power storage device

Abstract

The present application relates to a power storage device, and a method for controlling the power storage device. The power storage device includes a power storage module, a laminate housing that houses the power storage module in a state where the inside is depressurized, a pressure detection unit that is provided inside the laminate housing and detects an internal pressure as a resistance value in a state where the pressure detection unit is in contact with the laminate housing, a temperature detection unit that detects a temperature of the power storage module, and a control unit that controls the pressure detection unit. The control unit performs the following processing: in a case where the temperature of the power storage module detected by the temperature detection unit is less than a predetermined temperature, detection based on the pressure detection unit is not performed; and in a case where the temperature of the power storage module detected by the temperature detection unit is equal to or more than the predetermined temperature, detection based on the pressure detection unit is performed, and a correction value is determined in accordance with the temperature of the power storage module, and the resistance value detected by the pressure detection unit is corrected by the correction value.

Description

Technical Field

[0001] This invention relates to an energy storage device. Background Technology

[0002] Patent Document 1 discloses an anomaly detection device configured to be in close contact with the outer surface of a battery. The anomaly detection device includes a pressure sensing sensor that detects pressure changes of a fluid accompanying deformation of the battery, and detects battery anomalies by measuring the deformation of the battery based on the pressure sensing sensor.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2018-125264 Summary of the Invention

[0004] Laminated batteries have a structure in which an energy storage module is housed within an outer casing. Although the energy storage module housed within the casing is constrained by the decompression force generated by atmospheric pressure, the generation of vapor pressure or gas within the module causes the internal pressure of the casing to recover. Since this internal pressure recovery affects battery performance, methods are known to detect pressure recovery using pressure sensors when the internal pressure rises to a specified level. However, because the detection timing is often premature due to the accuracy deviation of the pressure sensor, the detection rate increases, leading to an increased false detection rate.

[0005] The present invention was made in view of the above circumstances, and its object is to provide an energy storage device that can reduce the false detection rate of the pressure sensing sensor in a structure that detects the pressure inside the outer casing by means of a pressure sensing sensor.

[0006] The energy storage device of the present invention is characterized by comprising: an energy storage module; a laminated outer casing that houses the energy storage module in a depressurized state; a pressure detection unit disposed inside the laminated outer casing and detecting the internal pressure as a resistance value when in contact with the laminated outer casing; a temperature detection unit that detects the temperature of the energy storage module; and a control unit that controls the pressure detection unit to perform the following processing: if the temperature of the energy storage module detected by the temperature detection unit is less than a predetermined temperature, the detection based on the pressure detection unit is not performed; and if the temperature of the energy storage module detected by the temperature detection unit is above the predetermined temperature, the detection based on the pressure detection unit is performed, and a correction value is determined based on the temperature of the energy storage module, and the resistance value detected by the pressure detection unit is corrected by the correction value.

[0007] Invention Effects

[0008] In this invention, the false detection rate of the pressure sensor can be reduced in a structure that detects the pressure inside the outer casing by means of a pressure sensing sensor. Attached Figure Description

[0009] Figure 1 This is a schematic diagram illustrating the energy storage device in the embodiment.

[0010] Figure 2 This is a diagram illustrating the configuration of a pressure sensor.

[0011] Figure 3 This diagram illustrates the situation where the energy storage module is constrained under reduced pressure inside the outer casing.

[0012] Figure 4 It is a graph showing the relationship between the correction value and temperature.

[0013] Figure 5 This is a flowchart illustrating the pressure testing process. Detailed Implementation

[0014] The energy storage device in the embodiments of the present invention will be described in detail below. However, the present invention is not limited to the embodiments described below.

[0015] Figure 1 This diagram schematically illustrates the energy storage device in the embodiment. The energy storage device 1 is a bipolar lithium-ion battery. The energy storage device 1 includes an energy storage module 2, an outer casing 3, a pressure sensor 4, internal components 5, a temperature sensor 6, and a control unit.

[0016] The energy storage module 2 has an electrode stack having multiple bipolar electrodes stacked on top of each other and a sealing portion for sealing the electrode stack. The energy storage module 2 is formed in a cuboid shape. When viewed from the stacking direction, the energy storage device 1 is formed in a quadrilateral shape.

