All-solid-state battery pressurization device

Abstract

We provide a pressurization device for all-solid-state batteries. [Solution] The device comprises a base on which a plurality of stacked solid-state battery cells are housed above the base; at least two pressure rods, the lower edges of which are locked to both sides of the base by fixing screws; a pressure plate installed above these solid-state battery cells, the sides of which are locked to the upper edges of the two pressure rods by fixing screws; at least two wedge-shaped pressing blocks, each pressed by anti-slip screws and attached to both sides of the upper edge of the pressure plate, the at least two wedge-shaped pressing blocks having an angle between the positive direction of the inclined surface of the wedge-shaped pressing block and the screw-in axis direction of the anti-slip screw; and a plurality of elastic interfaces installed between the base and the solid-state battery cells, between the plurality of solid-state battery cells, and between the solid-state battery cells and the pressure plate.

Description

Technical Field

[0001] The present invention relates to the technical field of all-solid-state battery manufacturing, and more particularly to an all-solid-state battery pressing device for measuring the degree of pressure applied to an all-solid-state battery cell.

Background Art

[0002] Lithium batteries are currently the mainstream power batteries adopted by major electric vehicle manufacturers worldwide. However, electric vehicle fires have been occurring one after another, leading to a situation where consumers are worried about the safety issues of electric vehicles. Taking Tesla as an example, it uses the most advanced battery technology manufactured by Panasonic in Japan, and its energy density is approaching the limit of conventional liquid lithium battery technology. However, the successive fire accidents may push the manufacturer into bankruptcy if they develop into lawsuits. Since the manufacturer is responsible for the design, it continues to pursue the development of batteries that enhance safety and meet the requirements in terms of functions.

[0003] In theory, all-solid-state batteries can solve the problems of current lithium batteries, especially two major problems in the power battery industry. That is, the safety problem and the energy density problem. The electrolyte of a general lithium battery is liquid, while the electrolyte used in an all-solid-state battery is solid. It prevents the problem of liquid leakage, and the solid electrolyte has the effect of strongly isolating the positive electrode and the negative electrode. Therefore, it is difficult to generate dendritic protrusions that lead to short circuits, and the safety is high. Regarding the energy density, because all-solid-state batteries have high safety, materials with higher energy density can be selected for the positive and negative electrodes. For example, lithium metal can be adopted for the negative electrode, or an NCMA mixture or the like can be adopted for the positive electrode, so that its energy density can exceed that of lithium ternary batteries. The solid electrolyte with the characteristics of incombustibility, non-corrosiveness, non-volatility, no liquid leakage, and heat resistance replaces the electrolyte solution and the separator, and fundamentally solves the problem of battery ignition.

[0004] However, solid-state lithium batteries also have limitations, and typical all-solid-state batteries were not suitable for high-speed charging and discharging. Since high-speed charging and discharging is an essential performance / operating environment when using vehicles such as electric cars and electric buses, it was necessary to overcome the characteristic that typical all-solid-state batteries are not suitable for high-speed charging and discharging by applying a certain amount of pressure (contact pressure) to the battery when assembling the battery unit to increase the charging and discharging speed of the all-solid-state battery. Because there are many types of all-solid-state battery cells, the amount of pressure applied also needs to be changed depending on the differences in the types and ratios of materials contained in different battery cells.

[0005] Conventional patent documents, for example, Patent Document 1 below, discloses an in-vehicle all-solid-state battery charging system characterized by comprising: a charging unit for charging the all-solid-state battery; a pressurizing unit for applying a restraining pressure to the all-solid-state battery; and a pressure control unit for controlling the restraining pressure, wherein the pressure control unit issues commands to the pressurizing unit to make the restraining pressure during charging higher than the restraining pressure during discharge. Such a design emphasizes continuously changing the restraining pressure on the battery during charging and discharging, requiring the installation of a separate pressure sensing device outside the battery, and further using a pressurizing device (pressurizing unit) whose applied pressure can be arbitrarily adjusted, resulting in a complex structure and control logic, increased cost of necessary components, and a larger volume. In addition, factors such as temperature and vibration during battery use (while the vehicle is running) all affected the control accuracy of immediate pressure adjustment. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Chinese Patent No. 10463810 Specification [Overview of the project] [Problems that the invention aims to solve]

[0007] Therefore, the inventors believed that the above-mentioned shortcomings could be improved, and after diligent research, arrived at the present invention, which effectively improves the above-mentioned problems through a rational design.

