Battery pack

Abstract

To properly detect reaction unevenness in an all-solid battery.SOLUTION: A control device executes processing including a step (S102) of acquiring a detection value from each surface pressure sensor when it is charged (YES in S100), a step (S106) of specifying a corresponding pressurization part when an uneven reaction portion is determined (YES in S104), a step (S108) of outputting a pressurizing command, a step (S110) of determining whether pressurization is completed, and a step (S112) of outputting a pressurization cancelling command when pressurization is determined as complete (YES in S110).SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] This disclosure relates to the configuration of a battery pack.

Background Art

[0002] As a secondary battery, for example, an all-solid-state battery in which the battery is made completely solid using a solid electrolyte is known. Also, in an all-solid-state battery, since the adhesion between the positive electrode layer, the solid electrolyte layer, and the negative electrode layer, which are constituent members, affects various characteristics of the battery, a technique for appropriately detecting uneven reactions caused by this adhesion is required.

[0003] Japanese Patent Application Laid-Open No. 2020-161300 (Patent Document 1) discloses a technique for estimating the distribution state of lithium in a negative electrode active material layer using an estimation model.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, since uneven reactions in an all-solid-state battery occur with in-plane variations, it is required to appropriately detect the position of the in-plane uneven reactions. In Patent Document 1, since the in-plane uneven reactions are not considered, the position of the in-plane uneven reactions cannot be appropriately detected.

[0006] This disclosure has been made to solve the above-described problems, and an object thereof is to provide a battery pack that can appropriately detect uneven reactions in an all-solid-state battery.

Means for Solving the Problems

[0007] A battery pack relating to a certain aspect of this disclosure comprises a first solid-state battery, a second solid-state battery, a surface pressure sensor provided between the first solid-state battery and the second solid-state battery for detecting the distribution of in-plane pressure between the first solid-state battery and the second solid-state battery in a constrained state, and a control device that uses the detection results from the surface pressure sensor to detect locations where local pressure increases occur between the first solid-state battery and the second solid-state battery as locations where reaction unevenness occurs.

[0008] In this way, by using a surface pressure sensor, the in-plane pressure distribution between the first and second solid-state batteries can be detected, allowing for highly accurate detection of areas where localized pressure increases occur, thereby pinpointing the locations of reaction irregularities.

[0009] In one embodiment, the first and second solid-state batteries have the characteristic that, due to uneven reaction during charging and discharging of the battery pack, the thickness of the first and second solid-state batteries in the direction of arrangement increases compared to the initial state.

[0010] In this way, by using a surface pressure sensor to detect areas where localized pressure increases occur, it is possible to accurately detect the locations where reaction inconsistencies occur.

[0011] Furthermore, in one embodiment, the surface pressure sensor detects the distribution of in-plane pressure between the first solid-state battery and the second solid-state battery, and at the end sides closest to the first terminal of the first solid-state battery and the second terminal of the second solid-state battery, respectively.

[0012] In this way, the in-plane pressure distribution near the first and second terminals, where reaction unevenness is likely to occur, can be detected, and the location of reaction unevenness can be detected with high accuracy while suppressing cost increases. [Effects of the Invention]

[0013] According to this disclosure, it is possible to provide a battery pack that can appropriately detect reaction irregularities in all-solid-state batteries. [Brief explanation of the drawing]

[0014] [Figure 1] This figure shows an example of a battery pack configuration. [Figure 2] This figure shows an example of the configuration of an all-solid-state battery. [Figure 3] This figure shows an example of the configuration of the first pressurizing section and the second pressurizing section. [Figure 4] This flowchart shows an example of a process performed in a control device. [Figure 5] This figure shows an example of the configuration of the second pressurizing section in a modified example. [Figure 6] This figure shows an example of the configuration of a surface pressure sensor in a modified example. [Figure 7] This figure shows an example of the battery pack configuration in a modified example. [Modes for carrying out the invention]

[0015] The embodiments of this disclosure will be described in detail below with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and their descriptions will not be repeated.

[0016] Figure 1 shows an example of the configuration of battery pack 1. Battery pack 1 is installed in electric vehicles such as electric cars and plug-in hybrid vehicles, or other electric mobile devices. Battery pack 1 shown in Figure 1 may be charged while installed in the vehicle, or it may be charged while removed from the vehicle.

[0017] As shown in Figure 1, the battery pack 1 comprises a laminate 20, a first pressurizing unit 50, a second pressurizing unit 60, and a control device 100.

