A low-temperature self-controlled self-heating all-solid-state battery

Abstract

This invention belongs to the field of solid-state battery technology, specifically relating to a low-temperature self-controlled self-heating all-solid-state battery, comprising a self-heating solid-state battery module and a normal solid-state battery module, wherein the self-heating solid-state battery module and the normal solid-state battery module are stacked and connected in series; multiple normal solid-state battery modules are stacked and connected in series with at least one self-heating solid-state battery module. This invention solves the problems of low heating rate and uneven heating by using an internal heating element, achieving uniform and rapid heating, thereby solving the problem of significant performance degradation of solid-state batteries in low-temperature environments, improving the capacity retention and stability of all-solid-state batteries in low-temperature environments, and improving the battery's usage characteristics.

Description

Technical Field

[0001] This invention belongs to the field of solid-state battery technology, specifically relating to a low-temperature self-controlled self-heating all-solid-state battery. Background Technology

[0002] Solid-state batteries, using solid electrolyte materials, possess inherent safety and are widely recognized as a promising future mainstream power battery technology. Unlike traditional lithium-ion batteries with fluid electrolytes, solid-state batteries can stack multiple battery cells consisting of a positive electrode, electrolyte, and negative electrode in series. Furthermore, they use metal bipolar plates instead of the positive and negative current collectors (with active materials of the same polarity on both sides) found in traditional liquid batteries; that is, the active materials on both sides of the bipolar plate have opposite polarities. Compared to the unipolar current collectors of traditional lithium-ion batteries, solid-state batteries using bipolar plates do not require the current from each plate to be drawn out and collected, thus achieving higher packing efficiency.

[0003] However, compared to the liquid electrolyte in traditional lithium-ion batteries, solid electrolytes exhibit reduced mass transfer capacity and lower electrode-electrolyte interface kinetics. Especially at low temperatures, their mass transfer and charge transfer resistance further increase, posing a significant challenge to charge and discharge performance. Therefore, improving the low-temperature performance of solid-state batteries is a critical problem that urgently needs to be solved. Existing technologies mainly fall into two categories: developing solid electrolytes and battery systems adapted to low-temperature conditions, and heating the battery. Developing new material systems is time-consuming and difficult to balance other performance aspects, such as oxidation stability and compatibility with the positive and negative electrodes. Battery heating methods can be categorized as external and internal based on the heating location: external heating utilizes air or liquid convection in a cooling system, but this method suffers from low heating rates (generally <1℃ / min) and uneven heating due to limitations in the heat source and the heat generation and conduction capabilities of the materials. Internal heating utilizes built-in metal foil to reduce heat loss and heat transfer paths, resulting in higher heating rates (up to 60℃ / min) and more uniform cell heating, making it a more promising heating solution.

[0004] However, internal heating places high demands on the fabrication and integration processes of the heating element, as well as the control of heating time and temperature. Currently, many publicly available technologies related to heating control exist, most of which use temperature sensors to monitor the battery surface temperature and control the on / off state of the heating circuit accordingly. However, temperature sensors are typically placed on the battery surface, making it impossible to accurately obtain internal cell temperature information for precise control. Furthermore, the heating control circuit increases the complexity of the battery management system's hardware and algorithms, and also has a certain impact on the battery system's energy density.

[0005] CN112786970A discloses an all-solid-state battery with self-heating function and its preparation method. First, an electrolyte slurry is coated onto a nickel mesh, dried to obtain a composite electrolyte layer, and then the positive electrode, negative electrode, and composite electrolyte layer are stacked and hot-pressed to form an all-solid-state battery. By directly heating the solid electrolyte using a nickel mesh, the heat transfer path can be shortened and the cell can be heated more uniformly. However, this technical solution requires high precision in controlling the heating time and temperature, but the solution does not clearly define the control method for the on / off state of the heating circuit; in addition, the nickel mesh in the solid electrolyte hinders ion transport, resulting in uneven current distribution; at the same time, the nickel mesh also increases the risk of short circuits at the positive and negative electrode contacts.

[0006] CN112838296A discloses a low-temperature lithium battery intelligent heating device and method based on shape memory effect. This technology eliminates the need for additional heating devices and temperature relay switches, controlling the on / off state of the self-heating circuit solely through a shape memory heating element and a switch. However, the switching method based on the shape memory metal element is a physical contact type, requiring a certain travel space for the metal element, which affects the battery's energy density. Furthermore, at the moment the switch contacts the heating element, the small and unstable contact area easily causes electrical sparks, potentially leading to internal battery safety hazards. Considering the complex mechanical environment of the battery system in actual automotive applications, intermittent contact and heating between the memory switch and the battery pack surface can easily occur, causing electrode attenuation and energy loss while further exacerbating safety risks. Summary of the Invention

[0007] In view of the shortcomings of existing methods, one of the objectives of this invention is to provide a solid-state battery with self-heating function, which improves the heating rate, reduces energy consumption and improves the uniformity of cell heating by using built-in heating elements, thereby efficiently and stably improving the low-temperature performance of solid-state batteries.

