JP2014127341A - Battery state detection system and battery state detection method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a battery state detection system and battery state detection method, capable of improving detection precision of a battery state.SOLUTION: The present invention comprises: in an internal space formed by sealing with an exterior member 111, a battery that outfits a power generation element 112; volumetric change measurement means that measures a volumetric change in the air of the internal space; and detection means that detects a battery state from the volumetric change measured by the volumetric change measurement means.

Description

  The present invention relates to a battery state detection system and a battery state detection method for detecting the state of a battery.

  The volume change of the positive electrode and the negative electrode stored in the case of the secondary battery is detected, the temperature of the electrode is detected, and based on the detected volume change and temperature, the correlation of the battery is set in advance. A state estimation system for a secondary battery that estimates the input / output possible power of the secondary battery and the full charge capacity, which are state quantities that reflect the degree of deterioration, is disclosed (see, for example, Patent Document 1).

JP 2006-12761 A

  However, since the state estimation system of the secondary battery only detects the volume change of the electrode and does not measure the volume change of the gas generated in the secondary battery, the battery state detection accuracy is low. There was a problem.

  The problem to be solved by the present invention is to provide a battery state detection stem and a battery state detection method with improved battery state detection accuracy.

  This invention solves the said subject by measuring the volume of the gas in the internal space formed of the exterior member, and detecting the state of a battery from the measured volume of the gas.

  Since the present invention measures the volume change of the gas in the internal space of the battery, which has a correlation with the battery state, for example, it is possible to accurately grasp the change in the battery state that occurs when the battery deteriorates. As a result, the detection accuracy of the battery state can be increased.

It is a block diagram of the battery state detection system which concerns on embodiment of this invention. It is sectional drawing of the assembled battery of FIG. It is sectional drawing of the battery module of FIG. It is a perspective view of the cell 11 of FIG. FIG. 4 is an exploded perspective view of the cell of FIG. 3. It is sectional drawing which follows the VI-VI line of FIG. It is sectional drawing of the assembled battery which expanded the circumference | surroundings of the sensor of FIG. 5 is a graph showing a characteristic of thickness with respect to the remaining capacity of the cell in the cell of FIG. 5 is a graph showing a characteristic of thickness with respect to the remaining capacity of the cell in the cell of FIG. It is a flowchart which shows the control procedure of the controller unit of FIG. 6 is a flowchart showing a control procedure of a controller unit in a battery state detection system according to another embodiment of the present invention. It is sectional drawing of the assembled battery of the battery state detection system which concerns on other embodiment of this invention. (A) is sectional drawing of the assembled battery at the time of expansion | swelling by deterioration, (b) is sectional drawing of the assembled battery at the time of expansion | swelling by gas generation. 7 is a flowchart showing a control procedure of a controller unit in a battery state detection system according to another embodiment of the invention. 6 is a graph showing a characteristic of a thickness with respect to a remaining capacity of a cell in a battery state detection system according to another embodiment of the invention. 7 is a flowchart showing a control procedure of a controller unit in a battery state detection system according to another embodiment of the invention. It is a block diagram of the battery state detection system which concerns on other embodiment of invention. In the battery state detection system which concerns on other embodiment of invention, sectional drawing of a battery module is shown. It is sectional drawing of the battery module which expanded the circumference | surroundings of the sensor of FIG. It is a top view of the cell of FIG. It is a top view of the cell of FIG. It is a flowchart which shows the control procedure of the controller unit of FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<< First Embodiment >>
FIG. 1 is a block diagram of a battery state detection system according to an embodiment of the present invention. The battery state detection system of this example is a system that is mounted on a vehicle such as an electric vehicle or a hybrid vehicle and detects the battery state of the vehicle. In addition, the battery state detection system of this example may be mounted on a vehicle other than the electric vehicle, or may be mounted on a device other than the vehicle.

  As shown in FIG. 1, the battery state detection system of this example includes an assembled battery 1 and a controller 2. The assembled battery 1 is a power source of a motor mounted on a vehicle, and includes a plurality of secondary batteries. The controller 2 is a controller for detecting the battery state of the assembled battery.

  The structure of the assembled battery 1 is demonstrated using FIGS. 2 is a cross-sectional view of the assembled battery 1, FIG. 3 is a cross-sectional view of the battery module, FIG. 4 is a perspective view showing a completed state of the cell (unit cell), and FIG. 5 is an exploded view of main components of the cell. It is a disassembled perspective view. 6 is a cross-sectional view taken along line VI-VI in FIG.

  As shown in FIG. 2, the assembled battery 1 includes a plurality of battery modules 10, a restraint plate 14, a sensor 15, bolts 16, and nuts 17.

  First, the configuration of the battery module 10 will be described with reference to FIG. The battery module 10 includes a plurality of cells 11 and a case 13. Each of the cells 11 is a laminated battery (flat battery) formed in a plate shape. The plurality of cells 11 are stacked together to form a stacked body. Note that the number of cells 11 is not necessarily four, and may be one.

  The case 13 is a housing for accommodating a plurality of cells 11. The case 13 is made of metal or the like. A side surface along a plane parallel to the stacking direction of the plurality of cells 11 (Z direction in FIG. 3) and a surface along a direction perpendicular to the stacking direction (Y direction in FIG. 3). Upper and lower main surfaces are opposed to each other.

  The main surface of the case 13 has a protrusion 131 formed by protruding from the outside toward the cell 11 at the center of the main surface. In other words, the main surface of the case 13 has a concave projecting portion 131 whose central portion is recessed toward the cell 11. In FIG. 3, the protrusions 131 are formed on the upper and lower main surfaces of the case 13, respectively, but may be formed on either one of the upper and lower surfaces.

  The protruding portion 131 is formed to suppress the expansion of the cell 11 while increasing the rigidity of the main surface of the case 13. The battery module 10 of this example is configured by stacking a plurality of flat cells 11. When gas is generated in the cell 11, the cell 11 tends to swell in the stacking direction. Therefore, in this example, the plurality of cells 11 are projected by projecting the surface of the case 13 toward the cells 11 in the stacking direction by the projecting portion 131 while holding the plurality of cells 11 on the main surface of the case 13. Suppression of the expansion.