[0008] This invention has been made in view of the above circumstances, and one of its objectives is to solve the problems described above. Specifically, the present invention has a pressure plate, a wedge-shaped pressing block, an anti-slip screw, and a fixing screw, and is capable of pressurizing and adjusting the pressure value of an all-solid-state battery, effectively adjusting the pressure value required for the all-solid-state battery, reducing the volume of the pressurizing device, and achieving pressurization with a simple mechanism. [Means for solving the problem]

[0009] To solve the above problems, a solid-state battery pressurizing device according to one embodiment of the present invention comprises: a base on which a plurality of stacked solid-state battery cells are housed above the base; at least two pressurizing rods, the lower edges of which are locked to both sides of the base by fixing screws; a pressurizing plate installed above the solid-state battery cells, with both sides of which locked to the upper edges of the two pressurizing rods by fixing screws; at least two wedge-shaped pressing blocks, each pressed by anti-slip screws and attached to both sides of the upper edge of the pressurizing plate, the at least two wedge-shaped pressing blocks having an angle between the positive direction of the inclined surface of the wedge-shaped pressing block and the screw-in axis direction of the anti-slip screw; and a plurality of elastic interfaces installed between the base and the solid-state battery cells, between the plurality of solid-state battery cells, and on the solid-state battery cells and the pressurizing plate, respectively.

[0010] According to one aspect of the present invention, the angle between the positive direction of the inclined surface of the wedge-shaped pressing block and the threading axis of the anti-slip screw is in the range of 30 to 60 degrees.

[0011] According to one aspect of the present invention, the elastic interface is a PU foam pad or an elastic rubber pad.

[0012] According to one aspect of the present invention, the wedge-shaped pressing block is made of metal.

[0013] According to one aspect of the present invention, the outer side of the upper edge of the pressure plate has a receding angle.

[0014] Other objects, structures, and effects of the present invention will become apparent from the following section on embodiments of the invention. [Brief explanation of the drawing]

[0015] [Figure 1] This is a schematic diagram showing a solid-state battery pressurization device according to a first embodiment of the present invention. [Figure 2] This is a schematic diagram showing a solid-state battery pressurization device according to a first embodiment of the present invention. [Modes for carrying out the invention]

[0016] Embodiments of the present invention will be described in detail below. However, the present invention is not limited thereto, and various modifications are possible within the scope described. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included within the technical scope of the present invention.

[0017] In the first and second embodiments of the present invention, as well as in the drawings, "upper" and "lower" refer to the upper and lower directions as described in the drawings of the specification, and the pressure plate, all-solid-state battery cell, and base are in a sequential relative positional relationship from top to bottom.

[0018] (First embodiment) Figure 1 is a schematic diagram showing a solid-state battery pressurization device according to a first embodiment of the present invention. The above embodiment comprises a base 11, on which a plurality of stacked solid-state battery cells 11A are housed above the base 11; two pressure rods 12, the lower edges of which are locked to the base 11 on both sides by fixing screws 12A; a pressure plate 13, which is installed above the solid-state battery cells 11A and whose sides are locked to the upper edges of the two pressure rods 12 on both sides by fixing screws 12A; two wedge-shaped pressing blocks 14, which are pressed by anti-slip screws 14A and attached to the upper edges of the pressure plate 13, the two wedge-shaped pressing blocks 14, which are located above the fixing screws on the upper edges of the pressure rods 12; and a plurality of elastic interfaces 15, which are installed between the base 11 and the solid-state battery cells 11A, between the plurality of solid-state battery cells 11A, and between the solid-state battery cells 11A and the pressure plate 13.

[0019] In this embodiment, the base, pressure rod, and pressure plate are locked together by fixing screws to form a frame-type pressure device. In this embodiment, the locking force of the base and pressure rod (locking pressure of the fixing screws) is constant, and it is necessary to adjust the pressure to bias different types of solid-state battery cells. This is adjusted using the pressure plate, pressure rod, wedge-shaped pressing block, and anti-slip screws. The user adjusts the pressure value for multiple solid-state battery cells by rotating the anti-slip screws to apply pressure to the wedge-shaped pressing block and transmitting the pressure to the pressure plate.

