All-solid-state battery and control method for all-solid-state battery

Abstract

This all-solid-state battery comprises a battery portion, a first pressure-applying mechanism that applies pressure to the battery portion, a second pressure-applying mechanism that operates independently of the first pressure-applying mechanism, a first pressure-reducing mechanism that reduces the pressure applied by the first pressure-applying mechanism, and a second pressure-reducing mechanism that operates independently of the first pressure-reducing mechanism and reduces the pressure applied by the second pressure-applying mechanism. The first pressure-applying mechanism includes an elastic body.

Description

All-solid-state battery and method for controlling all-solid-state battery

[0001] The present invention relates to an all-solid-state battery and a method for controlling the all-solid-state battery.

[0002] All-solid-state batteries are secondary batteries that primarily use solid electrolytes. In all-solid-state batteries, the battery cells are compressed with a large force to reduce contact resistance.

[0003] A technology related to pressurizing batteries is described, for example, in Patent Document 1 (JP2019-114477A), which discloses "a battery module having a plurality of stacked batteries and a restraining component that restrains the plurality of batteries, the restraining component being composed of a pair of end plates arranged at both ends of the plurality of batteries in the stacking direction and a tension band that connects the pair of end plates and restrains the plurality of batteries in a pressurized state, the tension band having elastically deformable concave and convex portions."

[0004] The present inventors have been studying all-solid-state batteries that use metallic lithium as the negative electrode active material, and have been considering using an elastic body such as a rubber band as a pressure mechanism in such all-solid-state batteries.

[0005] In all-solid-state batteries using metallic lithium as the negative electrode active material, metallic lithium may melt if the temperature becomes abnormally high. Metallic lithium is highly reactive. Therefore, even if the temperature becomes abnormally high, it is desirable to prevent leakage of molten metallic lithium.

[0006] The inventors are investigating reducing the pressure applied when temperatures are abnormally high to prevent leakage of metallic lithium. Reducing the pressure makes it more difficult for molten metallic lithium to be extruded from the battery cell, which is expected to prevent leakage.

[0007] However, the pressure mechanism usually has the function of not only reducing contact resistance but also improving vibration resistance, etc. In other words, by restraining the battery part with the pressure mechanism, it prevents multiple components from scattering, etc. If the pressure is completely released, vibration resistance, etc. will also be impaired.

[0008] Therefore, the inventors have considered controlling the pressure in accordance with the temperature. Specifically, when the temperature reaches a certain high level, the pressure is reduced to a certain extent within a range that ensures vibration resistance, etc. Then, when the temperature rises further to a level that melts the metallic lithium, the pressure is further reduced (or removed). However, in order to perform such control, the pressure must be reduced in multiple stages. If an elastic body is simply used as the pressure mechanism, it is difficult to reduce the pressure in multiple stages.

[0009] Therefore, an object of the present invention is to provide a technology that can reduce the pressure in multiple stages in an all-solid-state battery that uses an elastic body as a pressure mechanism.

[0010] In one aspect of the present invention, an all-solid-state battery includes a battery unit including a battery cell using metallic lithium as a negative electrode active material, a first pressurizing mechanism that pressurizes the battery unit, a second pressurizing mechanism that operates independently of the first pressurizing mechanism and pressurizes the battery unit, a first decompression mechanism that reduces the pressure applied by the first pressurizing mechanism, and a second decompression mechanism that operates independently of the second pressurizing mechanism and reduces the pressure applied by the second pressurizing mechanism. The first pressurizing mechanism includes an elastic body.

[0011] FIG. 1 is a diagram schematically showing the configuration of an all-solid-state battery according to a first embodiment. FIG. 2 is a diagram schematically showing main parts of an all-solid-state battery according to a modified example of the first embodiment. FIG. 3 is a diagram schematically showing an all-solid-state battery according to a second embodiment. FIG. 4 is a diagram showing another example of an actuator. FIG. 5 is a diagram functionally showing the configuration of an all-solid-state battery according to a third embodiment. FIG. 6 is a flowchart showing a control method for an all-solid-state battery according to a third embodiment. FIG. 7 is a flowchart showing a control method for an all-solid-state battery according to a fourth embodiment. FIG. 8 is a diagram schematically showing the relationship between the control content of an all-solid-state battery, the charge amount, and the temperature of a battery cell. FIG. 9 is a schematic diagram showing an example of a battery cell.