  Next, the configuration of the cell 11 will be described with reference to FIGS. The cell 11 of this example includes a thin and flat battery main body 110 and a spacer 120.

  The battery main body 110 is configured such that a power generation element 112 is accommodated in a laminated film exterior member 111 and an outer peripheral portion 113 of the exterior member 111 is sealed. The detailed configuration of the power generation element 112 is shown in FIG. The laminate film constituting the exterior member 111 has a plurality of layered structures and is formed of a flexible laminate film (film-like member) such as a resin-metal thin film laminate material.

  The exterior member 111 is composed of a pair of laminate films, and a rectangular flat plate is formed into a shallow bowl (dish shape) so that the power generation element 112 can accommodate one of the pair of laminate films. After the electrolytic solution is put, the other laminate film is covered and the respective outer peripheral portions 113 are overlapped, and the entire periphery of the outer peripheral portion 113 is bonded by heat fusion or an adhesive to form a bonded portion.

  The cell 11 of this example is a lithium ion secondary battery. As shown in FIG. 6, the power generation element 112 is configured by laminating a separator 112c between a positive electrode plate 112a and a negative electrode plate 112b. The power generation element 112 of this example includes three positive electrode plates 112a, five separators 112c, three negative electrode plates 112b, and an electrolyte (electrolyte) (not shown). In addition, the cell 11 which concerns on this invention is not limited to a lithium ion secondary battery, Another battery may be sufficient. The stacking direction of the electrode plates 112a and 112b and the stacking direction of the cells 11 are the same direction.

  The positive electrode plate 112a constituting the power generation element 112 includes a positive current collector 112d extending to the positive terminal 114 and a part of both main surfaces of the positive current collector 112d (the stacking direction of the current collector 112d is normal) And positive electrode layers 112e and 112f formed respectively on the surface.

The positive electrode side current collector 112d of the positive electrode plate 112a is formed of a metal foil such as aluminum. The positive electrode layers 112e and 112f of the positive electrode plate 112a include a positive electrode active material such as manganese nickelate (LiNn ₂ O ₄ ) and are formed on both main surfaces of the positive electrode current collector plate 112d.

  The negative electrode plate 112b constituting the power generation element 112 includes a negative electrode side current collector 112g extending to the negative electrode terminal 115 and negative electrode layers 112h and 112i formed on both main surfaces of a part of the negative electrode side current collector 112g, respectively. And have.

  The negative electrode side current collector 112g of the negative electrode plate 112b is formed of a metal foil such as copper. The negative electrode layers 112h and 112i of the negative electrode plate 112b include a negative electrode active material such as natural graphite, and are formed on both main surfaces of the negative electrode current collector plate 112g.

  The separator 112c laminated between the positive electrode plate 112a and the negative electrode plate 112b prevents a short circuit between the positive electrode plate 112a and the negative electrode plate 112b, and may have a function of holding an electrolytic solution. The separator 112c is a microporous film formed of, for example, polypropylene, and has a function of blocking the current by closing the pores of the layer due to heat generation when an overcurrent flows.

  The above power generation element 112 is formed by alternately stacking positive plates 112a and negative plates 112b with separators 112c interposed therebetween. The three positive electrode plates 112a are connected to a positive electrode terminal 114 made of metal foil. Although not shown in FIG. 5, the three negative plates 112b are connected to the negative electrode terminals 115 made of metal foil.

  As shown in FIG. 6, a positive electrode terminal 114 and a negative electrode terminal 115 are led out of the exterior member 111 from each of the positive electrode plate 112 a and the negative electrode plate 112 b of the power generation element 112. In the secondary battery 1 of this example, the positive electrode terminal 114 and the negative electrode terminal 115 are led side by side from the outer peripheral portion 113 of one side of the exterior member 111 (short side in front of FIG. 1). The positive electrode terminal 114 and the negative electrode terminal 115 are also referred to as a positive electrode tab 114 and a negative electrode tab 115.

  In the secondary battery 1 of this example, the positive electrode terminal 114 and the negative electrode terminal 115 are led out from the outer peripheral portion of one side of the exterior member 111. FIG. 4 shows a cross-sectional view from the positive electrode plate 112a of the power generation element 112 to the positive electrode terminal 114, and a cross section from the negative electrode plate 112b of the power generation element 112 to the negative electrode terminal 115 is omitted, but the negative electrode plate 112b and the negative electrode terminal 115 are also shown. The positive electrode plate 112a and the positive electrode terminal 114 shown in the cross-sectional view of FIG.

  That is, the battery main body 110 is laminated so that the main surfaces of the positive electrode plate 112a and the negative electrode plate 112b overlap with each other through the separator 11c. The battery body 110 is rectangular in plan view, and the outer periphery 113 of the rectangle is joined with a pair of laminate films (aluminum laminate exterior body) in the exterior member 111 to seal the inside. Thereby, the secondary battery 1 becomes a laminate side battery. Note that the outer shape of the battery body 11 is not limited to a rectangle, and can be formed in a square or other polygons.

  The battery body 110 configured as described above is connected and combined with one or more other secondary batteries and used as a secondary battery having a desired output and capacity.

  As shown in FIGS. 4 and 5, the spacer 120 of the present example is disposed between the outer peripheral portions 113 of the adjacent battery main bodies 110, and the battery from between the outer peripheral portions 113 of the adjacent battery main bodies 11. The battery main body 11 has a fixing part 121 for fixing the battery main body 11 to another battery main body 11.

  The spacer 120 is formed of a rigid insulating resin material such as polybutylene terephthalate (PBT), and is formed in a long shape having a length equal to or longer than the length of the short side of the outer peripheral portion of the battery body 11. Fixing portions 121 made of sheath-shaped through holes are formed at both ends of the spacer 120.

  By inserting a fastening member such as a screw into the insertion hole formed in the fixing portion 121 of each cell 11 and fastening it, a plurality of cells 11 are connected as shown in FIG. 11 laminates are constructed. In addition, the structure which fixes the some cell 11 is not necessarily the structure which provides the fixing part 121 in the spacer 120, and fastens it with a fastening member, Other structures may be sufficient. And the battery module 10 is comprised by accommodating the laminated body of this cell 11 in the case 13. FIG.

