Ion Acceptable State Estimation Device for All-Solid-State Battery

Abstract

To provide an ion distribution state estimation device for an all-solid-state battery that can estimate with high accuracy the state in which ions can be accepted in a negative electrode active material layer.SOLUTION: In an ion distribution state estimation device for an all-solid-state battery, a negative electrode active material layer 25 of a negative electrode includes a plurality of layer components 30 arranged on a straight line L, and each of the layer component is divided into a plurality of parts 31 and 32 according to the position in the direction connecting the center of the layer component and the outer peripheral edge, and the ion distribution state estimation device includes a resistance value estimating unit that estimates the resistance value when ions move between adjacent parts from the outer peripheral edge side to the center side, taking into consideration the elapsed time from a predetermined time of the all-solid-state battery 20, and an acceptance amount estimation unit that estimates the amount of ions that can be accepted by the part 31 located on the outermost edge side of each layer component while taking into account the resistance value.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to an apparatus for estimating the ion distribution state of an all-solid-state battery.

Background Art

[0002] The following Patent Document 1 discloses an all-solid-state secondary battery system that estimates the distribution state of lithium ions in the negative electrode active material of the negative electrode of an all-solid-state secondary battery and controls the maximum charging rate of the all-solid-state secondary battery based on the estimated distribution state.

Prior Art Document

Patent Document

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] There is room for improvement in the estimation accuracy of the ion-acceptable state in the negative electrode active material layer in the invention of Patent Document 1 above.

[0005] In consideration of the above facts, the present invention aims to obtain an all-solid-state battery capable of estimating the ion-acceptable state in the negative electrode active material layer with high accuracy. Ion Acceptable State Estimation Device

Means for Solving the Problems

[0006] ... of the negative electrode of an all-solid-state battery in which a positive electrode, a solid electrolyte layer, and a negative electrode are arranged linearly in this order Ion Acceptable State Estimation Device is An ion acceptable state estimation device for estimating the ion-acceptable state in a negative electrode active material layer the... of the negative electrode The aboveThe negative electrode active material layer includes a plurality of layer components arranged on the straight line, each of the layer components is divided into a plurality of parts according to the position in the direction connecting the center and the outer peripheral edge of the layer component, and the resistance value when ions move from the outer peripheral edge side to the center side between the adjacent parts is estimated while considering the elapsed time from a predetermined time of the all-solid-state battery. A capacitance estimation unit that estimates the amount of ions that can be received by the part located on the outermost peripheral edge side of each layer component while considering the resistance value. is provided, and when the capacitance estimation unit estimates that the ions enter the surface layer portion, which is the portion on the outermost peripheral edge side of the target layer component, which is the predetermined layer component, the internal resistance value when the ions move from the surface layer portion of the target layer component to the deep layer portion, which is the portion on the center side of the target layer component from the surface layer portion of the target layer component, is greater than the surface resistance value when the ions move from the target layer component to the surface layer portion of the adjacent layer component of the target layer component, it is estimated that the ions enter the surface layer portion of the adjacent layer component, and when the internal resistance value is less than or equal to the surface resistance value, it is estimated that the ions enter the deep layer portion of the target layer component 。

[0007] The all-solid-state battery according to claim 1 Ion Acceptable State Estimation Device estimates the resistance value when ions move from the outer peripheral edge side to the center side between adjacent parts of each layer component of the negative electrode active material layer while considering the elapsed time from a predetermined time of the all-solid-state battery. Furthermore Ion Acceptable State Estimation Device estimates the amount of ions that can be received by the part located on the outermost peripheral edge side of each layer component of the negative electrode active material layer while considering the estimated resistance value. Therefore, the all-solid-state battery according to claim 1 Ion Acceptable State Estimation Device can estimate the ion-receiving state in the negative electrode active material layer with higher accuracy compared to the case where the resistance value when ions move from the outer peripheral edge side to the center side between adjacent parts of each layer component of the negative electrode active material layer is not estimated.