[0012] Hereinafter, an all-solid-state battery according to an embodiment of the present invention will be described with reference to the drawings. The application of the all-solid-state battery 1 according to this embodiment is not particularly limited, but it can be used for, for example, an electric vehicle.

[0013] In this specification, the term "all-solid-state battery" refers to a battery in which a solid electrolyte is mainly used as the electrolyte in the electrolyte layer, the positive electrode layer, the negative electrode layer, etc., but a small amount of a liquid electrolyte may also be used in addition to the solid electrolyte.

[0014] (1) First Embodiment Fig. 1 is a diagram schematically illustrating the configuration of an all-solid-state battery 1 according to a first embodiment. Fig. 1(a) illustrates the configuration during normal operation. As shown in Fig. 1(a), the all-solid-state battery 1 includes a battery section 2, a first pressurizing mechanism 4, a second pressurizing mechanism 5, a first decompression mechanism 6, a second decompression mechanism 7, fixed end plates 11-1 and 11-2, a movable end plate 12, and a frame 13.

[0015] The battery section 2 is a section that realizes the charge / discharge function. Although not shown, the battery section 2 has at least one battery cell. In the battery cell, metallic lithium is used as the negative electrode active material. The battery cell is configured so that, during charging, lithium ions move from the positive electrode to the negative electrode, and metallic lithium is deposited on the negative electrode. During discharging, the metallic lithium deposited on the negative electrode moves to the positive electrode as lithium ions and is absorbed by the positive electrode.

[0016] The battery module 2 is sandwiched between a fixed end plate 11-1 and a movable end plate 12. Furthermore, a fixed end plate 11-2 is provided on the outer side of the movable end plate 12. The fixed end plate 11-1 and the fixed end plate 11-2 are connected via a frame 13.

[0017] The first pressure mechanism 4 and the second pressure mechanism 5 are each provided to apply pressure to the battery unit 2. In the all-solid-state battery 1, the battery unit 2 (battery cells) needs to be compressed and pressurized to obtain desired battery characteristics. The first pressure mechanism 4 and the second pressure mechanism 5 compress the battery unit 2 so as to obtain the desired battery characteristics. These pressure mechanisms are also provided to maintain the vibration resistance of the battery unit 2. For example, when the all-solid-state battery 1 is used in an automobile, it is expected that the battery unit 2 will be subjected to vibration. There is a concern that components may be dispersed due to vibration. For example, if multiple battery cells are included in the battery unit 2, the multiple battery cells may be dispersed. By restraining the battery unit 2 with the first pressure mechanism 4 and the second pressure mechanism 5, vibration resistance is maintained and dispersion of components is prevented.

[0018] The first pressure mechanism 4 and the second pressure mechanism 5 are independent. Specifically, the first pressure mechanism 4 and the second pressure mechanism 5 each have an elastic body (e.g., rubber). The use of an elastic body allows the pressure mechanism to be made smaller and lighter. In the example shown in FIG. 1 , two elastic bodies function as the first pressure mechanism 4, and the other two elastic bodies function as the second pressure mechanism 5. Each elastic body is disposed in a compressed state between the movable end plate 12 and the fixed end plate 11-2. One end of each elastic body is connected to the movable end plate 12, and the other end is connected to the fixed end plate 11-2. This applies pressure to the battery module 2.

[0019] The first decompression mechanism 6 and the second decompression mechanism 7 are provided corresponding to the first pressurization mechanism 4 and the second pressurization mechanism 5. The first decompression mechanism 6 and the second decompression mechanism 7 operate independently of each other.

[0020] The first decompression mechanism 6 is configured to reduce the pressure applied by the first pressure mechanism 4. The second decompression mechanism 7 is configured to reduce the pressure applied by the second pressure mechanism 5. Specifically, the first decompression mechanism 6 and the second decompression mechanism 7 are configured to cut the elastic body included in the corresponding pressure mechanism. The first decompression mechanism 6 and the second decompression mechanism 7 can be realized by a cutting mechanism such as a cutter, for example.

[0021] Next, a method of operating the all-solid-state battery 1 according to this embodiment will be described.