  Returning to FIG. 2, a plurality of battery modules 10 are stacked such that the main surfaces of the case 13 overlap each other. When the plurality of battery modules 10 are stacked, the projecting portion 131 forms a space between the plurality of battery modules. This space is a space that absorbs the swelling of the cells 11 in the stacking direction. In FIG. 2, four battery modules 10 are stacked, but a plurality of battery modules need not necessarily be stacked, and the number of battery modules 10 in stacking may be any number.

  The restraint plate 14 is a member that is formed in a pair of plates and restrains the stacked body of the battery modules 10. The restraint plates 14 are respectively arranged on the main surface of the uppermost battery module 10 in the stacking direction and the main surface of the lowermost battery module 10 in the stacking direction, and the stack of the battery modules 10 is arranged. It is arranged to hold it.

  Through holes for passing bolts 16 are formed in the case 13 and the restraining plate 14 of each battery module 10. And the several battery module 10 and the restraint board 14 are being fixed by passing the volt | bolt 16 through the said through-hole and fastening the nut 17 from the front-end | tip of the volt | bolt 16.

  A sensor 15 is provided between the head of the bolt 16 and the restraining plate 14. The sensor 15 is a sensor for measuring the displacement of the cell 11, and for example, a strain sensor or a pressure sensor is used as the sensor 15. The sensor 15 is covered with an elastic material such as rubber so that it is easily expanded and contracted by the displacement of the cell 11.

  The force applied to the sensor 15 will be described with reference to FIG. FIG. 7 is an enlarged cross-sectional view of a portion where the sensor 15 is provided in the cross-sectional view of the assembled battery 1 shown in FIG.

  The battery module 10 expands mainly in the stacking direction (Z direction in FIG. 7) due to the expansion of the electrodes and the generation of gas accompanying the deterioration of the battery. Further, gas may be generated due to an abnormality of the cell 11 in the battery module 10, and the battery module 10 may expand.

  When the battery module 10 expands, the thickness of the cells 11 in the stacking direction increases. On the main surface of the case 13, the protruding portion 131 is pushed out to the cell 11 and applies a stress in the Z direction to the restraining plate 14. The restraint plate 14 receives the stress and is pushed outward. At this time, since the sensor 15 is sandwiched between the head of the bolt 16 and the restraint plate 14, the sensor 15 receives pressure from the restraint plate 14 due to the outward stress of the restraint plate 14 and compresses it. To do. The sensor 15 detects distortion due to the pressure from the restraint plate 14 and transmits the detected value to the controller unit 2 as an electric signal.

  Returning to FIG. 1, the configuration of the controller unit 2 will be described. The controller unit 2 is a controller that controls the entire system in an integrated manner, and includes a battery thickness measurement unit 21, a battery state detection unit 22, and a remaining capacity measurement unit 23.

  The battery thickness measurement unit 21 measures the thickness of the cell 11 based on the detection value of the sensor 15. The magnitude of the pressure applied to the sensor 15 from the restraint plate 14 has a correlation with the expansion of the cells 11 in the stacking direction, in other words, the thickness of the cells 11. Therefore, the battery thickness measurement unit 21 detects the detection value of the sensor 15 (the strain amount of the sensor 15), the pressure due to the fastening between the head of the bolt 16 and the restraint plate 14, and the increase amount of the thickness of the cell 11. , The thickness of the cell 11 can be measured from the detection value of the sensor 15.

  Further, as described above, the expansion of the cell 11 is mainly the expansion in the stacking direction. When gas is generated and the cell 11 expands, the size of the cell 11 in the main surface direction of the cell 11 does not change. Therefore, the battery thickness measurement unit 21 measures the volume of the gas in the cell 11 by measuring the thickness of the cell 11. In addition, the battery thickness measurement unit 21 measures the volume change of the gas generated in the cell 11 from the change in the detection value of the sensor 15.

  The battery state detection unit 22 detects the state of the cell 11 from the thickness measured by the battery thickness measurement unit 21. The remaining capacity measuring unit 23 measures the remaining capacity of the cell 11 from the detection value of a sensor (not shown) that detects each voltage or current of the cell 11 provided in the assembled battery 1. The remaining capacity measuring unit 23 calculates, for example, the charged capacity charged in each cell 11 by integrating input / output currents to the assembled battery 1, and calculates the remaining capacity of each cell 11. The remaining capacity measuring unit 23 may measure the remaining capacity from the voltage of the cell 11.

  Next, the thickness of the cell 11 and the battery state of the cell 11 will be described. The cell 11 deteriorates with time even in a normal state. However, when the deterioration tendency of the cell 11 is larger than the normal deterioration tendency, or when an abnormality occurs in the cell 11, the cell 11 is set so that the thickness of the cell 11 is larger than the thickness of the cell 11 at the normal time. Inflates. Therefore, in this example, by measuring the thickness of the cell 11, it is possible to detect a defective state due to abnormal deterioration of the cell 11 or a defective state due to abnormality such as a minute short circuit of the cell 11.

  A correlation between the thickness of the cell 11 and the remaining capacity will be described. As a characteristic of the cell 11, there is a correlation as shown in FIG. 8 between the thickness of the cell 11 and the remaining capacity. FIG. 8 is a graph showing the characteristics of the thickness with respect to the remaining capacity of the cell 11.

  The graph of FIG. 8 was derived by the following method. First, batteries having different remaining capacities were prepared with the cells 11 having the same shape. After measuring the remaining capacity of the battery, the thickness of the cell 11 at the time of measuring the remaining capacity was measured. And the measurement result was plotted, respectively. Thus, the present inventor has found that there is a correlation indicated by the proportional relationship in FIG. 8 between the thickness of the cell 11 and the remaining capacity of the cell 11.

  That is, since the thickness of the cell 11 changes according to the remaining capacity of the cell 11, in this example, the battery state is detected by using the remaining capacity of the cell 11 in addition to the thickness of the cell 11. Hereinafter, specific control of the battery state detection unit 22 will be described.

  The battery state detection unit 22 stores in advance a first determination threshold value indicating the defective state of the cell 1, and compares the first determination threshold value with the thickness of the cell 11 measured by the battery thickness measurement unit 21. Thus, the abnormality of the cell 11 is detected.