[0008] The all-solid-state battery according to claim 2 Ion Acceptable State Estimation Device is, in claim 1, each of the layer components has a surface layer part that is the part located on the outermost peripheral edge side and a deep layer part that is located on the inner peripheral side of the surface layer part.

[0009] The all-solid-state battery according to claim 2 Ion Acceptable State Estimation Device can more easily estimate the amount of ions that can be received by the part located on the outermost peripheral edge side of each layer component of the negative electrode active material layer compared to the case where each layer component of the negative electrode active material layer is divided into three or more parts.

[0010] The all-solid-state battery according to claim 3 Ion Acceptable State Estimation Device is, in claim 1 or claim 2, the negative electrode active material layer contains lithium titanate (LTO).

[0011] For the all-solid-state battery according to claim 3 Ion Acceptable State Estimation Device it is possible to estimate with higher accuracy the ion-acceptable state in the negative electrode active material layer.

Advantages of the Invention

[0012] As described above, the ion distribution state estimation device for the all-solid-state battery according to the present invention has an excellent effect of being able to estimate with high accuracy the ion-acceptable state in the negative electrode active material layer.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Modes for Carrying Out the Invention

[0014] Hereinafter, an embodiment of the all-solid-state battery according to the present invention Ion Acceptable State Estimation Device will be described with reference to the drawings.

[0015] The vehicle 10 shown in FIG. 1 includes an all-solid-state battery 20, a battery control ECU 40 (hereinafter referred to as ECU 40), and a drive source 50.

[0016] The all-solid-state battery 20 is a lithium-ion secondary battery and includes a positive electrode current collector layer 21, a positive electrode active material layer 22, a solid electrolyte layer 24, a negative electrode active material layer 25, and a negative electrode current collector layer 26. The positive electrode current collector layer 21, the positive electrode active material layer 22, the solid electrolyte layer 24, the negative electrode active material layer 25, and the negative electrode current collector layer 26 are arranged along a single straight line L in this order. Further, the positive electrode current collector layer 21 and the positive electrode active material layer 22 are components of the positive electrode 23, and the negative electrode active material layer 25 and the negative electrode current collector layer 26 are components of the negative electrode 27. The positive electrode 23, the solid electrolyte layer 24, and the negative electrode 27 form a single series circuit.

[0017] The constituent material of the positive electrode current collector layer 21 is, for example, SUS, aluminum, copper, nickel, iron, titanium, or carbon, but is not limited thereto.

[0018] The positive electrode active material layer 22 contains at least a positive electrode active material. The material of the positive electrode active material is, for example, lithium cobalt oxide (LiCoO2), lithium nickel oxide (LiNiO2), or lithium manganate (LiMn2O4), but is not limited thereto.

[0019] The solid electrolyte layer 24 contains at least a solid electrolyte. The material of the solid electrolyte is not particularly limited, and a material that can be used as the solid electrolyte of the all-solid-state battery 20 can be used.

[0020] As shown in FIG. 2, the negative electrode active material layer 25 has N layer components 30 arranged along the straight line L. N is a natural number of 2 or more. Further, each layer component 30 has two sites with different positions in the direction connecting the center and the outer peripheral edge of the layer component 30. That is, each layer component 30 has a surface layer portion 31 that is a site on the outer peripheral edge side of the layer component 30 and a deep layer portion 32 located on the inner peripheral side of the surface layer portion 31 (see the dotted line in FIG. 2). Note that the boundary between the surface layer portion 31 and the deep layer portion 32 does not actually exist.

[0021] The negative electrode active material layer 25 contains lithium titanate (LTO), a binder that binds LTO particles to each other, and a conductive aid.

[0022] The material used for the negative electrode current collector layer 26 is, for example, the material used for the positive electrode current collector layer 21.

[0023] The vehicle 10 is equipped with an electric motor as a drive source 50. When a start button (not shown) provided on the vehicle 10 is turned ON, the electric motor can receive the electric power discharged from the all-solid-state battery 20. The electric motor that has received the electric power operates to generate a driving force.