[0022] As shown in Fig. 1(a), under normal circumstances, the battery module 2 is pressurized by a first pressurizing mechanism 4 and a second pressurizing mechanism 5. This allows the battery module 2 to be charged or discharged as needed.

[0023] On the other hand, if the temperature of the battery module 2 rises above the normal range, a first-stage pressure reduction is performed. Specifically, as shown in FIG. 1B, the elastic body included in the second pressure mechanism 5 is cut. That is, the second pressure reduction mechanism 7 is operated to cut the elastic body included in the second pressure mechanism 5. This reduces (releases) the pressure applied by the second pressure mechanism 5. As a result, the total pressure applied to the battery module 2 is reduced. As the pressure is reduced, the battery reaction in the battery module 2 becomes less likely to proceed, and heat generation in the battery module 2 is suppressed. Meanwhile, pressure is still applied to the battery module 2 by the first pressure mechanism 4. Therefore, a certain degree of vibration resistance is maintained.

[0024] Here, when the temperature of the battery module 2 further rises and reaches a temperature at which metallic lithium can melt, a second stage of decompression is performed. Specifically, as shown in FIG. 1( c), the elastic body included in the first pressure mechanism 4 is cut. That is, the first pressure reduction mechanism 6 is operated, and the pressure applied by the first pressure mechanism 4 is reduced. This further reduces the pressure applied to the battery module 2. In this embodiment, the pressure is released. If the pressure applied to the battery module 2 is small, even if metallic lithium is melted, it is unlikely to leak to the outside. Therefore, leakage of metallic lithium to the outside is prevented.

[0025] As described above, according to this embodiment, two systems of pressurizing mechanisms that operate independently and two systems of corresponding decompression mechanisms are provided, so that the pressurizing force can be reduced in multiple stages even while using an elastic body as the pressurizing mechanism, thereby preventing leakage of metallic lithium while maintaining as much vibration resistance as possible.

[0026] (Modification) Next, a modification of the first embodiment will be described. FIG. 2 is a schematic diagram showing the main parts of an all-solid-state battery 1 according to this modification. In this modification, the positions of the first pressure mechanism 4 and the second pressure mechanism 5 are changed. Specifically, the elastic bodies included in these pressure mechanisms are disposed between the fixed end plate 11-1 and the movable end plate 12. Each elastic body is disposed in a stretched state. This applies pressure so that the battery module 2 is compressed between the fixed end plate 11-1 and the movable end plate 12. All other points are the same as those in the example shown in FIG. 1 . Even when such a configuration is adopted, the pressure can be reduced in multiple stages by using two systems of pressure mechanism and pressure reduction mechanism, respectively.

[0027] (2) Second Embodiment Next, a second embodiment will be described. Note that detailed description of the second embodiment will be omitted for the fact that the same configuration as the first embodiment can be adopted.

[0028] 3 is a schematic diagram showing the all-solid-state battery 1 according to this embodiment. In this embodiment, the configurations of the second pressurizing mechanism 5 and the second decompression mechanism 7 are modified.

[0029] As shown in Fig. 3, the all-solid-state battery 1 has an actuator 16. This actuator 16 functions as the second pressurizing mechanism 5 and the second decompression mechanism 7. Specifically, the all-solid-state battery 1 has a case 14 provided to cover the battery module 2 and the movable end plate 12. The actuator 16 is provided between the movable end plate 12 and the inner surface of the case 14. One end of the actuator 16 is supported by the case 14, and the other end is in contact with the movable end plate 12. In a normal state, the actuator 16 presses the movable end plate 12. As a result, the battery module 2 is pressurized by the actuator 16.

[0030] On the other hand, the first pressure mechanism 4 is an elastic body disposed between the fixed end plate 11-1 and the movable end plate 12, as in the modified example of the first embodiment.

[0031] In this modification, the pressure applied to the battery module 2 can also be reduced in multiple stages. Specifically, during the first stage of pressure reduction, the actuator 16 is operated to reduce the pressure applied to the battery module 2. In other words, it can be said that the actuator 16 functions not only as the second pressure mechanism 5 but also as the second pressure reduction mechanism 7.

[0032] On the other hand, during the second stage of decompression, the elastic body included in the first pressurizing mechanism 4 is cut by the first decompression mechanism 6 .