The first determination threshold value is a threshold value that indicates a use limit value for the deterioration of the cell 11, and corresponds to a lower limit value of the deterioration degree of the cell 11. As in this example, when the assembled battery 1 is used as a power source for a vehicle, it is necessary to stably output electric power from the cell 11 during vehicle operation. Therefore, a lower limit value (Q _lim ) of a necessary remaining capacity is predetermined for the cell 11.

FIG. 9 is a graph similar to FIG. 8, showing a characteristic of thickness with respect to the remaining capacity of the cell 11, and is a graph for explaining the first determination threshold value. As shown above, since there is a relative relationship between the remaining capacity and the thickness of the cell 11, as shown in FIG. 9, the thickness corresponding to the lower limit value (Q _lim ) of the remaining capacity is the first determination. It becomes a threshold value.

When the cell 11 is normally used and the deterioration progresses, the cell 11 expands. When the cell 11 is excessively deteriorated and the remaining capacity becomes equal to or lower than the lower limit value (Q _lim ), the thickness of the cell 11 becomes equal to or greater than the first determination threshold value. Therefore, when the thickness of the cell 11 is larger than the thickness specified by the first determination threshold, the cell 11 is in an excessively deteriorated state, and the battery state of the cell 11 is in a bad state (unusable state). Can be determined.

  When the thickness of the cell 11 measured by the battery thickness measurement unit 21 is larger than the first determination threshold, the battery state detection unit 22 determines the battery state of the cell 11 as a defective state due to excessive deterioration. When the battery state detection unit 22 determines the defective state of the cell 11, the controller unit 2 displays a lamp (not shown) in the vehicle to warn the user and indicate the defective state of the cell 11. Inform.

  On the other hand, when the thickness of the cell 11 measured by the battery thickness measurement unit 21 is smaller than the first determination threshold, the battery state detection unit 22 calculates the thickness of the cell 11 and the actual remaining capacity of the cell 11. It is used to detect the battery state of the cell 11.

  When the cell 11 is in a normal state, the remaining capacity measured by the remaining capacity measuring unit 23 and the thickness measured by the battery thickness measuring unit 21 are shown on the graph shown in FIG. Take a close value. On the other hand, when an abnormality occurs in the cell 11 and the cell 11 expands, the remaining capacity measured by the remaining capacity measuring unit 23 and the thickness measured by the battery thickness measuring unit 21 are shown in the graph of FIG. The value is far from the value. Therefore, in this example, the thickness of the cell 11 is measured by the battery thickness measuring unit 21, and the battery capacity of the normal cell 11 that is in a relative relationship with the measured thickness and the remaining capacity measuring unit 23 are measured. The state of the cell 11 is detected by comparing the actual remaining capacity of the cell 11.

  The battery state detection unit 22 stores in advance a map represented by the graph of FIG. 8, in other words, a map indicating the correlation between the remaining capacity of the cell 11 and the cell thickness. The battery state detection unit 22 refers to the map and calculates the remaining capacity (Qb) of the cell 11 corresponding to the thickness of the cell 11 measured by the battery thickness measurement unit 21. The battery state detection unit 22 calculates the difference between the actual remaining capacity (Qa) of the cell 11 measured by the remaining capacity measuring unit 23 and the remaining capacity (Qb). The difference may be an absolute value.

  A second determination threshold is preset in the battery state detection unit 22. The second determination threshold is a threshold for determining a defective state of the cell 11, and an upper limit value of the remaining capacity that can be taken by the normal cell 11 is set with respect to the thickness of the cell 11. The range of the remaining capacity that can be taken by the cell 11 is a range that is defined according to the characteristics of the cell 11 and that is set in consideration of deterioration of the normal cell 11. That is, the second determination threshold corresponds to an allowable range of the normal cell 11 thickness. Also, the second determination threshold is determined by the battery capacity, unlike the first determination threshold.

  And the battery state detection part 22 compares the difference (Qa-Qb) of remaining capacity, and a 2nd determination threshold value. If the difference is larger than the second determination threshold, the battery state detection unit 22 determines that the battery state of the cell 11 is a defective state. When the battery state is a defective state, the controller unit 2 warns the user in the same manner as described above.

  When the cell 11 is deteriorated within a normal range, the remaining capacity difference (Qa−Qb) is equal to or less than the second determination threshold value. Therefore, when the difference between the remaining capacities is smaller than the second determination threshold, the battery state detection unit 22 determines that the battery state of the cell 11 is normal.

  Next, the control procedure of the controller unit 2 will be described with reference to FIG. FIG. 10 is a flowchart showing a control procedure of the controller unit 2. The control unit 2 repeatedly performs the following control procedure at a predetermined cycle.

  In step S <b> 11, the battery thickness measurement unit 21 measures the thickness of the cell 11 from the detection value of the sensor 15 and outputs it to the battery state detection unit 22. In step S12, the battery state detection unit 22 compares the measurement value (thickness) of the battery thickness measurement unit 21 with the first determination threshold value.

  If the measured value of the battery thickness measuring unit 21 is smaller than the first determination threshold value, the remaining capacity measuring unit 23 measures the remaining capacity (Qa) of the cell 11 in step S13, and the battery state detecting unit 22 Output. In step S14, the battery state detection unit 22 refers to a map indicating the correlation between the remaining capacity and the thickness of the cell 11, and calculates the remaining capacity (Qb) corresponding to the thickness measured in step S11.

  In step S15, the battery state detection unit 22 calculates the difference between the remaining capacity (Qa) and the remaining capacity (Qb). Moreover, the battery state detection part 22 compares the difference (Qa-Qb) of remaining capacity with a 2nd determination threshold value.

  When the difference (Qa−Qb) in the remaining capacity is smaller than the second determination threshold value, in step S16, the battery state detection unit 22 determines that the cell 11 is in the normal state, and ends the control in FIG. On the other hand, when the difference (Qa−Qb) in the remaining capacity is equal to or greater than the second determination threshold, the battery state detection unit 22 determines the cell 11 as a defective state in step S17. Then, the controller unit 2 warns the user of a defective state of the cell 11 by blinking a lamp or the like, and ends the control of this example.

  Returning to step S12, if the measurement value of the battery thickness measurement unit 21 is equal to or greater than the first determination threshold, the battery state detection unit 22 causes the battery state of the cell 11 to be deteriorated excessively in step S17. The controller unit 2 issues a warning and ends the control of this example.