[0024] The vehicle 10 has an ECU 40 as a hardware configuration. The ECU 40 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), a storage, an in-vehicle communication I / F, and an input / output I / F. The CPU, ROM, RAM, storage, in-vehicle communication I / F, and input / output I / F are communicably connected to each other via an internal bus. Further, the ECU 40 can acquire information regarding the date and time from a timer (not shown).

[0025] The CPU is a central processing unit that executes various programs and controls each part. The CPU reads a program from the ROM or the storage and executes the program using the RAM as a work area. The CPU performs control of each component and various arithmetic processes according to the program recorded in the ROM or the storage.

[0026] The ROM stores various programs and various data. The RAM temporarily stores a program or data as a work area. The storage is composed of a storage device such as an HDD (Hard Disk Drive) or an SSD (Solid State Drive) and stores various programs and various data.

[0027] The in-vehicle communication I / F is an interface for the ECU 40 to communicate with other devices.

[0028] The input / output I / F is an interface for communicating with each device mounted on the vehicle 10. The input / output I / F is connected to, for example, the all-solid-state battery 20.

[0029] FIG. 3 shows an example of the functional configuration of the ECU 40 in a block diagram. The ECU 40 includes, as functional components, a resistance value estimation unit 401, a charge / discharge amount calculation unit 402, a charge / discharge control unit 403, and a SOC acquisition unit 404. The resistance value estimation unit 401, the charge / discharge amount calculation unit 402, the charge / discharge control unit 403, and the SOC acquisition unit 404 are realized by the CPU reading and executing a program stored in the ROM.

[0030] The resistance value estimation unit 401 calculates the electrical resistance value of the negative electrode active material layer 25 (layer component 30) (hereinafter, resistance value R (unit: mΩ)). The resistance value R is the sum of the SE resistance value X, the surface layer resistance value Y, and the internal resistance value Z, which will be described later. As described above, the negative electrode active material layer 25 includes N layer components 30. When the all-solid-state battery 20 is charged with electric power, lithium ions (hereinafter, Li ions) in the positive electrode 23 (positive electrode active material layer 22) move to the negative electrode active material layer 25 through the solid electrolyte layer 24. The Li ions that have passed through the solid electrolyte layer 24 move to the negative electrode active material layer 25 through the first layer component 30 adjacent to the solid electrolyte layer 24. Further, the Li ions that have moved to the negative electrode active material layer 25 move from the first layer component 30 side to the Nth layer component 30 side. Here, the resistance value when the Li ions move through the solid electrolyte layer 24 is referred to as the SE resistance value X (unit: mΩ). The SE resistance value X is a fixed value. In the following description, the SE resistance value X may be abbreviated as "X".

[0031] Furthermore, the resistance value when Li ions move inside the surface layer portion 31 of each layer component 30 is referred to as the surface layer resistance value Y (unit: mΩ). The surface layer resistance value Y of each layer component 30 is the same fixed value. In the following description, the surface layer resistance value Y may be abbreviated as "Y".

[0032] When Li ions move from the surface layer portion 31 to the deep layer portion 32 of each layer component 30, the resistance value is referred to as the internal resistance value Z (unit: mΩ). In the following description, the internal resistance value Z may be abbreviated as "Z". The internal resistance values Z of each layer component 30 are the same. When Li ions move from the solid electrolyte layer 24 or an adjacent layer component 30 to any one layer component 30, the Li ions first enter the surface layer portion 31. That is, when Li ions move to any one layer component 30, the Li ions are first intercalated by the surface layer portion 31. When new Li ions attempt to enter the surface layer portion 31 in a state where the surface layer portion 31 can no longer intercalate new Li ions, the Li ions on the surface layer portion 31 move to the deep layer portion 32, and the Li ions are intercalated by the deep layer portion 32. Further, the new Li ions are intercalated by the region (empty region) where the Li ions on the surface layer portion 31 have moved to the deep layer portion 32.