[0018] The laminate 20 includes a plurality of all-solid-state batteries 10a, 10b, 10c, 10d, 10e, 10f, 10g (hereinafter referred to as all-solid-state batteries 10a to 10g), and a plurality of surface pressure sensors 110a, 110b, 110c, 110d, 110e, 110f (hereinafter referred to as surface pressure sensors 110a to 110f).

[0019] The all-solid-state batteries 10a to 10g are batteries configured by solidifying all constituent members by setting a solid electrolyte as the electrolyte. Each of the all-solid-state batteries 10a to 10g has a rectangular shape. Each of the all-solid-state batteries 10a to 10g is stacked in the vertical direction of the paper surface of FIG. 1 with the positive electrode terminal and the negative electrode terminal protruding from the right side surface of the paper surface of FIG. 1. In the present embodiment, the laminate 20 will be described as being composed of seven all-solid-state batteries 10a to 10g, but the number is not limited to seven.

[0020] Also, although not particularly shown, each positive electrode terminal and each negative electrode terminal of the all-solid-state batteries 10a to 10g are connected to the adjacent all-solid-state batteries in a predetermined manner. The all-solid-state batteries 10a to 10g may be connected in series, for example, or may include a battery group with partial parallel connection.

[0021] The surface pressure sensor 110a has a sheet shape covering the contact surface with the all-solid-state battery 10a. The surface pressure sensor 110a is provided between the all-solid-state batteries 10a and 10b and detects the in-plane pressure (hereinafter referred to as in-plane pressure or surface pressure) between the all-solid-state batteries 10a and 10b.

[0022] The surface pressure sensor 110a includes multiple surface pressure detection points and transmits the surface pressure detection result at each detection point to the control device 100. The control device 100 acquires information from the surface pressure sensor 110a that combines the coordinates (detection position) of each detection point and the detected surface pressure value. Surface pressure sensors 110b to 110f are installed between solid-state batteries 10b and 10c, between solid-state batteries 10c and 10d, between solid-state batteries 10d and 10e, between solid-state batteries 10e and 10f, and between solid-state batteries 10f and 10g, respectively. The operation of surface pressure sensors 110b to 110f is the same as that of surface pressure sensor 110a, so a detailed explanation will not be repeated.

[0023] The first pressurizing section 50 and the second pressurizing section 60 are provided so as to sandwich the laminated body 20 from the top and bottom directions in the plane of Figure 1.

[0024] The first pressurizing section 50 applies restraining pressure in the downward direction of the paper in Figure 1. The first pressurizing section 50 is fixed, for example, in the position shown in Figure 1, and applies restraining pressure to the laminate 20 by having a member that can expand and contract in the downward direction of the paper in Figure 1.

[0025] The second pressurizing section 60 applies a restraining pressure in the upward direction of the paper in Figure 1. The second pressurizing section 60 is fixed in the position shown in Figure 1, for example, and applies restraining pressure to the laminate 20 by having a member that can expand and contract in the upward direction of the paper in Figure 1. The first pressurizing section 50 and the second pressurizing section 60 constitute a "restraining section" that applies restraining pressure to the laminate 20 in the stacking direction. The positions of the first pressurizing section 50 and the second pressurizing section 60 are fixed so that a constant restraining pressure is applied to the laminate 20 when they are not in operation.

[0026] The first pressurizing section 50 and the second pressurizing section 60 operate in accordance with control signals from the control device 100. The detailed configuration of the first pressurizing section 50 and the second pressurizing section 60 will be described later.

[0027] The control device 100 includes a CPU (Central Processing Unit) and memory. The memory includes various types of memory such as ROM (Read Only Memory) and RAM (Random Access Memory). Based on signals received from each of the surface pressure sensors 110a to 110f and information stored in memory (for example, maps and programs), the control device 100 controls the first pressurizing unit 50 and the second pressurizing unit 60 to reach a desired state. For example, when the battery pack 1 is being charged, the control device 100 increases or decreases the confinement pressure using the first pressurizing unit 50 and the second pressurizing unit 60 based on the detection results of each of the surface pressure sensors 110a to 110f.

[0028] Figure 2 shows an example of the configuration of an all-solid-state battery 10a. The all-solid-state battery 10a has a positive electrode current collector 11, a positive electrode layer 12, a solid electrolyte layer 13, a negative electrode layer 14, a negative electrode current collector 15, a positive electrode terminal 16, and a negative electrode terminal 17. All-solid-state batteries 10b to 10f have the same configuration as all-solid-state battery 10a. Therefore, a detailed explanation of them will not be repeated.