  As described above, this example measures the volume change of the gas (gas) in the internal space of the cell 11 by measuring the thickness of the cell 11, and from the measured volume change, the battery shape of the cell 11 is measured. Is detected. Thereby, since the state of the battery can be detected from the volume change correlated with the battery state, the change of the battery state can be accurately grasped, and as a result, the detection accuracy of the battery state is improved. Can do.

  Further, in this example, the state of deterioration of the cell 11 is detected by comparing the first determination threshold value corresponding to the lower limit value of the remaining capacity of the battery and the thickness of the cell 11 measured by the battery thickness measuring unit 21. . As a result, the cell 11 is deteriorated, and the cell 11 having a sufficiently reduced battery performance (the volume of gas in the cell 11) is set in advance as the first determination threshold value. It can be determined whether the cell 11 can be used or whether the cell 11 cannot be used due to deterioration.

  Further, in this example, with reference to the map shown in FIG. 8, the remaining capacity corresponding to the thickness of the cell 11 measured by the battery thickness measuring unit 21 is calculated on the map, and the remaining capacity calculated on the map is calculated. And the remaining capacity measured by the remaining capacity measuring unit 23, the state of the cell 11 is detected. By using a map indicating the linearity of the thickness of the cell 11 and the remaining capacity measured in advance using a normal battery, the factor of the thickness that changes according to the remaining capacity of the cell is separated. The state of the cell 11 can be detected. Further, in this example, the state of the cell 11 is detected after determining whether it is in a deteriorated state assumed by normal use of the cell 11 or a defective state due to a specific internal abnormality of the battery such as gas generation. be able to.

  Further, in this example, whether the remaining capacity (Qa) calculated by the remaining capacity measuring unit 23 is within the allowable range by comparing the difference (Qa−Qb) of the remaining capacity with the second determination threshold value. If the remaining capacity (Qa) is outside the allowable range, it is determined that the battery state of the cell 11 is in a defective state. Thereby, since the battery state can be detected based on the cause of the change in thickness generated in a normal cell, the detection accuracy can be improved.

  In this example, a flat battery is used for the cell 11. Thereby, since the cell 11 is easy to expand with respect to the normal line direction of the main surface of the cell 11, and the sensor 15 is easy to detect the form change of the cell 11, the detection accuracy of a battery state can be improved.

  In this example, the thickness of the cell 11 is measured, and the battery shape is detected based on the measured thickness. However, the battery state may be detected based on the volume of gas in the cell 11. . When the battery state is detected based on the gas volume in the cell 11, the thickness of the cell 11 may be replaced with the gas volume in the cell 11 in the control of the battery state detection unit 22. That is, in this example, a thin laminate battery is used, and when the cell 11 is expanded, it is difficult to expand in the direction along the main surface of the cell 11. Therefore, if the area of the main surface of the cell 11 is multiplied by the thickness when the cell 11 is expanded, the gas volume in the cell 11 can be substantially measured. Or the volume change of the gas in the cell 11 by the increase / decrease in gas can be measured by measuring the variation | change_quantity of the thickness of the cell 11. FIG. Therefore, in the control of the battery state detection unit 22 described above, the battery state of the cell 11 can be detected in the same manner as described above by replacing the thickness of the cell 11 with the volume of gas in the cell 11.

  Further, in this example, the measured value of the remaining capacity of the remaining capacity measuring unit 23 is used in order to further increase the detection accuracy of the battery condition, but the battery condition may be detected without using the remaining capacity. As described above, when a specific abnormality inside the battery such as gas generation or an excessive deterioration abnormality of the battery occurs, the thickness of the cell 11 becomes larger than the thickness of the normal cell 11. Moreover, the thickness of the normal cell 11 is determined in advance by the battery characteristics. Therefore, the battery state detection unit 22 records a determination threshold corresponding to the thickness of the normal cell 11 in advance, and compares the determination threshold with the thickness measured by the battery thickness measurement unit 21. Then, when the thickness measured by the battery thickness measurement unit 21 is larger than the determination threshold, the battery state detection unit 22 determines that the cell 11 is abnormal or is in a transient deterioration state. The battery state is determined as a defective state. Thereby, this example can realize a highly accurate battery state detection system.

  Further, in this example, the thickness of the cell 11 corresponding to the remaining capacity measured by the remaining capacity measuring unit 23 is calculated on the map shown in FIG. 8, and the calculated value and the battery thickness measuring unit 21 are calculated. The battery state may be detected by comparing the measured value (thickness). Moreover, this example compares the allowable range including the thickness (calculated value) of the cell 11 calculated on the map with the thickness of the cell 11 assumed by the battery thickness measuring unit 21, thereby determining the battery state. May be detected.

  Further, in this example, the difference between the remaining capacities (Qa−Qb) and the second determination threshold are compared, but by comparing the remaining capacities (Qa) and the remaining capacities (Qb), the battery state is detected. Also good.

  The cell 11 corresponds to the “battery” of the present invention, the battery thickness measurement unit 21 is the “volume change measurement unit” of the present invention, the battery state detection unit 22 is the “detection unit” of the present invention, and the remaining capacity. The measuring unit 23 corresponds to “remaining capacity measuring means”.

<< Second Embodiment >>
A battery state detection system according to another embodiment of the invention will be described. In this example, the control of a part of the controller unit 2 is different from the first embodiment described above. Since the configuration other than this is the same as that of the first embodiment described above, the description thereof is incorporated as appropriate.

  The controller unit 2 measures the state of charge (SOC) of the cell 11 from the detection voltage of a voltage sensor (not shown) that detects the voltage of the cell 11.

  As a characteristic of the secondary battery, the electrode 11 expands and contracts due to the movement of the active material between the positive and negative electrodes accompanying charging and discharging, so that the cell 11 expands and contracts. Therefore, the thickness of the cell 11 changes due to a factor different from the degree of deterioration.

  In this example, as described above, in order to make the detection condition of the battery state the same with respect to the volume change of the electrode due to charging / discharging, the determination SOC serving as a threshold is set, and the SOC of the cell 11 becomes the determination SOC. When it reaches, it detects the battery status. Thereby, the battery state can be detected after eliminating the cause of expansion and contraction of the cell 11 due to charge and discharge.