[0008] Furthermore, precise control of heating time and temperature is also crucial for effectively improving the low-temperature performance of batteries. Previous self-heating control strategies for batteries were mostly based on temperature sensors and control circuits. However, temperature sensors are typically difficult to embed inside the battery and obtain accurate temperature information; controlling the on / off state of circuit switches increases the complexity of electronic control and battery management algorithms. Therefore, a second objective of this invention is to construct a self-heating solid-state battery structure using positive temperature coefficient (PTC) and negative temperature coefficient (NTC) materials to create a self-controlled heating component that automatically activates at low temperatures and automatically stops at room temperature, thereby achieving simple and efficient heating control.

[0009] The specific technical solution is as follows:

[0010] This invention provides a low-temperature self-controlled self-heating all-solid-state battery that solves the problems of low heating rate and uneven heating by using a built-in heating element, achieving uniform and rapid heating. This solves the problem of significant performance reduction of solid-state batteries in low-temperature environments, improves the capacity retention and stability of all-solid-state batteries in low-temperature environments, and enhances the battery's usage characteristics.

[0011] A low-temperature self-controlled self-heating all-solid-state battery includes a self-heating solid-state battery module and a normal solid-state battery module, wherein the self-heating solid-state battery module and the normal solid-state battery module are stacked and connected in series.

[0012] Multiple normal solid-state battery modules are stacked and connected in series with at least one self-heating solid-state battery module.

[0013] A typical solid-state battery module includes a bipolar plate, a positive electrode active material layer, a solid electrolyte layer, and a negative electrode active material layer; the arrangement order of each layer includes:

[0014] Sequence A: Bipolar plate - Positive electrode active material - Solid electrolyte - Negative electrode active material;

[0015] Sequence B: Bipolar plate - Negative electrode active material - Solid electrolyte - Positive electrode active material;

[0016] Multiple normal solid-state battery modules stacked in series are in the same order.

[0017] The self-heating solid-state battery module comprises bipolar plates, a positive electrode active material layer, a solid electrolyte layer, a negative electrode active material layer, a PTC sheet, an NTC sheet, and a heating element. Bipolar plates are distributed on the upper and lower sides of the heating element. The other side of each of the two bipolar plates, together with the positive electrode active material layer, the solid electrolyte layer, and the negative electrode active material layer, forms a normal solid-state battery module. The arrangement order of the layers in the two normal solid-state battery modules is different. In each normal solid-state battery module, the active material not in contact with the bipolar plates of its own module contacts the two bipolar plates in contact with the heating element, thus forming a self-heating solid-state battery module. The outermost layers of the self-heating solid-state battery module are bipolar plates from two normal solid-state battery modules with different sequences. These are then stacked and connected in series with multiple other normal solid-state battery modules. When stacked and connected in series, the side of the self-heating solid-state battery module closest to the bipolar plate of sequence A is connected in series with the normal solid-state battery module of sequence A, and the side of the self-heating solid-state battery module closest to the bipolar plate of sequence B is connected in series with the normal solid-state battery module of sequence B.

[0018] There is a terminal at each end of the heating element and at each end of the two bipolar plates that contact the heating element; the terminals on the same side of the two bipolar plates are connected by NTC plates respectively; the terminal on one side of the heating element contacts the terminal on the same side of the bipolar plate above it through a PTC plate; the terminal on the other side of the heating element contacts the terminal on the same side of the bipolar plate below it through a PTC plate, thus forming a temperature control circuit and a heating circuit.

[0019] The bipolar plate material is Al, Cu, Ni, Ti or stainless steel SUS;

[0020] The material of the negative electrode active material layer is lithium, sodium, potassium, or an alloy composed of multiple metals from these metals.

[0021] The solid electrolyte layer is made of one or more combinations of perovskite, NASICON, LISICON, and garnet oxide solid electrolytes, or selected from glassy Li₂S-P₂S₅ and crystalline Li₂S₅. x M y PS z One or more of the following: glass-ceramic Li2S-P2S5 and Li6PSX5 sulfide solid electrolytes; or one or more combinations of PEO, PPC, PCL, PTMC, SN, PAN, MEEP polymer solid electrolytes; or one or more combinations of Li3MX6 halide solid electrolytes.

[0022] Li x M y PS z In the formula, M is one or more of Si, Ge, and Sn, x+4y+5=2z, 0≤y≤1;

[0023] In Li6PSX5, X = Cl, Br, I;

[0024] In Li3MX6, M is a transition metal element, and X = F, Cl, Br, I, a halogen element.

[0025] The positive electrode active material layer is composed of positive electrode active material powder, conductive agent, binder, and solid electrolyte particles. The positive electrode active material powder includes lithium cobalt oxide (LiCoO2), lithium manganese oxide (LiMnO2), and nickel-cobalt-manganese ternary lithium (LiNi). 1-x- y Co x Mn y O2, Lithium iron phosphate (LiFePO4), Lithium manganese iron phosphate (LiMnFe) 1-xOne or more of PO4 and sulfur-containing positive electrode active materials; conductive agents include one or more combinations of carbon black conductive agent (SP), graphite conductive agent, and graphene conductive agent; binders include one or more combinations of polyvinylidene fluoride (PVDF), polyacrylonitrile (PAN), polymethyl methacrylate (PMMA), and styrene-butadiene rubber (SBR). Among these, nickel-cobalt-manganese ternary lithium (LiNi) 1-x-y Co x Mn y O2, where 0≤x≤0.5 and 0≤y≤0.5.