[0017] The outer casing 3 is a laminated body that houses the energy storage module 2. The outer casing 3 is made of aluminum laminate. The interior of the outer casing 3 is a vacuum state. Inside the outer casing 3, in addition to housing the energy storage module 2, it also houses the pressure sensing sensor 4 and internal components 5.

[0018] A pressure sensor 4 is disposed inside the outer casing 3 and serves as a pressure detection unit for detecting the pressure inside the outer casing 3. The pressure sensor 4 is installed inside the outer casing 3, which is in a vacuum state. The pressure sensor 4 is disposed between the inner component 5 and the outer casing 3 in the stacking direction. The pressure sensor 4 has a pressure sensing portion on the surface opposite the outer casing 3 in the stacking direction. The resistance value of this pressure sensing portion varies depending on the contact area.

[0019] The internal component 5 is made of insulating resin. The internal component 5 is positioned opposite the side of the energy storage module 2 and is arranged in the stacking direction opposite the outer casing 3. It has a flat portion 5a that functions as its upper surface.

[0020] like Figure 2 As shown, the pressure sensor 4 is disposed on the planar portion 5a. The pressure sensor 4 has a pressure sensing part arranged along the planar portion 5a. The mounting position of the pressure sensor 4 is not on the upper surface of the energy storage module 2, but rather on the planar portion 5a formed in the internal space of the outer casing 3. As a result, the influence of planar deformation of the energy storage module 2 on the pressure sensor 4 can be eliminated, thereby obtaining stable accuracy.

[0021] Pressure sensor 4 can measure pressures from 0 to 100 kPa (absolute pressure). For example... Figure 3 As shown, the energy storage module 2, housed inside the outer casing 3, is constrained by a decompression force caused by atmospheric pressure. The wiring for the pressure sensor 4 is led out from the outside of the outer casing 3 via an FPC. The pressure sensor 4 is connected to the control unit via wiring. The pressure sensor 4 is controlled by the control unit.

[0022] Temperature sensor 6 is disposed on the exterior of the casing 3 and is a temperature detection unit for detecting the temperature of the battery storage module 2. For example, temperature sensor 6 is disposed above the battery storage module 2 and is provided on the outer surface of the casing 3. Temperature sensor 6 measures the temperature of the battery storage module 2 via the casing 3.

[0023] The control unit is a control device that controls the pressure sensor 4. Based on the pressure information detected by the pressure sensor 4, the control unit notifies that the internal pressure of the laminated outer casing 3 needs to be reduced.

[0024] In the energy storage device 1, to suppress output deviation caused by the temperature of the pressure sensor 4, the pressure sensor 4 is configured not to perform pressure detection until a predetermined temperature T1 is exceeded. The control unit controls the system to prevent detection based on the pressure sensor 4 from being performed until the temperature of the energy storage module 2 exceeds the predetermined temperature T1. That is, the detection by the pressure sensor 4 is stopped by the control unit based on the battery temperature. The predetermined temperature T1 is set to the temperature exceeding the detection threshold in the theoretical range. The predetermined temperature T1 refers to the detection start temperature. For example, the predetermined temperature T1 is 20 to 40°C.

[0025] When the temperature of the energy storage module 2 exceeds the specified temperature range (high-temperature side), the resistance correction portion caused by the temperature effect of the pressure sensor 4 is corrected and detected based on the battery temperature detected by the temperature sensor 6. When the temperature of the energy storage module 2 exceeds the specified temperature, the control unit determines the corrected value by multiplying the detected value by the corrected value based on the temperature characteristics of the pressure sensor 4. The corrected value is different for each temperature. For example... Figure 4 As shown, the correction value becomes greater than 1 as the temperature increases.

[0026] Figure 5 This is a flowchart illustrating the pressure testing process. Figure 5 The control shown is implemented by the control unit.

[0027] The control unit acquires information related to the temperature of the energy storage module 2 as measured by the temperature sensor 6 (step S1). In step S1, the battery temperature is measured by the temperature sensor 6.

[0028] The control unit determines whether the battery temperature is above the specified temperature T1 (step S2).