[0029] The solid electrolyte material included in the solid electrolyte layer 13 is not particularly limited as long as it is a material that can be used as a solid electrolyte in an all-solid-state battery. For example, the solid electrolyte material may be a sulfide-based amorphous solid electrolyte or an oxide-based amorphous solid electrolyte.

[0030] Furthermore, the active material included in the positive electrode layer 12 and the negative electrode layer 14 is not particularly limited and can be any material that can be used as an electrode active material for an all-solid-state battery. Examples of active materials include nickel-cobalt-lithium manganese oxide (NCM), nickel-cobalt-aluminum-lithium oxide (NCA), lithium cobalt oxide (LCO), lithium titanate (LTO), and lithium manganese oxide (LMO). Preferably, the all-solid-state battery has the characteristic that when reaction unevenness occurs during charging or discharging of the battery pack 1, the thickness of the all-solid-state battery including the positive electrode layer 12 and the negative electrode layer 14 increases at the location where the reaction unevenness occurs.

[0031] The positive electrode layer 12 and the negative electrode layer 14 may contain conductive additive particles. Examples of conductive additive particles include graphite and carbon black.

[0032] The materials for the positive electrode current collector 11 and the negative electrode current collector 15 are not particularly limited as long as they are conductive and have the respective functions of a positive electrode current collector and a negative electrode current collector. Examples include SUS (Steel Use Stainless), aluminum, copper, nickel, iron, titanium, and carbon. Furthermore, the shapes of the positive electrode current collector 11 and the negative electrode current collector 15 can be foil-shaped, plate-shaped, mesh-shaped, etc. A positive electrode terminal 16 is connected to the positive electrode current collector 11. A negative electrode terminal 17 is connected to the negative electrode current collector 15.

[0033] For the battery cases (not shown) that enclose each of the all-solid-state batteries 10a to 10g, known laminate films usable with all-solid-state batteries can be used. Examples of such laminate films include resin laminate films and films in which metal has been vapor-deposited onto a resin laminate film.

[0034] Although the case in which each of the all-solid-state batteries 10a to 10g has a rectangular (square) shape as shown in Figure 1 has been described as an example, any shape that allows a restraining pressure to be applied to the stacked body 20 formed by stacking the all-solid-state batteries 10a to 10g is acceptable. In addition to the square shape, they may have any desired shape such as cylindrical, button-shaped, coin-shaped, or flattened.

[0035] In the all-solid-state batteries 10a to 10g contained in the battery pack 1 having the above configuration, the adhesion between the positive electrode layer 12, the solid electrolyte layer 13, and the negative electrode layer 14 affects various characteristics of the battery. Therefore, since the reaction unevenness caused by this adhesion in the all-solid-state battery occurs with variation within the plane, it is necessary to appropriately detect the location of the reaction unevenness within the plane.

[0036] Therefore, in this embodiment, the system includes a surface pressure sensor that detects the distribution of in-plane pressure between a first solid-state battery and a second solid-state battery in a constrained state, and a control device that uses the detection results from the surface pressure sensor to detect locations where local pressure increases occur between the first solid-state battery and the second solid-state battery as locations where reaction irregularities occur.

[0037] In this way, by using surface pressure sensors 110a to 110f, the in-plane pressure distribution between the all-solid-state batteries 10a to 10f can be detected, allowing for highly accurate detection of locations where localized pressure increases occur, thereby pinpointing the locations of reaction irregularities.

[0038] The specific configurations of the first pressurizing section 50 and the second pressurizing section 60 will be described below with reference to Figure 3. Figure 3 is a diagram showing an example of the configuration of the first pressurizing section 50 and the second pressurizing section 60. For the sake of explanation, the laminated structure 20 of the battery pack 1 is omitted from Figure 3, and only the first pressurizing section 50 and the second pressurizing section 60 are shown.

[0039] The first pressurizing section 50 includes first partial pressurizing sections 50a, 50b, 50c, 50d, 50e, 50f, 50g, 50h, 50i, and 50j (hereinafter referred to as first partial pressurizing sections 50a to 50j). Each of the first partial pressurizing sections 50a to 50j has a rectangular contact surface with respect to one surface of the laminate 20 in the stacking direction. Each of the first partial pressurizing sections 50a to 50j is provided with an actuator (not shown) that is driven according to a control signal from the control device 100. By driving at least one of the actuators among the first partial pressurizing sections 50a to 50j, the contact surface with the laminate 20 is pressed, thereby partially increasing the restraining pressure.