[0026] The heating element is composed of a surface insulating material and an internal metal sheet. The insulating material completely encloses the metal sheet, with terminals extending only on both sides. The internal metal sheet is composed of a single metal or alloy of Ni, Pt, Cu, Fe, or Al.

[0027] The PTC sheet is made of a switchable positive temperature coefficient conductive composite material, which is composed of a polymer and conductive filler.

[0028] The NTC sheet is composed of two or more of the transition metal oxides V2O5, MnO2, Co2O3 or Al2O3 metal oxides using a ceramic sintering process, or is prepared by sol-gel method using V2O5 doped with Mo.

[0029] The self-heating all-solid-state battery provided by this invention has the following advantages: it solves the problems of low heating rate and uneven heating by using an internal heating element; it has a simple structure and can be well integrated with the solid-state battery production process; it is simple to manufacture and can be mass-produced; because the heating element is in full contact with the electrodes inside the battery, the contact area is large and the thermal conductivity is high, thus achieving efficient and uniform heating when releasing heat. It also solves the problem of significant performance degradation of solid-state batteries in low-temperature environments, improves the capacity retention and stability of all-solid-state batteries in low-temperature environments, and improves the battery's usage characteristics.

[0030] The self-controlled heating scheme based on self-heating all-solid-state batteries provided by this invention has the following advantages: by using PTC and NTC materials, it achieves self-controlled heating function with heating at low temperatures and stopping at room temperature, reducing the algorithm complexity of the battery management and thermal management systems; it reduces the number of electrical and mechanical components used, reducing the hardware complexity of the battery management and thermal management systems; the scheme has a simple structure and can be well integrated with the solid-state battery production process; the PTC and NTC sheets are small in size and have high space utilization, thus reducing the impact on the energy density of the battery system. Attached Figure Description

[0031] Figure 1 This invention relates to a low-temperature self-controlled self-heating all-solid-state battery structure;

[0032] Figure 2 This is a schematic diagram of the connection method of the low-temperature self-controlled self-heating structure of the present invention;

[0033] Figure 3 This is the equivalent circuit of the low-temperature self-controlled self-heating all-solid-state battery of the present invention. Detailed Implementation

[0034] This invention provides a low-temperature self-controlled self-heating all-solid-state battery. By using a built-in heating element 7, it solves the problems of low heating rate and uneven heating, and achieves uniform and rapid heating. This solves the problem of the significant performance reduction of solid-state batteries in low-temperature environments, improves the capacity retention and stability of all-solid-state batteries in low-temperature environments, and improves the battery's usage characteristics.

[0035] like Figure 1 As shown, a low-temperature self-controlled self-heating all-solid-state battery is composed of self-heating solid-state battery modules and normal solid-state battery modules stacked and connected in series. The number of each module can be selected according to the requirements, and the arrangement of the modules is not limited. It can be that every two normal solid-state battery modules are stacked and connected in series with one self-heating solid-state battery module, or every three normal solid-state battery modules are stacked and connected in series with at least one self-heating solid-state battery module.

[0036] A typical solid-state battery module consists of a bipolar plate 1, a positive electrode active material layer 2, a solid electrolyte layer 3, and a negative electrode active material layer 4. The arrangement of these layers can be either sequence A: bipolar plate 1 - positive electrode active material - solid electrolyte - negative electrode active material (if reversed, the effect of negative electrode active material - solid electrolyte - positive electrode active material - bipolar plate 1 is the same, and it is considered the same sequence); or sequence B: bipolar plate 1 - negative electrode active material - solid electrolyte - positive electrode active material (if reversed, the effect of positive electrode active material - solid electrolyte - negative electrode active material - bipolar plate 1 is the same, and it is considered the same sequence). When multiple typical solid-state battery modules are stacked in series, active materials of different polarities need to be distributed on the upper and lower sides of bipolar plate 1. That is, the polarity of the active material in the previous typical solid-state battery module that is not in contact with bipolar plate 1 is opposite to the polarity of the active material in the next typical solid-state battery module that is in contact with bipolar plate 1. In other words, multiple typical solid-state battery modules stacked in series follow the same sequence.

[0037] The self-heating solid-state battery module consists of a bipolar plate 1, a positive electrode active material layer 2, a solid electrolyte layer 3, a negative electrode active material layer 4, a PTC sheet 5, an NTC sheet 6, and a heating element 7. Bipolar plates 1 are distributed on the upper and lower sides of the heating element 7. The other side of each of the two bipolar plates 1 in contact with the heating element 7 forms a normal solid-state battery module, with the positive electrode active material layer 2, the solid electrolyte layer 3, and the negative electrode active material layer 4 respectively. The two normal solid-state battery modules are arranged in different orders. The active materials in the two normal solid-state battery modules that are not in contact with their own bipolar plates 1 contact the two bipolar plates 1 in contact with the heating element 7, thus forming the self-heating solid-state battery module. The outermost sides of the self-heating solid-state battery module are bipolar plates 1 from two normal solid-state battery modules with different orders. These can be stacked and connected in series with multiple other normal solid-state battery modules. When stacked and connected in series, the side of the self-heating solid-state battery module with bipolar plate 1 in order A can only connect to normal solid-state battery modules in order A, and the side of the self-heating solid-state battery module with bipolar plate 1 in order B can only connect to normal solid-state battery modules in order B. Thus, by connecting multiple normal solid-state battery modules in series, and connecting normal solid-state battery modules in series with self-heating solid-state battery modules, a fully solid-state battery with self-heating function is finally formed.