[0033] In FIG. 2, the resistance values R of the surface layer portion 31 and the deep layer portion 32 of each layer component 30 are described. Here, the surface layer portion 31 of the Nth layer component 30 is indicated by <2N - 1>, and the deep layer portion 32 of the Nth layer component 30 is indicated by <2N>. Therefore, for example, the surface layer portion 31 of the first layer component 30 is <1>, and the deep layer portion 32 of the first layer component 30 is <2>.

[0034] For example, the resistance when Li ions enter the surface layer portion 31 of the first layer component 30 from the solid electrolyte layer 24 is 0 (zero) mΩ, and the resistance when Li ions enter the surface layer portion 31 of the second layer component 30 from the surface layer portion 31 of the first layer component 30 is Y mΩ. Therefore, the average value of the surface resistance value Y when Li ions pass through the surface layer portion 31 of one layer component 30 is Y / 2. Accordingly, the resistance value R when Li ions pass through the solid electrolyte layer 24 and <1> is X + Y / 2, and the resistance value R when Li ions pass through the solid electrolyte layer 24, <1>, and <2> is X + Y / 2 + Z. Further, after the Li ions pass through the solid electrolyte layer 24, the resistance value R when passing through <2N - 1> is X + (N - 1)Y + Y / 2, and the resistance value R when passing through <2N> is X + (N - 1)Y + Y / 2 + Z.

[0035] As shown in FIG. 4, the internal resistance value Z of the layer component 30 increases with the passage of time. That is, the inventor obtained the relationship between the average staying SOC (State of Charge), the absolute temperature (average staying temperature), the reference elapsed time which is the elapsed time from a predetermined time of the all-solid-state battery 20, and the internal resistance value Z obtained every minute through bench experiments, and performed an Arrhenius plot using this relationship to obtain the map (graph) 55 shown in FIG. 4. This predetermined time is, for example, the time when a predetermined time has elapsed from the manufacturing time (completion time) of the all-solid-state battery 20. The map 55 is recorded in the ROM. The vertical axis of this graph 55 is the value obtained by dividing the change amount of the internal resistance value Z by the square root of the reference elapsed time, and the horizontal axis is 1000 / T (T: absolute temperature). Although FIG. 4 shows only the cases where the SOC is 100%, 50%, and 0%, this map also includes data for various other values of the SOC.

[0036] "The first use" in Table 60 of FIG. 5 represents the period from the shipping time when the vehicle 10 is shipped from the manufacturing factory until the start button is first turned ON and then turned OFF.

[0037] In the first use, "history (1)" is obtained in the time period from the manufacturing time of the vehicle 10 until the start button is first turned ON. This history (1) includes the absolute temperature, the average staying SOC, and the elapsed time of the all-solid-state battery 20 in this time period. The absolute temperature is obtained every minute by a temperature sensor (not shown) provided in the all-solid-state battery 20 and connected to the battery control ECU 40. The average staying SOC is obtained every minute by the SOC acquisition unit 404. The elapsed time is obtained every minute by the above timer. The history (1) is recorded in the storage.

[0038] Next, in the first use, in the time period from when the start button is turned ON until it is turned OFF, the internal resistance value Z is obtained and "history (2)" is obtained. The latest obtained internal resistance value Z is recorded in the storage.

[0039] The internal resistance value Z at the first use is calculated by the resistance value estimation unit 401 based on the initial manufacturing value Z0 of the internal resistance value Z (see FIG. 6), the absolute temperature, the average staying SOC, the elapsed time of the history (1), and the map 55. Specifically, the value obtained by applying the latest absolute temperature and the latest average staying SOC of the history (1) to the map 55 is divided by the square root of the elapsed time from the shipment time to obtain the change amount ΔZ1-1 of the internal resistance value Z. Further, the internal resistance value Z1-1 (see FIG. 6) which is the internal resistance value Z at the time when the start button is turned ON = the initial manufacturing value Z0 + the change amount ΔZ1-1 is obtained.