  The controller unit 2 measures the SOC of the cell 11 at a predetermined cycle, and compares the measured SOC with the determination SOC. When the measured SOC and the determination SOC are equal, the battery state detection unit 22 is based on the thickness of the cell 11 measured by the battery thickness measurement unit 21 and the remaining capacity measured by the remaining capacity measurement unit 23. Then, the battery state of the cell 11 is detected. In addition, since the detection method of a battery state is the same as that of 1st Embodiment, description is abbreviate | omitted.

  Hereinafter, the control procedure of the controller unit 2 of this example will be described with reference to FIG. In step S21, the controller unit 2 measures the SOC of the cell 11. In step S22, the controller unit 2 compares the measured SOC with a preset determination SOC.

  If the measured SOC is not equal to the determination SOC, the process returns to step S21. On the other hand, when the measured SOC is equal to the determination SOC, the process proceeds to step S23, and the control flow of the battery state detection control is executed after step S23. Note that the control processing from step S23 to step S29 is the same as the control processing from step S11 to step S17 in FIG.

  As described above, in this example, when the SOC of the cell 11 reaches the determination SOC, the battery state detection control is executed. Thereby, this example can exclude the influence of the expansion and contraction of the battery due to charging / discharging of the cell 11, accurately measure the thickness of the battery, and grasp the battery state.

<< Third Embodiment >>
FIG. 12 is a cross-sectional view of an assembled battery 1 of a battery state detection system according to another embodiment of the invention. This example differs from the first embodiment described above in the sensor configuration and the control of a part of the controller 2. Other configurations are the same as those of the first embodiment described above, and the descriptions of the first and second embodiments are incorporated as appropriate. FIG. 12 is an enlarged view of a portion where the sensors 18 and 19 are provided.

  The protruding portions 131 provided on the upper and lower main surfaces of the case 13 have a flat portion 131a and an inclined portion 131b. The flat part 131 a is a plate-like member along a plane perpendicular to the stacking direction of the cells 11. The inclined portion 131b is a plate-like member that is inclined with respect to a plane perpendicular to the stacking direction.

  The flat part 132 is formed in the outer peripheral part of the main surface where the protrusion part 131 is not provided among the upper and lower main surfaces of the case 13. The flat part 132 is in contact with the restraint plate 14. Further, the flat portion 131 a and the flat portion 132 have different heights in the stacking direction of the cells 11. The inclined portion 131b connects one end of the flat portion 131a and one end of the flat portion 132.

  The sensor 18 is a sensor for detecting the displacement of the cell 11 and is provided in the protruding portion 131. Specifically, the sensor 18 is provided between the constraining plate 14 and the flat portion 131a in a space formed by the protruding portion 131 and between the constraining plate 14 and the surface of the case 13.

  The sensor 19 is a sensor for detecting the displacement of the cell 11 and is provided in a portion of the case 13 other than the protruding portion 131. Specifically, the sensor 19 is formed by the protrusion 131 in a space between the surface of the case 13 and the main surface of the cell 11 (an opposing surface facing the flat portion 132 of the case 13). It is provided between the cells 11.

  The sensors 18 and 19 are covered with an elastic material such as rubber so that they are easily expanded and contracted by the displacement of the cell 11. The sensors 18 and 19 are formed in a cylindrical shape and have strain gauges on the surface. The sensors 18 and 19 detect the displacement by measuring the distance between the upper and lower surfaces of the columnar shape. Detection values of the sensors 18 and 19 are output to the battery thickness measurement unit 21.

  Next, the relationship between the battery state of the cell 11 and the displacement of the cell 11 will be described with reference to FIG. FIG. 13 is a cross-sectional view of a part of the assembled battery 1 similar to that in FIG. Shows an expanded state.

  As factors of the expansion of the cell 11, there are expansion due to deterioration of the battery and expansion due to generation of gas. Further, the expansion of the cell 11 may be caused by one of the factors or may be caused by both factors. As shown in FIG. 13, when expansion occurs in the cell 11, the cell 11 is deformed into a different shape depending on the cause of the expansion.

  When the cell 11 expands due to battery deterioration, the cell 11 expands mainly due to expansion due to electrode deterioration. And the electrode of the cell 11 is formed with the electrode plate along the main surface of the cell 11, as shown in FIG. Therefore, the thickness increases almost uniformly over the entire main surface of the cell 11.

That is, as shown in FIG. 13A, the entire main surface of the cell 11 is pushed up toward the restraint plate 14. At this time, the displacement (Δd ₁ ) of the portion of the cell 11 in contact with the protruding portion 131 is not significantly different from the displacement (Δd ₂ ) of the portion facing the flat portion 132. Therefore, the displacement difference (Δd ₂ −Δd ₁ ) between the displacement (Δd ₁ ) detected by the sensor 18 and the displacement (Δd ₂ ) detected by the sensor 19 becomes a small value.

  On the other hand, when the cell 11 expands due to the generation of gas, the gas collects in a portion of the inside of the cell 11 that is not pressed by the protruding portion 131 and that faces the flat portion 132. And since the space is formed between the case 13 and the portion of the cell 11 facing the flat portion 132, this portion expands greatly. On the other hand, gas does not collect in the portion that contacts the protruding portion 131 and receives stress due to the protruding portion 131, so that the expansion of this portion is reduced.

That is, as shown in FIG. 13B, the portion that is not in contact with the protruding portion 131 is pushed up toward the restraining plate 14. At this time, the displacement (Δd ₂ ) of the portion facing the flat portion 132 rises more than the displacement (Δd ₁ ) of the portion in contact with the protruding portion 131. Therefore, the displacement difference (Δd ₂ −Δd ₁ ) between the displacement (Δd ₁ ) detected by the sensor 18 and the displacement (Δd ₂ ) detected by the sensor 18 is larger than the displacement difference in the case of FIG. , Big value.

In this example, by taking the difference between the detection value of the sensor 18 and the detection value of the sensor 19, the displacement (Δd ₁ ) of the cell 11 in the portion that contacts the protruding portion 131 and the portion of the portion that does not contact the protruding portion 131. It is detected from the displacement difference from the displacement (Δd ₂ ) of the cell 11 whether or not the cell 11 is in a defective state due to gas generation.