[0020] (Second example) Figure 2 is a schematic diagram showing a solid-state battery pressurization device according to a second embodiment of the present invention. As shown in the figure, the pressure adjustment function of the wedge-shaped pressing block and anti-slip screw of the present invention will be explained. The pressurization rod 12 and the pressurization plate 13 are locked together by a fixing screw 12A, and the direction in which the fixing screw 12A is screwed in is perpendicular to the direction in which the pressurization plate 13 biases pressure on the solid-state battery cell 11A. Therefore, when the fixing screw is screwed in, the pressurization plate cannot be moved downward (pressurized), and the pressure on the solid-state battery cell becomes a fixed value that cannot be adjusted. However, if the screwing direction of the fixing screw 12A is modified to be the same as the direction in which the pressure plate 13 biases pressure on the all-solid-state battery cell 11A (for example, screwing the fixing screw from the top to the bottom of the pressure plate), the biasing pressure of the pressure plate (distance from the bottom plate) is determined entirely by the screwing length of the fixing screw, and multiple fixing screws in different positions, differences in operation by different operators, etc., all affect the accuracy of the pressurization, making it difficult to adjust to the optimal pressurization value for the all-solid-state battery cell. Therefore, in the present invention, a wedge-shaped pressing block 14 is installed above the pressure plate 13, and anti-slip screws 14A are installed on the side of the wedge-shaped pressing block 14 (parallel to the fixing screw 12A and located above the fixing screw 12A), and the receding angle ψ on the outside of the upper edge of the pressure plate 13 is the same as the angle between the normal direction of the inclined surface of the wedge-shaped pressing block 14 and the axial direction of the screwing direction of the anti-slip screw 14A. When a user operates the solid-state battery pressurizing device according to the present invention, they first screw in the anti-slip screw 14A to a specific length, which pushes and displaces the wedge-shaped pressing block 14 (in the same direction as the screwing axis) and compresses the outer side of the upper edge of the pressurizing plate 13. The resulting normal force on the inclined surface creates pressure on the pressurizing plate 13. After the anti-slip screw and wedge-shaped pressing block adjust to the optimal pre-pressurization for the solid-state battery cells targeting the pressurizing plate, the user screws in the fixing screw located below to lock it, thereby applying a constant pressure to the solid-state battery cells inside the solid-state battery pressurizing device according to the present invention.

[0021] In this embodiment, based on the pressurization pressure value (elastic interface compression amount) required for the all-solid-state battery, wedge-shaped pressing blocks with different angles are used. The retreat angle outside the upper edge of the pressure plate is preferably in the range of 30 degrees to 60 degrees. For example, when the retreat angle outside the upper edge of the pressure plate is 30 degrees, and in this embodiment, when adjusting the pressure value (compression amount) with a locking screw, when the locking screw is screwed in by 1 mm, the upper plate is pushed down by about 1.73 mm. When the retreat angle outside the upper edge of the pressure plate is 45 degrees, and in this embodiment, when adjusting the pressure value (compression amount) with a locking screw, when the locking screw is screwed in by 1 mm, the upper plate is pushed down by about 1 mm. When the retreat angle outside the upper edge of the pressure plate is 60 degrees, and in this embodiment, when adjusting the pressure value (compression amount) with a locking screw, when the locking screw of 1.73 mm is screwed in, the upper plate is pushed down by about 1 mm.

[0022] In this embodiment, if one battery cell with a charging expansion amount of 0.6 mm is adopted, when seven battery cells are stacked in series connection and pressurized, a total of 4.2 mm of relaxation amount (stress relaxation) is required to stack the seven battery cells. The elastic interface absorbs this expansion amount to prevent a rapid increase in pressure. Between the pressure plate and the battery cell, between the battery cells, and between the battery cell and the bottom plate, PU foam pads (model number 60 - 20125) are added to provide an interval for the elastic interface when pressurizing the battery cell. There are a total of eight PU foam pads, each with a thickness of 3.18 mm, and the total thickness is 25.44 mm. The all-solid-state battery pressurization device according to the present invention pressurizes the entire battery module (a plurality of battery cells), compresses the eight PU foam pads to a total thickness of 3.64 mm, and provides a pre-pressure of 0.3 MPa. When the battery is charged, the total expansion amount of the battery cell is 4.2 mm, and the pressure generated by the all-solid-state battery pressurization device according to the present invention pre-pressurizing the PU foam pads finally reaches an equilibrium pressure of 0.5 MPa.

