a charging element (CE) for charging a second battery cell (CEL2). A battery pack (PAK) according to one embodiment of the present invention may include a discharging element (DCE) for discharging the second battery cell (CEL2).

[0089] Each of the charging element (CE) and the discharging element (DIS) may include a field effect transistor (FET) and a parasitic diode (D). The connection direction between the source and the drain of the field effect transistor (FET) of the charging element (CE) may be set to be opposite to the direction of the field effect transistor (FET) of the discharging element (DCE). With this configuration, the field effect transistor (FET) of the charging element (CE) may be connected to limit the current flow from the external power source to the second battery cell (CEL2), while the field effect transistor (FET) of the discharging element (DCE) may be connected to limit the current flow from the second battery cell (CEL2) to the external resistor.

[0090] When the charging element (CE) is turned on, external power is supplied to the second battery cell (CEL2) to charge the second battery cell (CEL2), and when the discharging element (DCE) is turned on, an external resistor is supplied to the second battery cell (CEL2) to discharge the second battery cell (CEL2). Here, the field effect transistors (FETs) of the charging element (CE) and the discharging element (DCE) are switching elements, but are not limited thereto, and other types of electrical elements that perform switching functions may be used.

[0091] Referring to FIG. 8, a battery pack (PAK) according to one embodiment of the present invention may include a control element (COE) that controls charging and discharging of the second battery cell (CEL2) according to the internal pressure measured from the pressure sensor (FSR).

[0092] The above control element (COE) may be configured to control the switching elements of each of the charging element (CE) and the discharging element (DCE) to determine whether to turn them on. For example, if the internal pressure of the battery module (MOD) measured by the pressure sensor (FSR) is lower than a first pressure to be described later, the control element (COE) may be configured to turn on the charging element (CE) to charge the second battery cell (CEL2).

[0093] If the internal pressure of the battery module (MOD) measured from the pressure sensor (FSR) is higher than the second pressure to be described later, the discharge element (DCE) may be configured to turn on to discharge the second battery cell (CEL2).

[0094] The above control element (CDE) may be configured to maintain the remaining capacity (SoC, state of charge) of the second battery cell constant when the internal pressure of the battery module (MOD) measured from the pressure sensor (FSR) is between the first pressure and the second pressure to be described later.

[0095] A battery management system according to another embodiment of the present invention may include a battery module unit including a stack cell (STK) including a plurality of first battery cells (CEL1) arranged along a first direction (Z1) and at least one second battery cell (CEL2) overlapping the stack cell (STK) in the first direction (Z1), a pressure control unit including a charge / discharge control means for the second battery cell (CEL2) and an internal pressure measuring means for the battery module unit, and a control unit for controlling charge and discharge of the second battery cell (CEL2) according to the internal pressure of the battery module unit measured by the pressure measuring means.

[0096] The battery management system can monitor the voltage of the secondary cells (or battery modules) that make up the battery pack in real time through a cell balancing circuit, and if an overvoltage abnormality is detected through voltage monitoring, control the charge control switch or discharge control switch to stop charging and discharging of the battery pack.

[0097] If excessive swelling occurs in the battery cell (1000) and the internal pressure of the battery module (MOD) becomes excessively high, it may cause instability in the internal components of the battery cell (1000). To reduce deterioration, each battery cell (1000) included in the stack cell (STK) can apply mechanical pressure. This minimizes the interfacial resistance between the electrode plates and the electrolyte, thereby promoting the movement of ions within the electrolyte and preventing deterioration. An all-solid-state battery cell that uses a solid electrolyte as the electrolyte requires relatively high mechanical pressure for operation. Therefore, the battery module (MOD) needs to maintain an appropriate internal pressure.

[0098] The battery management system (2000) of the present invention can control the charging and discharging of the second battery cell (CEL2) according to the internal pressure of the battery module, thereby maintaining an appropriate internal pressure in the battery module.

[0099] Fig. 8 is a conceptual diagram for explaining a battery management system (2000) of the present invention. Referring to Fig. 8, the battery module unit (2100) may include a stack cell (STK) including a plurality of first battery cells (CEL1) arranged along a first direction (Z1) and at least one second battery cell (CEL2) overlapping the stack cell (STK) in the first direction (Z1). Although not illustrated in Fig. 8, the battery module unit (2100) may include the plate assembly (PAS) described above.

[0100] As for the first battery cell (CEL1), the stack cell (STK), the second battery cell (CEL2), and the plate assembly (PAS), substantially the same contents as described above may be applied, and thus, a detailed description thereof will be omitted below.

[0101] Referring to FIG. 8, the pressure control unit (2200) may include a charge / discharge control means of the second battery cell (CEL2) and an internal pressure measuring means of the battery module unit (2100).