[0040] The second pressurizing section 60 includes second partial pressurizing sections 60a, 60b, 60c, 60d, 60e, 60f, 60g, 60h, 60i, and 60j (hereinafter referred to as second partial pressurizing sections 60a to 60j). The second partial pressurizing sections 60a to 60j are provided at positions opposite to the first partial pressurizing sections 50a to 50j in the stacking direction. Each of the second partial pressurizing sections 60a to 60j has a rectangular contact surface with respect to the other surface of the laminate 20 in the stacking direction. Each of the second partial pressurizing sections 60a to 60j is provided with an actuator (not shown) that is driven according to a control signal from the control device 100. When at least one of the actuators in the second partial pressurizing sections 60a to 60j is driven, it presses against the contact surface with the laminate 20, thereby partially increasing the restraining pressure.

[0041] For example, if the first partial pressurization section 50a is selected as the control target, the control device 100 selects the second partial pressurization section 60a as the control target. In this way, the control device 100 selects the first partial pressurization sections 50a to 50j and the second partial pressurization sections 60a to 60j as control targets, for example, by associating them with each other.

[0042] For example, when the control device 100 selects the first partial pressurizing section 50a and the second partial pressurizing section 60a as the control targets, it applies a partial restraining pressure to the laminated body 20 by using the first partial pressurizing section 50a and the second partial pressurizing section 60a to sandwich the contact surface between the first partial pressurizing section 50a and the laminated body 20 and the contact surface between the second partial pressurizing section 60a and the laminated body 20.

[0043] The same applies when the control device 100 controls the first partial pressurization section 50b to 50j and the second partial pressurization section 60b to 60j, respectively. Therefore, a detailed explanation will not be repeated.

[0044] When one of the first partial pressurizing sections 50a to 50j operates to press against the laminate 20, and the corresponding second partial pressurizing section among the second partial pressurizing sections 60a to 60j operates to press against the laminate 20, the restraining pressure between the contact surface of the first partial pressurizing section and the contact surface of the second partial pressurizing section of the laminate 20 is partially increased.

[0045] The following describes an example of the processes performed by the control device 100 with reference to Figure 4. Figure 4 is a flowchart showing an example of the processes performed by the control device 100. The series of processes shown in this flowchart are repeatedly executed by the control device 100 at predetermined intervals.

[0046] In step 100 (hereinafter referred to as S), the control device 100 determines whether or not the battery pack 1 is being charged. The control device 100 may determine that the battery pack 1 is being charged if a charging current is detected in the battery pack 1 using, for example, a current sensor (not shown). If it is determined that the battery pack 1 is being charged (YES in S100), the process moves to S102.

[0047] In S102, the control device 100 acquires detection values ​​from each of the surface pressure sensors 110a to 110f. The subsequent processing is then moved to S104.

[0048] In S104, the control device 100 determines whether or not there are areas of uneven reaction. Specifically, the control device 100 determines that there are areas of uneven reaction if there is a spot among multiple detection points where the surface pressure is higher than the others. For example, the control device 100 calculates the average value of the surface pressure at multiple detection points. The control device 100 determines that there are areas of uneven reaction if there is a detection point where the value is higher than the calculated average value of the detected surface pressures at multiple detection points plus a predetermined value. If it is determined that there are areas of uneven reaction (YES in S104), the process moves to S106.

[0049] In S106, the control device 100 identifies the corresponding partial pressurization section. The control device identifies a first partial pressurization section and a second partial pressurization section as corresponding partial pressurization sections, which are located in a positional relationship that encloses the detection point identified as the reaction unevenness area. The control device 100 may, for example, pre-store a map showing the relationship between the coordinates of the detection point and the partial pressurization section, and identify the corresponding partial pressurization section from the coordinates of the detection point corresponding to the reaction unevenness area and the said map. The subsequent processing is moved to S108.

[0050] In S108, the control device 100 outputs a pressurizing command. The control device 100 sets the identified partial pressurizing section as the control target and outputs a pressurizing command to the set control target. For example, the control device 100 may generate a pressurizing command so that the confinement pressure increases by a predetermined value, or it may generate a pressurizing command so that the confinement pressure increases by an amount corresponding to the difference between the detected surface pressure value at the detection point and the average value of the detected values ​​at each detection point. The process then moves to S110.