[0040] Furthermore, when the time from when the start button is turned ON until it is turned OFF is 1 hour or more, when 1 hour has elapsed since the start button was turned ON, the resistance value estimation unit 401 applies the latest absolute temperature and the latest average staying SOC of the history (2) obtained during this 1 hour to the map 55, and divides the value by the square root of the elapsed time (1 hour) to obtain the change amount ΔZ1-2 of the internal resistance value Z. Further, the internal resistance value Z1-2 (see FIG. 6) which is the internal resistance value Z at this time = the internal resistance value Z1-1 + the change amount ΔZ1-2 is obtained.

[0041] When the start button is turned OFF after being turned ON at the first use, the vehicle 10 becomes inoperable. However, the acquisition of the history (2) continues until the start button is turned ON next. The history (2) is recorded in the storage.

[0042] Next, at the second use, the internal resistance value Z is acquired and the history (3) is acquired during the time period from when the start button is turned ON until it is turned OFF.

[0043] The internal resistance value Z for the second use is calculated by the resistance value estimation unit 401 based on the latest value of the internal resistance value Z for the first use recorded in the storage (for example, the internal resistance value Z1-2), the absolute temperature, the average staying SOC, the elapsed time of the history (2), and the map 55. Specifically, the value obtained by applying the latest absolute temperature and the latest average staying SOC of the history (2) to the map 55 is divided by the square root of the elapsed time from the OFF operation time of the start button for the first use to the ON operation time of the start button for the second use, thereby obtaining the change amount ΔZ2-1 of the internal resistance value Z. Further, the internal resistance value Z2-1 (see FIG. 6) which is the internal resistance value Z at the time when the start button is turned ON = the latest value of the internal resistance value Z for the first use recorded in the storage (for example, the internal resistance value Z1-2) + the change amount ΔZ2-1 is obtained.

[0044] Furthermore, when the time from when the start button is turned ON to when it is turned OFF is 1 hour or more, when 1 hour has elapsed since the start button was turned ON, the resistance value estimation unit 401 divides the value obtained by applying the latest absolute temperature and the latest average staying SOC of the history (3) acquired during this 1 hour to the map 55 by the square root of the elapsed time (1 hour), thereby obtaining the change amount ΔZ2-2 of the internal resistance value Z. Further, the internal resistance value Z2-2 (see FIG. 6) which is the internal resistance value Z at this time = the internal resistance value Z2-1 + the change amount ΔZ2-2 is obtained.

[0045] Hereinafter, the internal resistance values Z for the third use, the fourth use, ··· are similarly obtained.

[0046] The charge / discharge amount calculation unit 402 (CPU) estimates the intercalation state of Li ions in each layer component 30 of the negative electrode active material layer 25 based on the flowchart shown in FIG. 7.

[0047] When charge control of the all-solid-state battery 20 is executed, the CPU estimates in step S10 (hereinafter, the characters of the steps are omitted) that Li ions enter the surface layer portion 31 (<1>) of the first layer component 30.

[0048] Subsequently, at S11, the CPU determines whether the internal resistance value Z is greater than the surface resistance value Y. If it determines Yes, the CPU proceeds to S12 and estimates that the Li ions enter the surface layer portion 31 (<3>) of the second layer component 30. On the other hand, if it determines No, the CPU proceeds to S13 and estimates that the Li ions enter the deep layer portion 32 (<2>) of the first layer component 30. Further, the CPU proceeds to S14 and estimates that the Li ions enter in the order of <3> → <4> → <5> → <6> → <7> → <8> → ··· <2N - 1> → <2N>. That is, the CPU estimates that the Li ions enter in order from <1> to <2N> along the magnitude of the numbers.