[0038] The present invention provides a low-temperature self-controlled self-heating all-solid-state battery, which also includes a self-heating solid-state battery that automatically adjusts the on / off state of the heating circuit according to the internal temperature of the battery without human intervention or circuit control. For example... Figure 1 As shown, in the self-heating solid-state battery module, each end of the heating element 7 and each end of the two bipolar plates 1 in contact with the heating element 7 has a terminal for forming a circuit connection with other components. The terminals on the same side of the two bipolar plates 1 are connected via NTC sheets 6. The terminal on one side of the heating element 7 contacts the right terminal of the bipolar plate 1 above it via a PTC sheet 5, and the terminal on the other side of the heating element 7 contacts the left terminal of the bipolar plate 1 below it via a PTC sheet 5, thereby forming a temperature control circuit and a heating circuit. The above connection method is not limited to welding or bonding, or the above NTC and PTC materials can be prepared by sputtering, coating, sintering, sol-gel method, etc. on a unified current collector. Figure 2 This is a schematic diagram of one type of adhesive bonding method.

[0039] To facilitate understanding its working principle, the equivalent circuit is as follows: Figure 3 As shown. The heating element 7 in the self-heating solid-state battery module is equivalent to... Figure 3In the circuit diagram, the two bipolar plates 1 in contact with the heating element 7 are equivalent to wires in the circuit. The PTC chip 5 and NTC chip 6 are equivalent to switches in the diagram. The PTC chip 5 has the following characteristics: when current is applied, as the internal temperature of the battery rises, the resistivity of the PTC chip 5 increases rapidly within a specific temperature range, causing its resistance to approach infinity and the current to approach infinitesimal, thus functioning as a switch to break the circuit. The NTC chip 6 has the following characteristics: when current is applied, due to its high initial resistivity, the resistance of the NTC chip 6 approaches infinity, and the current to approach infinitesimal, resulting in an open circuit. As the internal temperature of the battery rises, the resistivity of the NTC chip 6 decreases rapidly within a specific temperature range, causing its resistance to decrease and the current to increase, thus functioning as a circuit connection.

[0040] In practical applications, PTC chip 5 exhibits low resistivity at 0℃ and below, and its resistivity increases rapidly with increasing temperature within the range of 0℃ to 20℃. These characteristics result in PTC chip 5 having low resistance at low temperatures and a resistance approaching infinity at room temperature. NTC chip 6, on the other hand, has high resistivity at 0℃ and below, and its resistivity decreases rapidly with increasing temperature within the range of 0℃ to 20℃. These characteristics result in PTC chip 5 having extremely high resistance at low temperatures and a low resistance at room temperature. When the low-temperature self-regulating and self-heating all-solid-state battery is in a sub-zero environment, based on the aforementioned characteristics, the PTC chip 5 has a low resistance and forms a heating path when connected to the heating element 7. Meanwhile, the resistance of the NTC chip 6 tends to be infinite at low temperatures, and the current in the path formed when connected to the bipolar plate 1 is very small, essentially an open circuit. Therefore, in the built-in self-heating solid-state battery module within the low-temperature self-regulating and self-heating all-solid-state battery, the current flow is bipolar plate 1 - PTC chip 5 - heating element 7 - PTC chip 5 - bipolar plate 1. The current generates Joule heat after passing through the heating element 7, which heats the positive electrode inside the battery. The negative electrode and solid electrolyte are heated. As heat accumulates, the internal temperature of the battery rises to 20°C. According to the temperature characteristics of PTC plate 5 and NTC plate 6, the resistance of PTC plate 5 increases rapidly and tends to infinity. The circuit between the bipolar plate 1 connected to it and the heating element 7 is broken, and the heating element 7 no longer generates Joule heat. The resistance of NTC plate 6 decreases, and the two bipolar plates 1 connected to it are connected, forming a circuit. The current flows from bipolar plate 1 to NTC plate 6 to bipolar plate 1. At this time, the battery can work normally and has good performance.

[0041] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0042] Low-temperature self-controlled self-heating all-solid-state batteries, including normal solid-state battery modules and self-heating solid-state battery modules.

[0043] (1) Normal solid-state battery module

[0044] A normal solid-state battery module consists of a negative electrode active material layer 4, a solid electrolyte layer 3, a positive electrode active material layer 2, and a bipolar plate 1.

[0045] The material of the negative electrode active material layer 4 includes, but is not limited to, metals such as lithium, sodium, and potassium, or alloys composed of multiple of these metals.