[0051] In S110, the control device 100 determines whether or not pressurization is complete. For example, the control device 100 determines that pressurization is complete when a predetermined time has elapsed since pressurization began. The process then proceeds to S112.

[0052] In S112, the control device 100 outputs a pressure release command. The control device 100 outputs a pressure release command to the controlled object that is set to stop pressurizing by the partial pressurizing unit. The process is then terminated.

[0053] The operation of the control device 100 of the battery pack 1 according to this embodiment, based on the structure and flowchart described above, will be explained.

[0054] For example, consider a case where the battery pack 1 mounted on the vehicle is being charged using an external power source. Furthermore, consider a case where, for example, uneven reaction occurs in the area corresponding to the first partial pressurization section 50a and the second partial pressurization section 60a of the all-solid-state battery 10b, which is one of the all-solid-state batteries 10a to 10g constituting the stacked structure 20.

[0055] If it is determined that the battery pack 1 is charging (YES in S100), the control device 100 acquires detection values ​​from each of the surface pressure sensors 110a to 110f (S102). Using the acquired detection values ​​from the surface pressure sensors 110a to 110f, the average value of the surface pressure at each of the multiple detection points is calculated. If it is determined that the detection value of the surface pressure at the detection point of surface pressure sensor 110a among the multiple detection points is greater than the value obtained by adding a predetermined value to the average value, it is determined that there is a reaction unevenness (YES in S104), and the partial pressurization area corresponding to the reaction unevenness is identified (S106).

[0056] Based on the coordinates of the surface pressure sensor 110a where a reaction unevenness is determined to exist, the first partial pressurizing section 50a and the second partial pressurizing section 60a are identified as partial pressurizing sections corresponding to the reaction unevenness.

[0057] Then, the identified partial pressurization sections, namely the first partial pressurization section 50a and the second partial pressurization section 60a, are set as control targets, and a pressurization command is output to the set control targets (S108).

[0058] In accordance with the pressurization command, actuators in the first partial pressurization section 50a and the second partial pressurization section 60a are driven, causing the first partial pressurization section 50a to pressurize the contact surface with the laminate 20, and the second partial pressurization section 60a to pressurize the contact surface with the laminate 20, thereby locally increasing the constraining pressure at the reaction unevenness locations of the laminate 20. As a result, the adhesion between the solid electrolyte layer and the positive electrode layer or negative electrode layer increases, resistance decreases, and the occurrence of reaction unevenness is eliminated.

[0059] Once a predetermined time has elapsed and pressurization is complete (NO in S110), a pressurization release command is output (S112), causing the first partial pressurization section 50a and the second partial pressurization section 60a to return to their initial state before pressurization.

[0060] As described above, with the battery pack 1 according to this embodiment, by using surface pressure sensors 110a to 110f, the distribution of in-plane pressure between the all-solid-state batteries 10a to 10f can be detected. Therefore, by detecting the locations where localized pressure increases occur, the locations where reaction irregularities occur can be detected with high accuracy. Thus, a battery pack that can appropriately detect reaction irregularities in all-solid-state batteries can be provided.

[0061] Furthermore, by applying pressure to a portion of the contact surface, the restraining pressure at the location where reaction unevenness occurs is increased, thereby improving the adhesion of the constituent members at the location where reaction unevenness occurs in the laminate 20, and eliminating the reaction unevenness. In addition, it is possible to suppress unnecessary restraining pressure from acting on parts other than the location where the unevenness occurs.

[0062] If multiple areas with uneven reaction are detected, the corresponding partial pressurization units are set as control targets, and pressurization commands are output to each set control target.

[0063] The following describes variations.

[0064] In the above-described embodiment, the case of determining whether or not there are areas of uneven reaction during charging was explained as an example, but it is also possible to determine whether or not there are areas of uneven reaction during discharge.

[0065] Furthermore, in the above-described embodiment, it was explained that pressurization is determined to be complete and a release command is output when a predetermined time has elapsed since the output of the pressurization command. However, for example, pressurization may be determined to be complete and a release command output when the resistance value of the all-solid-state battery, including the reaction unevenness area, falls below a threshold value after the output of the pressurization command.