[0102] The above-described charge / discharge control means may include a charging element (CE) and a discharging element (DCE). Since substantially the same content as described above may be applied to the charging element (CE) and the discharging element (DCE), a detailed description thereof will be omitted below. Furthermore, the above-described charge / discharge control means may further include any configuration for controlling the charging / discharging of the second battery cell (CEL2), in addition to the above-described charging element (CE) and discharging element (DCE).

[0103] The internal pressure measuring means may include a pressure sensor (FSR). Since the pressure sensor (FSR) is substantially the same as the above-described content, its description will be omitted below. Furthermore, the internal pressure measuring means may, of course, include any other configuration for measuring the internal pressure of the battery module unit (2100) in addition to the above-described pressure sensor (FSR).

[0104] Referring to Fig. 8, the control unit (2300) can control charging and discharging of the second battery cell (CEL2) according to the internal pressure of the battery module unit (2100) measured from the pressure measuring means. The control unit (2300) can include a control element (COE).

[0105] The control unit (2300) may further include an input means (not shown) capable of inputting a first pressure and a second pressure to maintain an appropriate internal pressure in the battery module unit. The first pressure may be lower than the second pressure. The control unit (2300) may further include a receiving means (not shown) for receiving a signal regarding the internal pressure of the battery module unit (2100) from the pressure sensor (FSR). The control unit (2300) may further include an output means (not shown) for outputting information regarding the internal pressure of the battery module unit (2100). Meanwhile, the control unit (2300) may further include any configuration for controlling charging and discharging of the second battery cell (CEL2).

[0106] According to one embodiment of the present invention, the battery management system (2000) may be configured such that the second battery cell (CEL2) is separately charged and discharged from the stack cell (STK). Accordingly, the second battery cell (CEL2) can operate independently, regardless of the charging and discharging state of the stack cell (STK), thereby appropriately controlling the internal pressure of the battery module unit (2100).

[0107] A battery management system (2000) according to one embodiment of the present invention may be configured to input a first pressure as a lower limit of the internal pressure of the battery module unit. The control unit (2300) may be configured to receive a signal regarding the internal pressure of the battery module unit (2100) and charge the second battery cell (CEL2) if the internal pressure of the battery module unit (2100) is lower than a preset first pressure. Through this, the battery module unit (2100) can appropriately maintain a pressure above a certain level. In this case, the battery cell (1000) can improve performance by optimizing the interfacial resistance between the electrode and the electrolyte.

[0108] A battery management system (2000) according to one embodiment of the present invention may be configured to input a second pressure as an upper limit of the internal pressure of the battery module unit (2100). The control unit (2300) may be configured to receive a signal regarding the internal pressure of the battery module unit (2100) and discharge the second battery cell (CEL2) if the internal pressure of the battery module unit (2100) is higher than a preset second pressure. Through this, the battery module unit (2100) can appropriately maintain a pressure below a certain level. In this case, the battery cell (1000) can prevent its internal configuration from being damaged by pressure above a certain level.

[0109] A battery management system (2000) according to one embodiment of the present invention may be configured to input a first pressure as a lower limit of the internal pressure of the battery module unit (2100) and a second pressure as an upper limit. The control unit (2300) receives a signal regarding the internal pressure of the battery module unit (2100) and, if the internal pressure of the battery module unit (2100) is between a preset first pressure and a preset second pressure, can maintain a constant state of charge (SoC) of the second battery cell (CEL2). Through this, the battery module unit (2100) can appropriately maintain a constant level of pressure. In this case, the battery cell (1000) can improve performance by optimizing the interfacial resistance between the electrode and the electrolyte, and can prevent the internal configuration from being damaged by a pressure exceeding a predetermined level.

[0110] A battery management system (2000) according to one embodiment of the present invention may be configured such that the stack cell (STK) supplies power externally. A detailed description thereof will be omitted below, as the above-described content is substantially applicable.

[0111] A battery management system (2000) according to one embodiment of the present invention may include a means for checking the remaining capacity (mAh) of the stack cell (STK). The control unit (2300) may be configured to receive a signal regarding the remaining capacity (mAh) of the stack cell (STK) and, when the remaining capacity falls below a certain level, charge the stack cell (STK) using the reserve power stored in the second battery cell (CEL2). Through this, the battery management system (2000) of the present invention can utilize the pressure control means as reserve power, thereby enabling flexible use of energy.

[0112] A battery control method according to one embodiment of the present invention may include the battery management system (2000) described above.