[0046] The material of solid electrolyte layer 3 is perovskite type (such as Li). 0.33 La 0.56 TiO3, LLTO), NASICON type (such as Li) 1.3 Al 0.3 Ti 1.7 (PO4)3, LATP), LISICON (such as Li 10 GeP2S 12 LGPS type and garnet type (such as Li7La3Zr2O) 12 One or more combinations of LZO oxide solid electrolytes, or selected from glassy Li₂S-P₂S₅, crystalline Li₂O, and other solid electrolytes. x M y PS z (where M is one or more of Si, Ge, Sn, x+4y+5=2z, 0≤y≤1), one or more combinations of sulfide solid electrolytes of glass ceramic state Li2S-P2S5 and Li6PSX5 (X=Cl, Br, I), or one or more combinations of polymer solid electrolytes selected from PEO, PPC, PCL, PTMC, SN, PAN, MEEP, or one or more combinations of halide solid electrolytes selected from Li3MX6 (M is a transition metal element, X=F, Cl, Br, I halogen element).

[0047] The positive electrode active material layer 2 is composed of positive electrode active material powder, conductive agent, binder, and solid electrolyte particles. The positive electrode active material powder includes lithium cobalt oxide (LiCoO2), lithium manganese oxide (LiMnO2), and nickel-cobalt-manganese ternary lithium (LiNiO2). 1-x- y Co x Mn y O2, where 0≤x≤0.5 and 0≤y≤0.5), lithium iron phosphate (LiFePO4), lithium manganese iron phosphate (LiMnFe 1-x The active materials include one or more of PO4 and sulfur-containing positive electrode active materials; the conductive agents include one or more combinations of carbon black conductive agents (SP), graphite conductive agents and graphene conductive agents; the binders include one or more combinations of polyvinylidene fluoride (PVDF), polyacrylonitrile (PAN), polymethyl methacrylate (PMMA), and styrene-butadiene rubber (SBR).

[0048] The material of the bipolar plate 1 can be metal foil such as Al, Cu, Ni, Ti or stainless steel SUS.

[0049] (2) Self-heating solid-state battery module

[0050] The self-heating solid-state battery module consists of a bipolar plate 1, a positive electrode active material layer 2, a solid electrolyte layer 3, a negative electrode active material layer 4, a PTC sheet 5, an NTC sheet 6, and a heating element 7.

[0051] The material of the negative electrode active material layer 4 includes, but is not limited to, metals such as lithium, sodium, and potassium, or alloys composed of multiple of these metals.

[0052] The material of solid electrolyte layer 3 is perovskite type (such as Li). 0.33 La 0.56 TiO3, LLTO), NASICON type (such as Li) 1.3 Al 0.3 Ti 1.7 (PO4)3, LATP), LISICON (such as Li 10 GeP2S 12 LGPS type and garnet type (such as Li7La3Zr2O) 12 One or more combinations of LZO oxide solid electrolytes, or selected from glassy Li₂S-P₂S₅, crystalline Li₂O, and other solid electrolytes. x M y PS z (where M is one or more of Si, Ge, Sn, x+4y+5=2z, 0≤y≤1), one or more combinations of sulfide solid electrolytes of glass ceramic state Li2S-P2S5 and Li6PSX5 (X=Cl, Br, I), or one or more combinations of polymer solid electrolytes selected from PEO, PPC, PCL, PTMC, SN, PAN, MEEP, or one or more combinations of halide solid electrolytes selected from Li3MX6 (M is a transition metal element, X=F, Cl, Br, I halogen element).

[0053] The positive electrode active material layer 2 is composed of positive electrode active material powder, conductive agent, binder, and solid electrolyte particles. The positive electrode active material powder includes lithium cobalt oxide (LiCoO2), lithium manganese oxide (LiMnO2), and nickel-cobalt-manganese ternary lithium (LiNiO2). 1-x- y Co x Mn y O2, where 0≤x≤0.5 and 0≤y≤0.5), lithium iron phosphate (LiFePO4), lithium manganese iron phosphate (LiMnFe 1-xThe active materials include one or more of PO4 and sulfur-containing positive electrode active materials; the conductive agent includes one or more combinations of carbon black conductive agent (SP), graphite conductive agent and graphene conductive agent; the binder includes one or more combinations of polyvinylidene fluoride (PVDF), polyacrylonitrile (PAN), polymethyl methacrylate (PMMA) and styrene-butadiene rubber (SBR).

[0054] The material of the bipolar plate 1 can be metal foil such as Al, Cu, Ni, Ti or stainless steel SUS.

[0055] The heating element 7 consists of a surface insulating material and an internal metal sheet. The insulating material completely encloses the metal sheet, with terminals protruding only on both sides. The insulating material can be an organic insulating polymer such as polyimide (PI), polypropylene (PP), polyethylene (PE), or polyethylene terephthalate (PET). The internal metal sheet is made of single metals or alloys such as Ni, Pt, Cu, Fe, or Al.

[0056] PTC sheet 5 is made of a switch-type positive temperature coefficient conductive composite material, which is generally composed of a polymer and conductive fillers. The polymer uses polyolefins such as polyethylene, polyethylene oxide (PEO), polyvinyl chloride (PVC), and ethylene-vinyl acetate copolymer (EVA); the conductive fillers use conductive carbon black, graphite, graphene, and highly conductive metals such as nickel powder, copper powder, aluminum powder, and platinum powder.