[0033] As described above, according to this embodiment, the pressure can be reduced in multiple stages, similar to the previously described embodiments.

[0034] In addition, according to the present embodiment, when the abnormal state is resolved after the first-stage depressurization, pressure can be applied again by operating the actuator 16. Therefore, the operation of the all-solid-state battery 1 can be continued.

[0035] On the other hand, during the second stage of decompression, it is desirable to release the pressure quickly to prevent leakage of the metallic lithium. According to this embodiment, the pressure is released by cutting the elastic body in the second stage. This allows the pressure to be released more quickly than when an actuator is operated. Therefore, leakage of the metallic lithium can be more reliably prevented.

[0036] Note that the specific example of the actuator 16 is not particularly limited. For example, an actuator having a hydraulic cylinder or a gas cylinder can be used as the actuator 16. Fig. 4 is a diagram showing another example of the actuator 16. As shown in Fig. 4, an actuator having a motor 17 and a feed screw 18 can also be used as the actuator 16.

[0037] (3) Third Embodiment Next, a third embodiment will be described. Note that detailed description will be omitted for the fact that the same configuration as the previously described embodiments can be adopted.

[0038] In this embodiment, a control method for the all-solid-state battery 1 will be described. Fig. 5 is a diagram functionally illustrating the configuration of the all-solid-state battery 1 according to this embodiment. As in the previously described embodiments, the all-solid-state battery 1 includes a battery section 2 having a battery cell 3, a first pressurizing mechanism 4, a second pressurizing mechanism 5, a first decompression mechanism 6, and a second decompression mechanism 7. In addition, in this embodiment, a control device 8, a measurement mechanism 9, and a discharge mechanism 10 are added.

[0039] The measurement mechanism 9 is configured to measure the state of the battery module 2. Specifically, the measurement mechanism 9 is configured to measure the temperature of the battery cells 3 included in the battery module 2.

[0040] The discharge mechanism 10 is configured to discharge the battery cell 3. The discharge mechanism 10 can be realized by, for example, a load circuit connected to the battery cell 3.

[0041] The control device 8 is configured to acquire temperature data from the measurement mechanism 9 and control the operation of the all-solid-state battery 1 based on the acquired temperature data. The control device 8 is realized by a computer such as a microcomputer. That is, the control device 8 includes a storage device such as a memory that stores a control program, and an arithmetic device such as a CPU that executes the control program. The functions of the control device 8 are realized by the arithmetic device executing the control program.

[0042] 6 is a flowchart showing a control method for the all-solid-state battery 1. The control method for the all-solid-state battery 1 will be described in detail with reference to FIG.

[0043] (Step S10) The control device 8 monitors the temperature of the battery cells 3. That is, the control device 8 acquires temperature data from the measurement mechanism 9, for example, periodically.

[0044] (Step S20) After acquiring the temperature data, the control device 8 compares the temperature of the battery cell 3 with a preset first temperature T1. The first temperature T1 is a temperature that serves as a criterion for determining whether or not an abnormal temperature rise has occurred. The first temperature T1 is set, for example, within a range of 100 to 150°C. The first temperature T1 may be, for example, a temperature at which the control device 8 determines that an abnormal temperature rise has occurred and notifies the user of the abnormal temperature rise via an alarm mechanism (not shown), such as a lamp.

[0045] (Step S30) If the temperature of the battery cell 3 is equal to or lower than the first temperature T1, it can be said that the battery cell 3 is in a normal state. Therefore, the control device 8 does not perform any special processing. That is, the all-solid-state battery 1 is operated in a normal operation.

[0046] (Step S40) On the other hand, if the temperature of the battery cell 3 exceeds the first temperature T1, the control device 8 further compares the temperature of the battery cell 3 with a preset second temperature T2. The second temperature T2 is a temperature higher than the first temperature T1 and is set from the perspective of determining whether or not metallic lithium melts. The second temperature T2 is set to a value within a range of, for example, 150 to 210°C, preferably 160 to 200°C.

[0047] (Step S50) If the temperature of the battery cell 3 is equal to or lower than the second temperature T2 in step S40, the control device 8 performs a first stage of depressurization. Specifically, the second depressurization mechanism 7 reduces (or removes) the pressure applied by the second pressure mechanism 5. The control device 8 also causes the discharge mechanism 10 to discharge the battery cell 3.