[0049] When the process of S12 is performed, at S15, the CPU determines whether the internal resistance value Z is greater than 2Y. If it determines Yes, the CPU proceeds to S16 and estimates that the Li ions enter the surface layer portion 31 (<5>) of the third layer component 30. On the other hand, if it determines No, the CPU proceeds to S17 and estimates that the Li ions enter the deep layer portion 32 (<2>) of the first layer component 30. Further, the CPU proceeds to S18 and estimates that the Li ions enter in the order of <5> → <4> → <7> → <6> → <9> → ··· <2N - 4> → <2N - 1> → <2N - 2> → <2N>. That is, after the Li ions enter the deep layer portion 32 (<2>) of the first layer component 30, the CPU estimates that the Li ions enter in the order of the surface layer portion 31 of the (N - 1)th layer component 30 → the surface layer portion 31 of the Nth layer component 30 → the deep layer portion 32 of the (N - 1)th layer component 30 → the deep layer portion 32 of the Nth layer component 30.

[0050] When the process of S16 is performed, the CPU determines at S19 whether the internal resistance value Z is greater than 3Y. If it is determined to be Yes, the CPU proceeds to S20 and estimates that Li ions enter the surface layer portion 31 (<7>) of the fourth layer component 30. On the other hand, if it is determined to be No, the CPU proceeds to S21 and estimates that Li ions enter the deep layer portion 32 (<2>) of the first layer component 30. Further, the CPU proceeds to S22 and estimates that Li ions enter in the order of <7> → <4> → <9> → <6> → ··· <2N - 1> → <2N - 4> → <2N - 2> → <2N>. That is, the CPU estimates that Li ions enter in the order of the surface layer portion 31 of the (N - 2)-th layer component 30 → the surface layer portion 31 of the (N - 1)-th layer component 30 → the surface layer portion 31 of the N-th layer component 30 → the deep layer portion 32 of the (N - 2)-th layer component 30 → the deep layer portion 32 of the (N - 1)-th layer component 30 → the deep layer portion 32 of the N-th layer component 30.

[0051] When the process of S20 is performed, the CPU determines at S23 whether the internal resistance value Z is greater than ((N / 2) - 2)Y. If it is determined to be Yes, the CPU proceeds to S24 and estimates that Li ions enter the surface layer portion 31 (<2N - 3>) of the (N - 1)-th layer component 30. On the other hand, if it is determined to be No, the CPU proceeds to S25 and estimates that Li ions enter the deep layer portion 32 (<2>) of the first layer component 30. Further, the CPU proceeds to S26 and estimates that Li ions enter in the order of <2N - 3> → <4> → <2N - 1> → <6> → <8> → ··· <2N - 4> → <2N - 2> → <2N>. That is, the CPU estimates that Li ions enter each surface layer portion 31 of the first layer component 30 to the (N - 2)-th layer component 30 in this order, and then enter the deep layer portion 32 of the first layer component 30 → the surface layer portion 31 of the (N - 1)-th layer component 30 → the deep layer portion 32 of the second layer component 30 → the surface layer portion 31 of the N-th layer component 30, and then enter each deep layer portion 32 of the third layer component 30 to the N-th layer component 30 in this order.

[0052] When the process of S24 is performed, the CPU determines at S27 whether the internal resistance value Z is greater than ((N / 2)-1)Y. If it is determined to be Yes, the CPU proceeds to S28 and estimates that Li ions enter the surface layer portion 31 (<2N - 1>) of the Nth layer component 30. Subsequently, the CPU proceeds to S29 and estimates that Li ions enter in the order of <2> → <4> → <6> → <8> → ··· <2N - 4> → <2N - 2> → <2N>. That is, the CPU estimates that Li ions enter each surface layer portion 31 of the first layer component 30 to the Nth layer component 30 in this order, and then enter each deep layer portion 32 of the first layer component 30 to the Nth layer component 30 in this order.