[0066] Furthermore, in the above-described embodiment, an example was explained in which reaction unevenness within the all-solid-state batteries 10a to 10g is eliminated by applying pressure using at least one of the first partial pressurization sections 50a to 50j and the second partial pressurization sections 60a to 60j. However, in order to promote the elimination of reaction unevenness, for example, in addition to pressurization, heating control may be performed to heat the laminate 20 or the all-solid-state batteries 10a to 10g where reaction unevenness is occurring, or voltage control may be performed to change the voltage. As for heating control, for example, it may be a control to heat the all-solid-state batteries 10a to 10g using a heating device such as a heater, a control to reduce the degree of cooling by a cooling device (not shown) provided in the battery pack 1, or a control to stop cooling by the cooling device. As for voltage control, during charging, it may be a control to increase the voltage of all-solid-state batteries where reaction unevenness is not occurring, or a control to stop charging. Also, as for voltage control, during discharge, it may be a control to decrease the voltage of all-solid-state batteries where reaction unevenness is not occurring, or a control to stop discharge.

[0067] Furthermore, in the above-described embodiment, the case in which each of the first partial pressurizing sections 50a to 50j and the second partial pressurizing sections 60a to 60j has a contact surface of the same area with respect to the laminate 20 was described as an example. However, each of the first partial pressurizing sections 50a to 50j and the second partial pressurizing sections 60a to 60j may have a contact surface of different area or shape with respect to the laminate 20.

[0068] For example, the multiple partial pressurizing sections may be arranged to pressurize a portion of the contact surface with the laminate 20 that is closer to the terminals (positive and negative terminals) of the all-solid-state batteries 10a to 10g. Alternatively, the multiple partial pressurizing sections may be concentrated closer to the terminals.

[0069] Figure 5 shows an example of the configuration of the second pressurization section 160 in a modified example. For ease of explanation, Figure 5 omits the display of the laminated body 20 and the first pressurization section of the battery pack 1, and only the second pressurization section 160 is shown.

[0070] As shown in Figure 5, the second pressurizing section 160 includes second partial pressurizing sections 160a, 160b, 160c, 160d, 160e, 160f, 160g, 160h, 160i, and 160j (hereinafter referred to as second partial pressurizing sections 160a to 160j).

[0071] The second partial pressurizing section 160a has a rectangular contact surface with the laminate 20 and has the largest contact surface area with the laminate 20 compared to the second partial pressurizing sections 160b to 160j. On the other hand, each of the second partial pressurizing sections 160b to 160j has a rectangular contact surface with the laminate 20 and has approximately the same area.

[0072] The first pressurizing section has a plurality of first partial pressurizing sections that are the same shape as the second pressurizing section 160. The plurality of first partial pressurizing sections are positioned opposite the second partial pressurizing sections 160a to 160j.

[0073] In this way, the constraining pressure can be partially increased in the region near the terminals, where reaction unevenness is likely to occur in all-solid-state batteries. Therefore, the adhesion of the components in the region near the terminals can be improved. Furthermore, it is possible to suppress unnecessary constraining pressure from acting on parts other than the affected area. Note that the second partial pressurizing section 160a and the corresponding first partial pressurizing section may be configured without a mechanism that enables pressurization. In this way, the partial pressurizing section can be positioned to pressurize a portion of the contact surface closer to the terminals.

[0074] In this case, the shape of the sheet containing the detection point of the surface pressure sensor can be made to cover the area where the laminate 20 and the partially pressurized part come into contact, rather than covering the surface in the stacking direction of the all-solid-state battery. Figure 6 shows an example of the configuration of the surface pressure sensor in a modified example. By arranging the partially pressurized part in an area close to the terminals and making it a shape that covers the contact surface between the partially pressurized part and the laminate 20, as shown by the solid line in Figure 6, the shape of the sheet containing the detection point of the surface pressure sensor can be made smaller than when the entire surface in the stacking direction of the all-solid-state battery, including the dashed line in Figure 6, is covered.

[0075] In this way, by arranging the surface pressure sensors 110a to 110f between the solid-state batteries 10a to 10g and to detect the distribution of in-plane pressure at the end sides close to the terminals of each solid-state battery 10a to 10g within the plane, the distribution of in-plane pressure at the end sides close to the terminals, where reaction irregularities are likely to occur, can be detected, and the location of reaction irregularities can be detected with high accuracy while suppressing cost increases.