[0048] This step reduces the pressure applied to the battery cells 3. As a result, as described above, the battery reaction in the battery cells 3 is less likely to proceed. This suppresses heat generation. Meanwhile, the battery module 2 is still pressurized (restrained) by the first pressure mechanism 4. Because a certain level of restraining pressure is maintained, vibration resistance is ensured.

[0049] Furthermore, by discharging the battery cell 3 in this step, metallic lithium present in the negative electrode moves to the positive electrode and is absorbed into the positive electrode. Lithium absorbed into the positive electrode usually does not melt. In other words, by discharging, the amount of metallic lithium that can melt is reduced before the temperature of the battery cell 3 reaches the melting temperature of metallic lithium.

[0050] (Step S60) On the other hand, if the temperature of the battery cell 3 exceeds the second temperature T2 in step S40, the control device 8 performs a second stage of pressure reduction. Specifically, the first pressure reduction mechanism 6 reduces the pressure applied by the first pressure mechanism 4. Preferably, the pressure applied by the first pressure mechanism 4 is released. In other words, the pressure applied to the battery section 2 is released. If the temperature of the battery cell 3 exceeds the second temperature T2, it is believed that the metallic lithium is molten. If the battery cell 3 is constrained in a molten state, the molten metallic lithium is likely to leak to the outside of the battery cell 3. In contrast, by reducing (or releasing) the pressure in this step, metallic lithium is less likely to leak to the outside, even if it is molten.

[0051] In addition, since the discharging operation cannot be performed when the metallic lithium is in a molten state, the control device 8 does not perform the discharging operation in step 60.

[0052] The third embodiment has been described above. According to this embodiment, the battery cell 3 is discharged before the temperature reaches the melting point of metallic lithium (step S50). This reduces the amount of metallic lithium that may leak before the metallic lithium melts, thereby more reliably preventing leakage of metallic lithium.

[0053] (4) Fourth Embodiment Next, a fourth embodiment will be described. This embodiment can be considered a modification of the third embodiment. Detailed description of the fact that the same configuration as the third embodiment can be adopted will be omitted.

[0054] In this embodiment, the control device 8 (see FIG. 5 ) controls the operation of the all-solid-state battery 1 by referring to the charge amount of the battery cell 3 in addition to the temperature of the battery cell 3. That is, the measurement mechanism 9 (see FIG. 5 ) is configured to detect the charge amount (e.g., SOC) of the battery cell 3 in addition to the temperature of the battery cell 3. Note that "detecting the charge amount" also includes detecting the charge amount by "estimating" it. For example, the measurement mechanism 9 may detect the charge amount by estimating the SOC of the battery cell 3 from the voltage or the like. The measurement mechanism 9 is configured to generate charge amount data indicating the detected charge amount in addition to the temperature data, and notify the control device 8 of the charge amount data.

[0055] Fig. 7 is a flowchart showing a control method for the all-solid-state battery 1 according to this embodiment. Fig. 8 is a diagram schematically showing the relationship between the control content of the all-solid-state battery 1, the charge amount, and the temperature of the battery cell 3. In this embodiment, steps S21 to S23 are added to the third embodiment. Each step will be described in detail below.

[0056] (Steps S10 to S30) Steps S10 to S30 are the same as those in the third embodiment (see FIG. 6). That is, in step S10, the control device 8 detects the temperature of the battery cell 3. In step S20, the control device 8 compares the temperature of the battery cell 3 with a first temperature T1. If the temperature of the battery cell 3 is equal to or lower than the first temperature T1, the control device 8 operates the all-solid-state battery 1 in normal operation (step S30).

[0057] (Steps S21-22) On the other hand, if the temperature of the battery cell 3 is higher than the first temperature T1, the charge amount of the battery cell 3 is detected. That is, the control device 8 acquires charge amount data via the measurement mechanism 9 (step S21). Then, the control device 8 compares the charge amount of the battery cell 3 with a preset first charge amount A (%) (step S22).