[0053] On the other hand, if it is determined to be No at S27, the CPU proceeds to S30 and estimates that Li ions enter the deep layer portion 32 (<2>) of the first layer component 30. Further, the CPU proceeds to S31 and estimates that Li ions enter in the order of <2N - 1> → <4> → <6> → <8> → ··· <2N - 4> → <2N - 2> → <2N>. That is, the CPU estimates that Li ions enter each surface layer portion 31 of the first layer component 30 to the (N - 1)th layer component 30 in this order, then enter the deep layer portion 32 of the first layer component 30, and subsequently enter the surface layer portion 31 of the Nth layer component 30, and then enter each deep layer portion 32 of the second layer component 30 to the Nth layer component 30 in this order.

[0054] Therefore, the charge-discharge amount calculation unit 402 (CPU) performs the process of the flowchart in FIG. 7 using the internal resistance value Z at the current time obtained by the resistance value estimation unit 401, thereby estimating the intercalation state of Li ions in each layer component 30 (surface layer portion 31, deep layer portion 32) at an arbitrary time when the charge control of the all-solid-state battery 20 is executed. That is, the charge-discharge amount calculation unit 402 can accurately estimate the amount of Li ions that can be intercalated in the surface layer portion 31 of the layer component 30.

[0055] Furthermore, when the all-solid-state battery 20 is under discharge control, the movement of Li ions is opposite to that when the all-solid-state battery 20 is under charge control. Therefore, the charge / discharge amount calculation unit 402 (CPU) can estimate the intercalation state of Li ions in each layer component 30 at any time when the charge control of the all-solid-state battery 20 is executed.

[0056] Furthermore, the charge / discharge amount calculation unit 402 calculates the SOC, discharge amount, and charge amount of the all-solid-state battery 20 when a predetermined time has elapsed from the current time based on route information, which is information regarding the driving route that the vehicle 10 is scheduled to drive on. That is, the SOC, discharge amount, and charge amount at a plurality of times are calculated. Hereinafter, the SOC, discharge amount, and charge amount of the all-solid-state battery 20 calculated by the charge / discharge amount calculation unit 402 are referred to as target power amounts Tq. For example, when the vehicle 10 drives uphill, power is discharged from the all-solid-state battery 20 and supplied to the drive source 50 (electric motor). On the other hand, when the vehicle 10 drives downhill, the power generated by the electric motor is charged to the all-solid-state battery 20. For example, the charge / discharge amount calculation unit 402 acquires route information from a navigation system mounted on the vehicle 10. For example, assume a case where the vehicle 10 drives downhill after passing an uphill. In this case, the charge / discharge amount calculation unit 402 calculates the required charge amount (and SOC) before reaching the uphill, the discharge amount (and SOC) when driving uphill, and the charge amount (and SOC) when driving downhill. At this time, the charge / discharge amount calculation unit 402 calculates the target power amount Tq so that lithium does not precipitate in the negative electrode active material layer 25 when the all-solid-state battery 20 is charged with power.

[0057] The charge / discharge control unit 403 performs charge / discharge control of the all-solid-state battery 20 based on the target power amounts Tq at a plurality of times obtained by the charge / discharge amount calculation unit 402. That is, the charge / discharge control unit 403 performs charge / discharge control of the all-solid-state battery 20 so that the SOC of the all-solid-state battery 20 at any time becomes the SOC included in the target power amount Tq.

[0058] Thus, in this embodiment Ion Acceptable State Estimation DeviceEstimates the internal resistance value Z when Li ions move from the outer peripheral edge side to the center side of each layer component 30 of the negative electrode active material layer 25, taking into account the elapsed time of the all-solid-state battery 20. Furthermore, Ion Acceptable State Estimation Device Estimates, with high accuracy, the amount of Li ions that can be intercalated into the surface layer portion 31 of each layer component 30, taking into account the estimated internal resistance value Z. Therefore, Ion Acceptable State Estimation Device Can estimate the Li-ion acceptance state in the negative electrode active material layer 25 with high accuracy as compared with the case where the internal resistance value Z is not taken into account.