[0076] Furthermore, in the above-described embodiment, a configuration was explained as an example in which the laminate 20 is sandwiched between the first pressurizing section 50 and the second pressurizing section 60, thereby applying a restraining pressure to the entire laminate 20 in the stacking direction of the laminate 20. However, the invention is not particularly limited to such a configuration.

[0077] For example, in addition to the first pressurizing section 50 and the second pressurizing section 60, a third pressurizing section may be included that partially increases the restraining pressure in the section containing the generation region among the multiple sections obtained by dividing the laminate 20 in the longitudinal direction.

[0078] Figure 7 shows an example of the configuration of the battery pack 1 in a modified example. As shown in Figure 7, the battery pack 1 includes a third pressurizing section 90 in place of the surface pressure sensor 110c in the configuration described using Figure 1. The third pressurizing section 90 is provided so as to sandwich the first stack 22, which contains three solid-state batteries 10a to 10c, between itself and the first pressurizing section 50. Furthermore, the third pressurizing section 90 is provided so as to sandwich the second stack 24, which contains the remaining solid-state batteries 10d to 10g, between itself and the second pressurizing section 60. The third pressurizing section 90 includes a plurality of third partial pressurizing sections (not shown). The third pressurizing section is configured to be able to pressurize both the first stack 22 and the second stack 24. Each of the plurality of third partial pressurizing sections operates in accordance with a control signal from the control device 100 and is provided at a position corresponding to the partial pressurizing section of the first pressurizing section 50 and the pressurizing section of the second pressurizing section 60, respectively. The third pressurizing section 90 may be provided so as to be fastened to, for example, a base that secures the battery pack 1, or its position may be restricted by fixing the first pressurizing section 50 and the second pressurizing section 60 in the same way as the adjacent first laminate 22 and second laminate 24.

[0079] The control device 100 identifies areas where unevenness occurs using the detection results from multiple detection points using surface pressure sensors 110a, 110b, 110d, 110e, and 110f, and operates the partial pressurizing unit corresponding to the identified area.

[0080] For example, if the control device 100 determines that there are areas of uneven reaction within the first laminate 22, it operates the partial pressurizing units in the first pressurizing unit 50 and the third pressurizing unit 90 corresponding to the locations where the unevenness occurs, thereby partially increasing the restraining pressure.

[0081] Furthermore, if the control device 100 determines, for example, that there are areas of uneven reaction within the second laminate 24, it operates the partial pressurizing units in the third pressurizing unit 90 and the second pressurizing unit 60 corresponding to the locations where the unevenness occurs, thereby partially increasing the restraining pressure.

[0082] This method allows for concentrated increases in the confinement pressure in areas where reaction inconsistencies occur, thereby improving adhesion in those regions and preventing unnecessary confinement pressure from being applied to other parts.

[0083] Furthermore, the above-mentioned modifications may be implemented by combining all or part of them as appropriate.

[0084] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the claims rather than by the foregoing description, and all modifications within the meaning and scope equivalent to the claims are intended to be included. [Explanation of Symbols]

[0085] 1 Battery pack, 10a~10g all-solid-state battery, 11 Positive electrode current collector, 12 Positive electrode layer, 13 Solid electrolyte layer, 14 Negative electrode layer, 15 Negative electrode current collector, 20 Laminate, 22 First laminate, 24 Second laminate, 50 First pressurized section, 50a~50j First partial pressurized section, 60, 160 Second pressurized section, 60a~60j, 160a~160j Second partial pressurized section, 90 Third pressurized section, 100 Control device, 110a~110f Surface pressure sensor.

Claims

1. The first all-solid-state battery, The second all-solid-state battery, A surface pressure sensor is provided between the first solid-state battery and the second solid-state battery in a constrained state to detect the distribution of in-plane pressure between the first solid-state battery and the second solid-state battery, A battery pack comprising a control device that uses the detection results from the surface pressure sensor to detect locations where localized pressure increases occur between the first solid-state battery and the second solid-state battery as locations where reaction unevenness occurs.

2. The battery pack according to claim 1, wherein the first solid-state battery and the second solid-state battery have the characteristic that the thickness of the first solid-state battery and the second solid-state battery in the arrangement direction increases from the initial state due to the occurrence of reaction unevenness during charging and discharging of the battery pack.

3. The battery pack according to claim 1, wherein the surface pressure sensor is located between the first solid-state battery and the second solid-state battery, and detects the distribution of in-plane pressure at the end sides closest to the first terminal of the first solid-state battery and the second terminal of the second solid-state battery, respectively.

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