[0058] (Steps S40 to S60) The operations when the charge amount of the battery cell 3 is equal to or greater than the first charge amount A are basically the same as steps S40 to S60 in the third embodiment. That is, the control device 8 compares the temperature of the battery cell 3 with the second temperature T2 (step S40). When the temperature of the battery cell 3 is equal to or less than the second temperature T2, the control device 8 performs a first stage of pressure reduction and causes the discharge mechanism 10 to discharge the battery cell 3 until the temperature becomes less than the first charge amount A (step S50). On the other hand, when the temperature of the battery cell 3 is greater than the second temperature T2, the control device 8 performs a second stage of pressure reduction. Furthermore, the discharge mechanism 10 does not perform a discharging operation (step S60).

[0059] (Step S23) On the other hand, if the charge amount of the battery cell 3 is less than the first charge amount A in step S22, the control device 8 performs the first stage of pressure reduction. On the other hand, the control device 8 does not perform the discharge process.

[0060] The above is the control method for the all-solid-state battery 1 according to this embodiment. According to this embodiment, when the charge amount of the battery cell 3 exceeds the first charge amount A, the operation of the all-solid-state battery 1 is controlled in the same manner as in the third embodiment. This prevents leakage of molten lithium metal, similar to the third embodiment.

[0061] On the other hand, when the charge amount of the battery cell 3 is low (i.e., when it is less than the first charge amount A), the battery cell 3 is not discharged even if the temperature of the battery cell 3 exceeds the first temperature T1 (step S23). Therefore, a certain amount of power is secured. For example, when the all-solid-state battery 1 is mounted on a vehicle, if a discharge process is performed during an abnormal temperature rise and the battery cell 3 loses all power, it may not be possible to secure the power necessary for evacuation of the vehicle, etc. In contrast, according to the present embodiment, when the charge amount is less than the first charge amount A, a discharge process is not performed, so a certain amount of power is secured for evacuation of the vehicle, etc. Note that when the charge amount of the battery cell 3 is low, the amount of metallic lithium that can melt is small, and therefore, even if the temperature of the battery cell 3 subsequently reaches the melting temperature of metallic lithium, the possibility of leakage is low.

[0062] Furthermore, in this embodiment, when the charge level of the battery cell 3 is less than the first charge level A, the battery cell 3 is pressurized to a certain degree even if the temperature exceeds the second temperature T2 (step S23). As described above, when the charge level of the battery cell 3 is less than the first charge level A, the amount of metallic lithium that can melt is small. Therefore, even if the battery cell 3 is constrained, the possibility of metallic lithium leaking to the outside is low. Because the battery cell 3 is constrained under conditions where the possibility of leakage is low, vibration resistance is ensured.

[0063] The first charge amount A is set to a value that prevents the amount of metallic lithium contained in the negative electrode from leaking to the outside. This point will be described in detail below.

[0064] 9 is a schematic diagram showing an example of a battery cell 3 according to this embodiment. This battery cell 3 is housed in a film-like exterior body 15. A buffer space 19 is provided inside the exterior body 15 between the exterior body 15 and the battery cell 3. With this configuration, even if some metallic lithium melts, the molten metallic lithium is contained in the buffer space 19 and does not reach the outside of the exterior body 15.

[0065] As described above, the amount of metallic lithium that can melt, i.e., the amount of metallic lithium contained in the negative electrode, varies depending on the charge / discharge state of the battery cell 3. Specifically, the amount of metallic lithium contained in the negative electrode increases during charging and decreases during discharging. Therefore, the first charge amount A is set to a charge amount that ensures that the amount of metallic lithium contained in the negative electrode is an amount that can be accommodated in the buffer space 19. If the first charge amount A is set to such a value, when the temperature of the battery cell 3 abnormally rises (exceeds the first temperature T1), the charge amount of the battery cell 3 is reduced until the amount of metallic lithium contained in the negative electrode falls within the range that can be accommodated in the buffer space 19. Therefore, even if the battery cell 3 subsequently reaches a temperature at which metallic lithium melts, the molten metallic lithium can be accommodated in the buffer space 19, preventing leakage to the outside.

[0066] More preferably, the first charge amount A is set to the maximum value among the charge amounts at which the amount of metallic lithium deposited on the negative electrode is an amount that can be accommodated in the buffer space 19. If the first charge amount A is set to such a value, vibration resistance is maintained to the maximum extent as long as the amount of metallic lithium in the negative electrode is an amount that can be accommodated in the buffer space 19. Furthermore, electric power can be used up to the temperature at which metallic lithium melts (second temperature T2).