[0059] Generally, since the surface resistance value Y of each layer component 30 is smaller than the internal resistance value Z, Li ions are more likely to be intercalated into the surface layer portion 31 than into the deep layer portion 32 during the execution of charge control. Therefore, if the amount of Li ions that can be intercalated into each surface layer portion 31 can be estimated as in this embodiment, charge control of the all-solid-state battery 20 can be executed so that lithium does not precipitate in the negative electrode active material layer 25.

[0060] Furthermore, each layer component 30 contains lithium titanate (LTO). Therefore, the negative electrode 27 has a smaller potential fluctuation (reaction driving force) when the SOC is at the value in the normal use state as compared with the case where each layer component 30 does not contain lithium titanate. Therefore, in this embodiment, Ion Acceptable State Estimation Device Can estimate the Li-ion acceptance state in the negative electrode active material layer 25 with higher accuracy as compared with the case where each layer component 30 does not contain lithium titanate.

[0061] As described above, regarding the all-solid-state battery according to the embodiment, Ion Acceptable State Estimation Device Although described, these can be appropriately designed and changed within the scope not departing from the gist of the present invention.

[0062] For example, assuming that each layer component 30 has three parts with different positions in the direction connecting the center and the outer peripheral edge of the layer component 30, the internal resistance value Z may be estimated. In this case, compared with the case where each layer component 30 is considered to have only two parts (the surface layer part 31 and the deep layer part 32), the internal resistance value Z can be estimated with higher accuracy. Therefore, in this case, the receivable state of Li ions in the negative electrode active material layer 25 can be estimated with higher accuracy. However, in the case where each layer component 30 is considered to have only two parts, the amount of ions that can be received by the part (surface layer part 31) located on the outermost peripheral edge side of each layer component 30 can be estimated more easily.

Explanation of Signs

[0063] 20 All-solid-state battery 23 Positive electrode 24 Solid electrolyte layer 25 Negative electrode active material layer 30 Layer component 31 Surface layer part (part) 32 Deep layer part (part) 40 Battery control ECU( Ion Acceptable State Estimation Device ) 401 Resistance value estimation unit 402 Charge and discharge amount calculation unit (receiving capacity estimation unit) L Straight line R Resistance value

Claims

1. An ion-acceptable state estimation device for estimating an ion-acceptable state in a negative electrode active material layer of a negative electrode in an all-solid-state battery in which a positive electrode, a solid electrolyte layer, and a negative electrode are arranged linearly in this order, wherein the negative electrode active material layer of the negative electrode includes a plurality of layer components arranged linearly, each of the layer components is divided into a plurality of parts according to a position in a direction connecting the center and the outer peripheral edge of the layer component, a resistance value estimation unit that estimates a resistance value when ions move from the outer peripheral edge side to the center side between adjacent parts, taking into account the elapsed time from a predetermined time of the all-solid-state battery, a capacitance estimation unit that estimates an ion amount that can be accepted by the part located on the outermost peripheral edge side of each layer component, taking into account the resistance value, comprising, When the capacitance estimation unit estimates that the ions enter the surface layer part, which is the part on the outermost peripheral edge side of the target layer component, which is a predetermined layer component, if the internal resistance value when the ions move from the surface layer part of the target layer component to the deep layer part, which is the part on the center side of the target layer component from the surface layer part, is larger than the surface resistance value when the ions move from the target layer component to the surface layer part of the layer component adjacent to the target layer component, it is estimated that the ions enter the surface layer part of the adjacent layer component, and when the internal resistance value is less than or equal to the surface resistance value, it is estimated that the ions enter the deep layer part of the target layer component. An ion-acceptable state estimation device for an all-solid-state battery.

2. The ion-acceptable state estimation device for an all-solid-state battery according to claim 1, wherein each of the layer components has a surface layer part, which is the part located on the outermost peripheral edge side, and a deep layer part, which is located on the inner peripheral side of the surface layer part.

3. The ion-acceptable state estimation device for an all-solid-state battery according to claim 1 or claim 2, wherein the negative electrode active material layer contains lithium titanate.

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