[0113] Referring to FIG. 9, a battery control method according to an embodiment of the present invention may include inputting a first pressure and a second pressure higher than the first pressure to the control unit (S100), measuring an internal pressure of the battery module unit using the pressure measuring means (S200), charging the second battery cell if the measured internal pressure is lower than the first pressure (S300, S400), and discharging the second battery cell if the measured internal pressure is higher than the second pressure (S500, S600).

[0114] A battery control method according to one embodiment of the present invention may further include maintaining the remaining capacity (SoC) of the second battery cell constant if the measured internal pressure is a value between the first pressure and the second pressure (S700).

[0115] While embodiments of the present invention have been described with reference to the attached drawings, the present invention may be implemented in other specific forms without altering the technical spirit or essential features thereof. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive.

Claims

1. A battery module comprising a stack cell including a plurality of first battery cells arranged along a first direction and at least one second battery cell overlapping the stack cell in the first direction; A charging element for charging the second battery cell; A discharge element for discharging the second battery cell; A pressure sensor for measuring the internal pressure of the battery module; and A battery pack comprising a control element that controls charging and discharging of the second battery cell according to the internal pressure measured from the pressure sensor.

2. In paragraph 1, The second battery cell is configured to increase its volume by the charging, thereby increasing the internal pressure of the battery module, A battery pack, wherein the second battery cell is configured to reduce its volume by the discharge, thereby reducing the internal pressure of the battery module.

3. In paragraph 1, A battery pack, wherein one of the at least one second battery cell is arranged adjacent to one side of the stack cell.

4. In paragraph 3, A battery pack, wherein another one of the at least one second battery cells is positioned adjacent to the other surface of the stack cell.

5. In paragraph 1, A battery pack, wherein at least one of the second battery cells is disposed between the plurality of first battery cells.

6. In paragraph 3, A battery pack, wherein the pressure sensor is disposed on the second battery cell.

7. In paragraph 1, A battery pack wherein the volume change rate of the second battery cell is greater than the volume change rate of the first battery cell.

8. In paragraph 1, The second battery cell includes a positive electrode layer, a negative electrode layer, and a solid electrolyte layer disposed between the positive electrode layer and the negative electrode layer, A battery pack, wherein the negative electrode layer includes a negative electrode current collector and a negative electrode coating layer on the negative electrode current collector.

9. In paragraph 8, The above cathode coating layer: At least one metal selected from the group consisting of gold (Au), platinum (Pt), palladium (Pd), silicon (Si), silver (Ag), aluminum (Al), bismuth (Bi), tin (Sn), and zinc (Zn); and A battery pack comprising at least one carbon selected from the group consisting of carbon black, acetylene black, furnace black, ketjen black, and graphene.

10. In paragraph 8, A battery pack, wherein the negative electrode layer further includes a lithium metal layer between the negative electrode current collector and the negative electrode coating layer.

11. In paragraph 1, The second battery cell includes a positive electrode, a negative electrode, and a separator disposed between the positive electrode and the negative electrode, A battery pack, wherein the positive electrode, the negative electrode, and the separator are impregnated in an electrolyte.

12. A battery module unit including a stack cell including a plurality of first battery cells arranged along a first direction and at least one second battery cell overlapping the stack cell in the first direction; A pressure control unit including a charge / discharge control means of the second battery cell and an internal pressure measuring means of the battery module unit; and A battery management system comprising a control unit that controls charging and discharging of the second battery cell according to the internal pressure of the battery module unit measured from the pressure measuring means.

13. In paragraph 12, A battery management system wherein the second battery cell is charged and discharged separately from the stack cell.

14. In paragraph 12, A battery management system in which the control unit receives a signal regarding the internal pressure and charges the second battery cell when the internal pressure of the battery module unit is lower than a preset first pressure.

15. In paragraph 12, A battery management system in which the control unit receives a signal regarding the internal pressure and discharges the second battery cell when the internal pressure of the battery module unit is higher than a preset second pressure.

16. In paragraph 12, A battery management system in which the control unit receives a signal regarding the internal pressure and maintains the remaining capacity (SoC, state of charge) of the second battery cell constant when the internal pressure of the battery module unit is between a preset first pressure and a preset second pressure.

17. In paragraph 12, The above stack cell is a battery management system that supplies power to the outside.

18. In paragraph 12, A battery management system that charges the stack cell using reserve power stored in the second battery cell.

19. In a battery including a battery management system according to Article 12, Inputting a first pressure and a second pressure higher than the first pressure into the control unit; Measuring the internal pressure of the battery module section using the pressure measuring means; Charging the second battery cell if the measured internal pressure is lower than the first pressure; and A battery control method comprising discharging the second battery cell if the measured internal pressure is higher than the second pressure.

Images