[0067] The fourth embodiment has been described above. In this embodiment, the first stage of depressurization is performed in step S23. However, in step S23, depressurization may not be performed and the battery module 2 may be pressurized with the same pressure as during normal operation.

[0068] The present invention has been described above with reference to the first to fourth embodiments. Representative configurations of the present invention and their effects will be summarized below as supplementary notes.

[0069] (Supplementary Note 1) An all-solid-state battery 1 includes: a battery section 2 including a battery cell using metallic lithium as a negative electrode active material; a first pressurizing mechanism 4 that pressurizes the battery section 2; a second pressurizing mechanism 5 that operates independently of the first pressurizing mechanism 4 and pressurizes the battery section 2; a first decompression mechanism 6 that reduces the pressure applied by the first pressurizing mechanism 4; and a second decompression mechanism 7 that operates independently of the first decompression mechanism 6 and reduces the pressure applied by the second pressurizing mechanism 5, wherein the first pressurizing mechanism 4 includes an elastic body.

[0070] According to this configuration, since two systems of pressurizing mechanisms that operate independently and two systems of decompression mechanisms that operate independently are provided, decompression can be performed in multiple stages.

[0071] (Supplementary Note 2) The all-solid-state battery according to Supplementary Note 1, wherein the second pressure mechanism 5 includes an actuator.

[0072] According to this configuration, the second pressurizing mechanism 5 can apply pressure again after performing a decompression process once, so that the operation of the all-solid-state battery can be continued when the abnormal state is resolved.

[0073] (Supplementary Note 3) A control method for the all-solid-state battery according to Supplementary Note 1 or 2, comprising: a step (S10) of detecting the temperature of the battery cell 3; a step (S50) of reducing the pressure applied by the second pressurizing mechanism 5 via the second decompression mechanism 7 when the temperature of the battery cell 3 exceeds a predetermined first temperature T1; and a step (S60) of reducing the pressure applied by the first pressurizing mechanism 4 via the first decompression mechanism 6 when the temperature of the battery cell 3 exceeds a predetermined second temperature T2 that is higher than the first temperature T1.

[0074] According to this method, when the temperature reaches a certain level, the first stage of pressure reduction can suppress the progress of the battery reaction and suppress heat generation while maintaining vibration resistance, and when the temperature reaches a higher level, the second stage of pressure reduction can prevent leakage of molten metallic lithium.

[0075] (Supplementary Note 4) The control method according to Supplementary Note 3, wherein the second pressure mechanism 5 includes an actuator.

[0076] According to this method, the actuator is operated in the first stage of depressurization. Therefore, after the abnormal state is resolved, pressurization by the actuator can be performed again, allowing the operation of the all-solid-state battery to continue. On the other hand, in the second stage of depressurization, the pressure applied by the first pressurizing mechanism 4 having an elastic body is reduced. Because an elastic body is used, the pressure can be reduced quickly in the second stage of depressurization. Therefore, leakage of metallic lithium is more reliably prevented.

[0077] (Supplementary Note 5) The control method according to Supplementary Note 3 or 4, further comprising the step of discharging the battery cell 3 when the temperature of the battery cell 3 is higher than the first temperature T1 and lower than the second temperature T2.

[0078] According to this method, the battery cell 3 is discharged before the second temperature T2 is reached, so that the metallic lithium at the negative electrode, which may leak, is reduced in advance, thereby more reliably preventing leakage of metallic lithium.

[0079] (Supplementary Note 6) The control method according to Supplementary Note 5 further comprises a step (S21) of detecting the charge amount of the battery cell, and when the charge amount of the battery cell 3 is less than a preset first charge amount A, the battery cell is not discharged even when the temperature of the battery cell 3 is higher than a first temperature T1 and lower than a second temperature T2.

[0080] According to this method, when the charge level is low and there is little possibility of leakage of metallic lithium, discharging is not performed. Therefore, a certain amount of charge is secured until the second temperature T2 is reached, and power can be used as needed.

[0081] (Supplementary Note 7) The control method according to Supplementary Note 6, wherein the battery cell 3 is configured so that metallic lithium is deposited on the negative electrode during charging and the metallic lithium is lost from the negative electrode during discharging, the all-solid-state battery further has an exterior body 15 that houses the battery cell 3, and the interior of the exterior body 15 is provided with a buffer space 19 that houses molten metallic lithium when the metallic lithium melts, and the first charge amount A is a charge amount such that the amount of metallic lithium deposited on the negative electrode is an amount that can be housed in the buffer space.