[0057] NTC sheet 6 is composed of two or more of transition metal oxides such as V2O5, MnO2, Co2O3 or metal oxides such as Al2O3, using ceramic sintering process, or prepared by magnetron sputtering, or prepared by sol-gel method using V2O5 doped with Mo element.

[0058] The connection methods between NTC sheet 6 and PTC sheet 5 and the bipolar plate 1 and the terminals of heating element 7 are not limited to ultrasonic welding, laser welding, friction welding, or conductive gel bonding, and are not limited to organic polymers or organic-inorganic composite materials with electronic conductivity.

[0059] Example 1: Low-Temperature Self-Controlled Self-Heating All-Solid-State Battery

[0060] like Figure 1 and Figure 2As shown, the all-solid-state battery with self-heating function is composed of self-heating solid-state battery modules and normal solid-state battery modules stacked and connected in series. The number of each module can be selected according to the needs, and the arrangement of the modules is not limited. It can be that every two normal solid-state battery modules are stacked and connected in series with at least one self-heating solid-state battery module, or every three normal solid-state battery modules are stacked and connected in series with at least one self-heating solid-state battery module.

[0061] (1) Normal solid-state battery module

[0062] A typical solid-state battery module consists of a bipolar plate (1), a positive electrode active material layer (2), a solid electrolyte layer (3), and a negative electrode active material layer (4). The materials selected are as follows:

[0063] 1) Bipolar plate 1 is made of 20μm SUS 316L stainless steel;

[0064] 2) The thickness of the positive electrode active material layer 2 is 200 μm, and it consists of 95% NMC622 positive electrode active material, 1% polyvinylidene fluoride (PVDF), 2% carbon black conductive agent (SP), and 2% solid electrolyte particles by mass. NMC622 is a nickel-manganese-cobalt ternary material, and LiNi... 1-x-y Co x Mn y O2 (where 0≤x≤0.5, 0≤y≤0.5), when x=0.2y=0.2 is NMC622, the material of the solid electrolyte particles is lithium lanthanum zirconium oxide LLZO (Li7La3Zr2O) 12 );

[0065] 3) Solid electrolyte layer 3 is lithium lanthanum zirconium oxide LLZO (Li7La3Zr2O) 12 Garnet-type oxide solid electrolyte;

[0066] 4) The negative electrode active material layer 4 is a 300μm thick metallic lithium.

[0067] The arrangement order of each layer can be either sequence A: bipolar plate 1 - positive electrode active material - solid electrolyte - negative electrode active material (if reversed, the effect of negative electrode active material - solid electrolyte - positive electrode active material - bipolar plate 1 is the same as this sequence, and it is considered to be the same sequence), or sequence B: bipolar plate 1 - negative electrode active material - solid electrolyte - positive electrode active material (if reversed, the effect of positive electrode active material - solid electrolyte - negative electrode active material - bipolar plate 1 is the same as this sequence, and it is considered to be the same sequence). When multiple normal solid-state battery modules are stacked in series, active materials of different polarities need to be distributed on the upper and lower sides of bipolar plate 1. That is, the polarity of the active material in the previous normal solid-state battery module that is not in contact with bipolar plate 1 is opposite to the polarity of the active material in the next normal solid-state battery module that is in contact with bipolar plate 1. In other words, the multiple normal solid-state battery modules stacked in series are in the same sequence. In this embodiment, three modules of sequence A and three modules of sequence B are prepared respectively. Two sequential A modules are compacted and stacked in series, and two sequential B modules are compacted and stacked in series to obtain a normal solid-state battery module after stacking and series connection.

[0068] (2) Self-heating solid-state battery module

[0069] The self-heating solid-state battery module consists of a bipolar plate 1, a positive electrode active material layer 2, a solid electrolyte layer 3, a negative electrode active material layer 4, a PTC sheet 5, an NTC sheet 6, and a heating element 7. The material selection and manufacturing process are as follows:

[0070] 1) Bipolar plate 1 is made of 20μm SUS 316L stainless steel;

[0071] 2) The heating element 7 is composed of a surface insulating material and an internal metal sheet. The surface insulating material is polyethylene (PE), and the internal metal sheet is a nickel sheet. The nickel sheet has protruding terminals at both ends, and the insulating polyethylene material completely wraps the nickel sheet.

[0072] 3) The PTC sheet 5 is made of a switch-type positive temperature coefficient conductive composite material, which is generally composed of a polymer and a conductive filler. The polymer is polyethylene, and the conductive filler is nickel powder sintered to form a sheet-like conductive material.

[0073] 4) NTC sheet 6 is prepared by sol-gel method using V2O5 doped with Mo;

[0074] 5) The NTC, PTC and bipolar plate 1 are all connected by ultrasonic welding.

[0075] Each end of the heating element 7 and each end of the two bipolar plates 1 in contact with the heating element 7 has a terminal for forming a circuit connection with other components. The terminals on the same side of the two bipolar plates 1 are connected through NTC plates 6. The terminal on one side of the heating element 7 is connected to the right terminal of the bipolar plate 1 above it through a PTC plate 5. The terminal on the other side of the heating element 7 is connected to the left terminal of the bipolar plate 1 below it through a PTC plate 5, thereby forming a temperature control circuit and a heating circuit.