The battery thickness measurement unit 21 calculates the difference between the detection value of the sensor 18 and the detection value of the sensor 19, so that the thickness of the portion of the cell 11 that comes into contact with the protruding portion 131 and the protruding portion 131 do not contact. A displacement difference (Δd ₂ −Δd ₁ ) in the thickness of the part is calculated and output to the battery state detection unit 22.

As described above, the displacement difference (Δd ₂ −Δd ₁ ) varies depending on the amount of gas generated. Therefore, when the battery thickness measurement unit 21 calculates the displacement difference (Δd ₂ −Δd ₁ ) from the detection values of the sensors 18 and 19, it also measures the volume of the gas (gas) in the cell 11. . Further, the battery thickness measuring unit 21 calculates the change amount of the displacement difference (Δd ₂ −Δd ₁ ) by calculating the displacement difference (Δd ₂ −Δd ₁ ) in time series. When the gas volume changes in the cell 11, the displacement difference (Δd ₂ −Δd ₁ ) also changes. Therefore, when the battery thickness measurement unit 21 measures the change of the displacement difference (Δd ₂ −Δd ₁ ) from the detection values of the sensors 18 and 19, it also measures the volume change of the gas in the cell 11. .

  The battery state detection unit 22 is preset with a third determination threshold value for determining a defective state of the battery due to gas generation. The third determination threshold is a value set according to the shape of the cell 11 when gas is generated.

Then, the battery state detection unit 22 compares the displacement difference (Δd ₂ −Δd ₁ ) measured by the battery thickness measurement unit 21 with the third determination threshold value. When the displacement difference (Δd ₂ −Δd ₁ ) is larger than the third determination threshold, the battery state detection unit 22 determines the battery state of the cell 11 as a defective state due to gas generation. On the other hand, when the displacement difference (Δd ₂ −Δd ₁ ) is smaller than the third determination threshold, the battery state detection unit 22 determines the battery state of the cell 11 as a normal state.

  Next, the control procedure of the controller unit 2 will be described with reference to FIG. FIG. 14 is a flowchart showing a control procedure of the controller unit 2. The control unit 2 repeatedly performs the following control procedure at a predetermined cycle.

In step S < _b > 31, the battery thickness measurement unit 21 measures the displacement (Δd ₁ , Δd ₂ ) of the cell 11 from the detection values of the sensors 18 and 19. In step S <b> 32, the battery thickness measurement unit 21 calculates a displacement difference (Δd ₂ −Δd ₁ ) and outputs it to the battery state detection unit 22. In addition, the battery state detection unit 22 compares the displacement difference (Δd ₂ −Δd ₁ ) with the third determination threshold value.

When the displacement difference (Δd ₂ −Δd ₁ ) is equal to or smaller than the third determination threshold value, in step S33, the battery state detection unit 22 determines the battery state of the cell 11 as a normal state, and this example End control. On the other hand, when the displacement difference (Δd ₂ −Δd ₁ ) is larger than the third determination threshold value, in step S34, the battery state detection unit 22 determines the battery state of the cell 11 as a defective state due to gas generation, The control of this example is terminated.

  As described above, in this example, the inside of the cell 11 is calculated based on the detection value of the sensor 18 provided in the protrusion 131 of the case 13 and the detection value of the sensor 19 provided in a portion of the case 13 other than the protrusion 131. Measure the volume change of gas. When gas is generated, the portion pressed by the protrusion 131 does not expand, and the portion not pressed by the protrusion 131 expands. In this example, when the gas is generated, the sensors 18 and 19 are provided in the portion that easily expands and the portion that does not easily expand, respectively, so that the measurement accuracy of the gas generated in the cell 11 can be improved.

Further, in this example, the volume change in the cell 11 is measured based on the difference between the detection values of the sensors 18 and 19, and the measured volume change (corresponding to the displacement difference (Δd ₂ −Δd ₁ )) is the third determination. When it is larger than the threshold value, it is determined that the cell 11 is in an abnormal state due to gas generation. Thereby, it is possible to detect that gas is generated in the cell 11 after separating the expansion factor due to battery deterioration.

  The sensor 18 corresponds to the “first sensor” of the present invention, and the sensor 19 corresponds to the “second sensor” of the present invention.

<< 4th Embodiment >>
A battery state detection system according to another embodiment of the invention will be described. In this example, the control of a part of the controller unit 2 is different from the third embodiment described above. Since the other configuration is the same as that of the third embodiment described above, the description thereof is incorporated as appropriate.

In the third embodiment, when the displacement difference (Δd ₂ −Δd ₁ ) is equal to or smaller than the third determination threshold value, the battery state of the cell 11 is determined as a normal state in step S33. Furthermore, it is determined whether or not the battery state of the cell 11 is a defective state due to excessive deterioration.

  The battery state detection unit 22 stores in advance a map showing the correlation between the remaining capacity of the cell 11 and the displacement of the cell 11 shown in FIG. FIG. 15 is a graph showing the relationship between the remaining capacity of the cell 11 and the displacement.

  As shown in graph A of FIG. 15, there is a correlation between the displacement of the normal cell 11 and the remaining capacity, and the displacement of the cell 11 increases as the remaining capacity of the cell 11 decreases. Since the displacement of the cell 11 corresponds to the thickness of the cell 11, the correlation shown in FIG. 15 corresponds to the correlation shown in FIG.

  Moreover, the battery state detection part 22 has prescribed | regulated the range of the displacement of the cell 11 permitted with respect to a certain remaining capacity on a map. A range indicated by a region 1 in FIG. 15 is an allowable range of displacement. The relationship between the thickness of the cell 11 and the remaining capacity ideally shows the characteristics on the graph A, but due to the deterioration of the cell 11 over time, there is some variation with respect to the graph A even with a normal battery. Therefore, in this example, the region 1 is set on the map as an allowable range indicating a normal deterioration range.

  On the other hand, when the deterioration of the cell 11 is excessively advanced, or when some abnormality occurs in the cell 11, the displacement of the cell 11 with respect to the remaining capacity is the value of the region 2 or the region 3 outside the region 1. Become.