[0082] According to this method, when the temperature exceeds the first temperature T1, the battery cells 3 are discharged until the charge amount reaches an amount that allows the amount of metallic lithium that may leak to be accommodated in the buffer space. Therefore, even if the temperature subsequently reaches the melting temperature of metallic lithium, the molten metallic lithium can be accommodated in the buffer space, preventing leakage to the outside.

[0083] (Supplementary Note 8) The control method according to Supplementary Note 7, wherein the first charge amount A is a maximum value among charge amounts at which the amount of metallic lithium deposited on the negative electrode is an amount that can be accommodated in the buffer space.

[0084] According to this method, vibration resistance is maintained to the maximum extent possible as long as the amount of metallic lithium in the negative electrode is within the buffer space 19. Furthermore, electric power can be used up to the temperature at which metallic lithium melts (second temperature T2).

[0085] (Supplementary Note 9) The control method according to any one of Supplementary Notes 3 to 8, further comprising the step of determining that the battery cell is in an abnormally elevated temperature state when the battery cell temperature exceeds the first temperature T1.

[0086] This method makes it possible to notify the user of an abnormal state.

[0087] (Supplementary Note 10) The control method according to any one of Supplementary Notes 3 to 9, wherein the second temperature T2 is a value within a range of 150 to 210°C.

[0088] According to this method, the second temperature T2 is set to correspond to the melting temperature of metallic lithium, so that leakage of metallic lithium can be more reliably prevented.

Claims

A battery section including a battery cell in which metallic lithium is used as a negative electrode active material; a first pressurizing mechanism that pressurizes the battery unit; a second pressurizing mechanism that operates independently of the first pressurizing mechanism and pressurizes the battery unit; a first pressure reducing mechanism that reduces the pressure applied by the first pressure applying mechanism; a second pressure reducing mechanism that operates independently of the first pressure reducing mechanism and reduces the pressure applied by the second pressure applying mechanism; Equipped with The first pressure mechanism includes an elastic body. All-solid-state battery. 　 The all-solid-state battery according to claim 1 , The second pressure mechanism includes an actuator. All-solid-state battery. 　 A method for controlling the all-solid-state battery according to claim 1, detecting a temperature of the battery cell; When the temperature of the battery cell exceeds a preset first temperature T1, reducing the pressure applied by the second pressure reducing mechanism; When the temperature of the battery cell exceeds a preset second temperature T2 that is higher than the first temperature T2, reducing the pressure applied by the first pressure reducing mechanism; Equipped with Control methods.

4. The control method according to claim 3, The second pressure mechanism includes an actuator. Control methods.

4. The control method according to claim 3, The method further includes discharging the battery cell when the temperature of the battery cell is higher than the first temperature T1 and lower than the second temperature T2. Control methods.

6. The control method according to claim 5, Further, a step of detecting a charge amount of the battery cell is provided, When the charge amount of the battery cell is less than a preset first charge amount A, the battery cell is not discharged even if the temperature of the battery cell is higher than the first temperature T1 and lower than the second temperature T2. Control methods.

7. The control method according to claim 6, The battery cell is configured such that metallic lithium is deposited on a negative electrode during charging and metallic lithium is lost from the negative electrode during discharging; The all-solid-state battery further includes an exterior body that houses the battery cell, a buffer space is provided inside the exterior body to accommodate molten metallic lithium when the metallic lithium melts, The first charge amount A is a charge amount such that the amount of metallic lithium deposited on the negative electrode is an amount that can be accommodated in the buffer space. Control methods.

8. The control method according to claim 7, The first charge amount A is the maximum value among the charge amounts at which the amount of metallic lithium deposited on the negative electrode is an amount that can be accommodated in the buffer space. Control methods.

4. The control method according to claim 3, The method further includes a step of determining that the battery cell is in an abnormally elevated temperature state when the battery cell exceeds the first temperature T1. Control methods.

4. The control method according to claim 3, The second temperature T2 is a value in the range of 150 to 210 ° C. Control methods.

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