[0076] Bipolar plates 1 are distributed on the upper and lower sides of the heating element 7. Two normal solid-state battery modules as described above are distributed on the other side of each of the two bipolar plates 1 that are in contact with the heating element 7. The two normal solid-state battery modules are in different orders. The active materials in the two normal solid-state battery modules that are not in contact with the bipolar plates 1 of their respective modules are in contact with the other side of the two bipolar plates 1 that are in contact with the heating element 7, thereby forming a self-heating solid-state battery module. In this embodiment, one normal solid-state battery module of sequence A and one normal solid-state battery module of sequence B prepared in step (1) are taken. The normal solid-state battery module of sequence A is placed above the bipolar plate 1 that is in contact with the upper side of the heating element 7, so that the negative electrode active material layer 4 in the normal solid-state battery module of sequence A is close to the bipolar plate 1. The normal solid-state battery module of sequence B is placed below the bipolar plate 1 that is in contact with the lower side of the heating element 7, so that the positive electrode active material layer 2 in the normal solid-state battery module of sequence B is close to the bipolar plate 1. After compaction, a self-heating solid-state battery module is formed. The outermost layers of the self-heating solid-state battery module consist of bipolar plates 1 from two normal solid-state battery modules in different sequences. These can be stacked and connected in series with multiple other normal solid-state battery modules. During this stacking and series connection, the side of the self-heating solid-state battery module with bipolar plate 1 closest to sequence A can only connect with normal solid-state battery modules of sequence A, and the side with bipolar plate 1 closest to sequence B can only connect with normal solid-state battery modules of sequence B. Thus, through the series connection of multiple normal solid-state battery modules and the series connection of normal solid-state battery modules with the self-heating solid-state battery module, a fully solid-state battery with self-heating functionality is ultimately formed. In this embodiment, two sequential A modules and two sequential B modules prepared in step (1) are stacked and connected in series. The two sequential A modules are placed above the self-heating solid-state battery module, ensuring that the uppermost bipolar plate 1 of the self-heating solid-state battery module is in contact with the exposed negative electrode active material layer 4 of the two sequential A modules. The two sequential B modules are placed below the self-heating solid-state battery module, ensuring that the lowermost bipolar plate 1 of the self-heating solid-state battery module is in contact with the exposed positive electrode active material layer 2 of the two sequential B modules. After lamination and compaction, the series connection of the normal solid-state battery module and the self-heating solid-state battery module is completed, and finally a full solid-state battery with self-heating function is formed.

[0077] Example 2: Application of Low-Temperature Self-Controlled Self-Heating All-Solid-State Batteries

[0078] The low-temperature self-controlled self-heating all-solid-state battery prepared in Example 1 was placed in a battery environmental test chamber, and the ambient temperature was set to -20°C for a 0.2C low-rate charge-discharge experiment. Its equivalent circuit is as follows. Figure 3 As shown. A normal solid-state battery module is equivalent to a power source in a circuit, while the heating element 7 in a self-heating solid-state battery module is equivalent to... Figure 2 In the circuit diagram, the two bipolar plates 1 in contact with the heating element 7 are equivalent to wires in the circuit. The PTC chip 5 and NTC chip 6 are equivalent to switches in the diagram. The PTC chip 5 has the following characteristics: when current is applied, as the internal temperature of the battery rises, the resistivity of the PTC chip 5 increases rapidly within a specific temperature range, causing its resistance to approach infinity and the current to approach infinitesimal, thus functioning as a switch to break the circuit. The NTC chip 6 has the following characteristics: when current is applied, due to its high initial resistivity, the resistance of the NTC chip 6 approaches infinity, and the current to approach infinitesimal, resulting in an open circuit. As the internal temperature of the battery rises, the resistivity of the NTC chip 6 decreases rapidly within a specific temperature range, causing its resistance to decrease and the current to increase, thus functioning as a circuit connection. In this embodiment, the PTC chip 5 has a low resistivity at -20°C, acting as a conductive wire to connect the circuit, equivalent to a closed switch. The NTC chip 6 has a high resistivity at -20°C, acting as a circuit breaker, equivalent to an open switch. Thus, in the solid-state battery module with the built-in heating element 7 inside the self-controlled and self-heating solid-state battery, the current flow is bipolar plate 1 - PTC chip 5 - heating element 7 - PTC chip 5 - bipolar plate 1. After the current passes through the heating element 7, Joule heat is quickly generated, rapidly and evenly heating the positive and negative electrodes and the solid electrolyte inside the battery. Uniform heating; as heat accumulates, when the internal temperature of the battery rises to about 20℃, the resistivity of PTC piece 5 increases rapidly with temperature in the range of 0℃ to 20℃, and the resistance approaches infinity. The current passing through it approaches 0, which is equivalent to the switch being turned off. The resistivity of NTC piece 6 decreases rapidly with temperature in the range of 0℃ to 20℃, and the resistance decreases rapidly. The two bipolar plates 1 connected to it are turned on, which is equivalent to the switch being closed, forming a circuit. The current flows from bipolar plate 1 to NTC piece 6 to bipolar plate 1. At this time, the battery can work normally and has good performance.