[0029] If the battery temperature is determined to be below the specified temperature T1 (step S2: No), the control routine returns to step S1. If the temperature of the energy storage module 2 detected by the temperature sensor 6 is below the specified temperature T1, the control unit does not perform detection based on the pressure sensor 4.

[0030] If the battery temperature is determined to be above the specified temperature T1 (step S2: Yes), the control unit performs detection based on the pressure sensor 4 (step S3). In step S3, the pressure sensor 4 begins to measure the resistance value.

[0031] The control unit determines a correction value based on the battery temperature (step S4). Based on... Figure 4 The temperature is correlated with a map to determine the correction value.

[0032] The control unit calculates the corrected resistance value by multiplying the correction value by the resistance value measured by the pressure sensor 4 (step S5). If the temperature of the energy storage module 2 detected by the temperature sensor 6 is above the specified temperature T1, the control unit performs detection based on the pressure sensor 4, determines the correction value according to the temperature of the energy storage module 2, and corrects the resistance value detected by the pressure sensor 4 using the correction value.

[0033] The control unit determines whether the corrected resistance value is greater than or equal to the specified resistance value R1 (step S6).

[0034] If the corrected resistance value is determined to be greater than or equal to the specified resistance value R1 (step S6: Yes), the control unit notifies that the internal pressure of the laminated outer casing 3 needs to be reduced (step S7). If step S7 is performed, the control routine ends.

[0035] If it is determined that the corrected resistance value is not greater than the specified resistance value R1 (step S6: No), the control routine returns to step S1.

[0036] In the energy storage device 1 configured in this way, the degree of deformation of the outer casing 3 varies depending on the temperature of the energy storage module 2. Therefore, even if the internal pressure of the outer casing 3 is the same, the resistance value detected by the pressure sensor 4 will change according to the temperature of the energy storage module 2. Since the resistance value is corrected based on the temperature detected by the temperature sensor 6, the temperature-induced change in resistance value can be suppressed.

[0037] As explained above, according to the implementation method, the false detection rate of the pressure sensing sensor 4 can be reduced.

[0038] Furthermore, by positioning the pressure sensor 4 between the planar portion 5a and the outer body 3, rather than on the outer surface of the outer body 3, the detection accuracy based on the pressure sensor 4 is improved.

[0039] Furthermore, as the temperature detected by temperature sensor 6 increases, the correction value (correction coefficient) gradually increases. This improves the accuracy of the corrected resistance value.

[0040] Alternatively, corrections can be made for each temperature on the low-temperature side as well. These corrections can offset temperature-induced shifts, but not deviations. Therefore, a decision system that does not require testing is preferable.

[0041] Furthermore, the control unit can perform control measures in step S7, such as applying a temperature limit to the energy storage module 2, to suppress the pressure rise inside the outer casing 3.

[0042] Furthermore, it can be configured such that the sign of the correction coefficient changes by using a certain temperature as a threshold. In this case, the accuracy of the corrected resistance value is improved.

[0043] Symbol Explanation

[0044] 1-Energy storage device, 2-Energy storage module, 3-External casing, 4-Pressure sensor, 5-Internal components, 6-Temperature sensor.

Claims

1. An energy storage device, characterized in that, have: Energy storage module; A laminated outer casing that houses the energy storage module while its interior is under depressurized conditions; A pressure detection unit is disposed inside the laminated outer casing and detects the internal pressure as a resistance value when in contact with the laminated outer casing. Temperature detection unit, which detects the temperature of the energy storage module; and The control unit controls the pressure detection unit. The control unit performs the following processing: If the temperature of the energy storage module detected by the temperature detection unit is lower than a specified temperature, the detection based on the pressure detection unit will not be performed; and If the temperature of the energy storage module detected by the temperature detection unit is above the specified temperature, the detection based on the pressure detection unit is performed, and a correction value is determined based on the temperature of the energy storage module, and the resistance value detected by the pressure detection unit is corrected by the correction value.

2. The energy storage device according to claim 1, characterized in that, have: Internal components, which are located inside the laminated outer casing and are arranged opposite the side of the energy storage module, The pressure detection unit is a pressure sensing sensor disposed on the flat part of the internal component.

3. The energy storage device according to claim 2, characterized in that, The pressure sensor has a pressure sensing part that is held between the planar part and the laminated outer casing.

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