[0023] In this embodiment, since it is necessary to pressurize all-solid-state battery cells with different formulations and different amounts of expansion of the battery cells, the present invention designs the angle of the inclined plane that contracts inside the upper edge of the pressure plate (the angle design between the combined wedge-shaped push block and the anti-slip screw), selects elastic interfaces with different stress-strain curve parameters (for example, PU foam pads, elastic rubber pads), and realizes the pressurization and pressure regulation required for all-solid-state batteries.

[0024] In this embodiment, the wedge-shaped push block is made of metal and has high strength. Users can select wedge-shaped push blocks with different materials considering factors such as insulation, strength, and cost.

[0025] Incidentally, in the embodiments of the present invention, a pressurizing device is configured by combining the arrangement of the base, the pressure plate above it, the wedge-shaped push block, and the anti-slip screw above it. Users can change the upper pressure plate of the present invention to a lower pressure plate (fixed above) according to their own needs, or may have a pressure plate that can adjust the pressure both above and below, or may change to a design that pressurizes from the left and right side directions. The quantity and locking position of the wedge-shaped push block and the anti-slip screw are also variable and are not limited to the content described in the specification of the present invention.

[0026] Thereby, the all-solid-state battery pressurizing device according to the present invention utilizes the pressurizing mechanism of the pressure plate, the wedge-shaped push block, and the anti-slip screw to apply an appropriate constant pre-pressure to all-solid-state batteries (battery cells) that is optimal for the type of battery, improving the charge and discharge performance and safety of the battery. The present invention effectively limits the pressurizing pressure value required for all-solid-state batteries according to parameters such as the pre-pressure amount, the expansion amount of the battery cell, and the stress-strain curve of the elastic interface, confines the pressure within a suitable operating pressure range for the known type of battery cell, and prevents a sharp rise in the pressure generated during the expansion of the battery cell. The present invention reduces and simplifies the pressure control logic and the volume of the device required for pressurizing all-solid-state batteries, and has both functionality and economic effects.

[0027] The present invention is not limited to the embodiments described above, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention. [Explanation of symbols]

[0028] 11 Bass 11A All-Solid-State Battery Cell 12 Pressure Rod 12A Fixing Screw 13 Pressure Plate 14 Wedge-shaped pressing block 14A Anti-slip screws 15 Elastic Interface ψ Receding angle

Claims

1. A base, wherein a plurality of stacked solid-state battery cells are housed above the base, At least two pressure rods, the lower edges of the two pressure rods being locked to both sides of the base by fixing screws, A pressure plate is installed above these all-solid-state battery cells, and both sides of it are locked to the upper edges of the two pressure rods by fixing screws, At least two wedge-shaped pressing blocks, each pressed by an anti-slip screw and attached to both sides of the upper edge of the pressure plate, wherein the at least two wedge-shaped pressing blocks have an angle between the positive direction of the inclined surface of the wedge-shaped pressing block and the screw-in axis direction of the anti-slip screw, A solid-state battery pressurizing device characterized by comprising a plurality of elastic interfaces installed between the base and the solid-state battery cell, between a plurality of solid-state battery cells, and between the solid-state battery cell and the pressurizing plate.

2. The all-solid-state battery pressurizing device according to claim 1, characterized in that the angle between the positive direction of the inclined surface of the wedge-shaped pressing block and the threading axis of the anti-slip screw is in the range of 30 degrees to 60 degrees.

3. The all-solid-state battery pressurizing device according to claim 1, characterized in that the elastic interface is a PU foam pad or an elastic rubber pad.

4. The all-solid-state battery pressurizing device according to claim 1, characterized in that the wedge-shaped pressing block is made of metal.

5. The all-solid-state battery pressurizing device according to claim 1, characterized in that the outer side of the upper edge of the pressurizing plate has a receding angle.

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