Claims

1. A low-temperature self-controlled self-heating all-solid-state battery, characterized in that, It includes a self-heating solid-state battery module and a normal solid-state battery module, wherein the self-heating solid-state battery module and the normal solid-state battery module are stacked and connected in series. Multiple normal solid-state battery modules are stacked and connected in series with at least one self-heating solid-state battery module; The self-heating solid-state battery module comprises a bipolar plate (1), a positive electrode active material layer (2), a solid electrolyte layer (3), a negative electrode active material layer (4), a PTC sheet (5), an NTC sheet (6), and a heating element (7); the heating element (7) has bipolar plates (1) distributed on its upper and lower sides, and the other side of the two bipolar plates (1) together with the positive electrode active material layer (2), the solid electrolyte layer (3), and the negative electrode active material layer (4) form a normal solid-state battery module, and the arrangement order of each layer of the two normal solid-state battery modules is different; There is a terminal at each end of the heating element (7) and at each end of the two bipolar plates (1) that are in contact with the heating element (7); the terminals on the same side of the two bipolar plates (1) are connected by NTC plates (6), the terminal on one side of the heating element (7) is in contact with the terminal on the same side of the bipolar plate (1) above it through PTC plates (5), and the terminal on the other side of the heating element (7) is in contact with the terminal on the same side of the bipolar plate (1) below it through PTC plates (5), thus forming a temperature control circuit and a heating circuit.

2. The low-temperature self-controlled self-heating all-solid-state battery according to claim 1, characterized in that, The normal solid-state battery module includes a bipolar plate (1), a positive electrode active material layer (2), a solid electrolyte layer (3), and a negative electrode active material layer (4); the arrangement order of each layer includes: Sequence A: Bipolar plate - Positive electrode active material - Solid electrolyte - Negative electrode active material; Sequence B: Bipolar plate - Negative electrode active material - Solid electrolyte - Positive electrode active material; Multiple normal solid-state battery modules stacked in series are in the same order.

3. The low-temperature self-controlled self-heating all-solid-state battery according to claim 2, characterized in that, The bipolar plate (1) is made of Al, Cu, Ni, Ti or stainless steel SUS.

4. A low-temperature self-controlled self-heating all-solid-state battery according to claim 2, characterized in that, The material of the negative electrode active material layer (4) is lithium, sodium, potassium, or an alloy composed of multiple metals among these metals.

5. A low-temperature self-controlled self-heating all-solid-state battery according to claim 2, characterized in that, The solid electrolyte layer (3) is made of one or more combinations of perovskite, NASICON, LISICON, and garnet oxide solid electrolytes, or selected from glassy Li2S-P2S5, crystalline Li x M y PS z One or more of the following: glass-ceramic Li2S-P2S5 and Li6PSX5 sulfide solid electrolytes; or one or more combinations of PEO, PPC, PCL, PTMC, SN, PAN, MEEP polymer solid electrolytes; or one or more combinations of Li3MX6 halide solid electrolytes. Li x M y PS z In the formula, M is one or more of Si, Ge, and Sn, x+4y+5=2z, 0≤y≤1; In Li6PSX5, X = Cl, Br, I; In Li3MX6, M is a transition metal element, and X = F, Cl, Br, I, a halogen element.

6. A low-temperature self-controlled self-heating all-solid-state battery according to claim 2, characterized in that, The positive electrode active material layer (2) is composed of positive electrode active material powder, conductive agent, binder, and solid electrolyte particles; wherein, the positive electrode active material powder includes lithium cobalt oxide LiCoO2, lithium manganese oxide LiMnO2, and nickel-cobalt-manganese ternary lithium LiNi 1-x-y Co x Mn y One or more of the following: O2, lithium iron phosphate (LiFePO4), lithium manganese iron phosphate, and sulfur-containing positive electrode active materials; conductive agents including one or more combinations of carbon black conductive agent (SP), graphite conductive agent, and graphene conductive agent; binders including one or more combinations of polyvinylidene fluoride (PVDF), polyacrylonitrile (PAN), polymethyl methacrylate (PMMA), and styrene-butadiene rubber (SBR). Among them, nickel-cobalt-manganese ternary lithium LiNi 1-x-y Co x Mn y O2, where 0≤x≤0.5 and 0≤y≤0.

5.

7. A low-temperature self-controlled self-heating all-solid-state battery according to claim 2, characterized in that, The heating element (7) consists of a surface insulating material and an internal metal sheet. The insulating material completely wraps the metal sheet, with terminals extending only on both sides. The internal metal sheet is composed of a single metal or alloy of Ni, Pt, Cu, Fe, or Al.

8. A low-temperature self-controlled self-heating all-solid-state battery according to claim 2, characterized in that, The PTC sheet (5) is made of a switch-type positive temperature coefficient conductive composite material, which is composed of a polymer and a conductive filler.

9. A low-temperature self-controlled self-heating all-solid-state battery according to claim 2, characterized in that, The NTC sheet (6) is composed of two or more of the transition metal oxides V2O5, MnO2, Co2O3 or Al2O3 metal oxides using a ceramic sintering process, or is prepared by sol-gel method using V2O5 doped with Mo.

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