  The battery state detection unit 22 calculates the displacement of the cell 11 corresponding to the remaining capacity (Qa) measured by the remaining capacity measurement unit 23 on the map shown in FIG. The battery state detection unit 22 includes the detection value detected by the sensor 18, that is, the displacement of the cell 11 in contact with the protruding portion 31, and the remaining capacity (Qa), and the allowable range shown on the map of FIG. Compare with region 1).

When the displacement of the cell 11 is within the allowable range, the battery state detection unit 22 determines the battery state of the cell 11 as a normal state. On the other hand, when the displacement of the cell 11 is outside the allowable range, the displacement (Δd ₂ −Δd ₁ ) is smaller than the third determination threshold value, but indicates that the entire cell 11 is expanded. Therefore, the battery state detection unit 22 determines that an abnormality has occurred in the battery due to a cause other than gas generation, and determines the battery state of the cell 11 as a defective state.

  Next, the control procedure of the controller unit 2 will be described with reference to FIG. FIG. 16 is a flowchart showing a control procedure of the controller unit 2. The control unit 2 repeatedly performs the following control procedure at a predetermined cycle.

  The control processes in steps S41 and S42 are the same as the control processes in steps S31 and S32 in FIG.

If the displacement difference (Δd ₂ −Δd ₁ ) is equal to or smaller than the third determination threshold value, the remaining capacity measuring unit 23 measures the remaining capacity (Qa) of the cell 11 in step S43. In step S44, the battery state detection unit 22 calculates the displacement of the cell 11 corresponding to the remaining capacity (Qa) on the map of FIG. Moreover, the battery state detection part 22 sets the tolerance | permissible_range including the displacement calculated on the map.

In step S45, the battery state detection unit 22 compares the displacement (Δd ₁ ) of the cell 11 based on the detection value of the sensor 18 with an allowable range. If the displacement (Δd ₁ ) of the cell 11 is within the allowable range, in step S46, the battery state detection unit 22 determines the battery state of the cell 11 as a normal state, and ends the control of this example. To do. On the other hand, if the displacement (Δd ₁ ) of the cell 11 is outside the allowable range, the battery state detection unit 22 determines the battery state of the cell 11 as a defective state in step S47, and ends the control of this example. To do.

As described above, in this example, when the displacement difference (Δd ₂ −Δd ₁ ) is smaller than the third determination threshold value, the displacement of the battery on the map is calculated by referring to the map shown in FIG. The state of the cell 11 is detected by comparing the displacement of the cell 11 with the displacement of the cell 11 detected by the sensor 18. Thereby, the defective state of the battery due to gas generation and the defective state of the battery due to a cause other than gas generation can be distinguished and detected, and as a result, the detection accuracy of the battery state can be improved.

  Further, in this example, when the displacement of the cell 11 detected by the sensor 18 is outside the allowable range indicated on the map, the battery state of the cell 11 is determined as a defective battery state due to a cause other than gas generation. Detect. Thereby, since the battery state can be detected based on the cause of the displacement of the cell 11 that occurs in a normal cell, the detection accuracy can be increased.

  Further, in this example, the remaining capacity of the cell 11 corresponding to the displacement detected by the sensor 18 is calculated on the map shown in FIG. 15, and the calculated value and the remaining capacity measured by the remaining capacity measuring unit 23 are calculated. The battery state may be determined by comparing. In this example, the battery state may be detected by comparing the allowable range including the remaining capacity (calculated value) calculated on the map and the remaining capacity of the remaining capacity measuring unit 23.

<< 5th Embodiment >>
FIG. 17 is a block diagram of a battery state detection system according to another embodiment of the invention. This example is different from the above-described first embodiment in that the gas volume in the cell 11 is measured from the position where the sensor 31 is provided and the contact area between the cell 11 and the sensor 31. Other configurations are the same as those of the first embodiment described above, and the descriptions of the first to fourth embodiments are incorporated as appropriate.

  The controller unit 2, which is one of the configurations of the battery state detection system of the present example, includes a battery state detection unit 22, a remaining capacity measurement unit 23, and a volume measurement unit 24. The volume measuring unit 24 measures the volume of gas in the cell 11 from the detection value of the sensor 31 provided in the assembled battery 1. For example, a pressure sensor is used as the sensor 31.

  The installation position of the sensor 31 is demonstrated using FIG.18 and FIG.19. FIG. 18 is a cross-sectional view of the battery module 10, and FIG. 19 is an enlarged cross-sectional view of the sensor 31 in the cross-sectional view of FIG.

  Similar to the case 13 shown in FIG. 12, the case 13 of this example has a protruding portion 131 formed of a flat portion 131 a and an inclined portion 131 b. In addition, since the structure of the flat part 131a of this example, the inclination part 131b, and the flat part 132 is the same as that of the flat part 131a which concerns on 3rd Embodiment, the inclination part 131b, and the flat part 132, description is abbreviate | omitted.

  The sensor 31 is provided on the inclined portion 131 so as to face the main surface of the cell 11. In addition, the sensor 31 is provided along the surface facing the cell 11 side of both surfaces of the inclined portion 131.

  When the cell 11 is not expanded, the main surface of the cell 11 is not in contact with the sensor 31. On the other hand, when the cell 11 is expanded, a portion of the main surface of the cell 11 that is not in contact with the flat portion 131a expands toward the case 13, and the main surface of the cell 11 and the sensor 31 come into contact with each other.

  A contact portion between the cell 11 and the sensor 31 will be described with reference to FIGS. 20 and 21 are plan views of the cell 11 for explaining a contact portion between the cell 11 and the sensor 31. FIG. FIG. 20 shows the state of the cell 11 at the normal time, and FIG. 21 shows the state of the cell 11 at the time of cell expansion. 20 and 21, a region 11 a indicates a portion of the main surface of the cell 11 that is in contact with the flat portion 131 a, a region 11 b indicates a portion facing the inclined portion 131 b, and a region 11 c indicates a flat portion 132. The part which opposes is shown (refer FIG. 19). Moreover, the part which contacts the sensor 13 among the area | regions 11b is shown by the area | region 11d.

  When the cell 11 is normal and not expanded, the region 11b does not come into contact with the sensor 11, so that the region 11d does not exist as shown in FIG. On the other hand, when the cell 11 expands, the region 11 b is pushed up toward the sensor 31, and the region 11 b comes into contact with the sensor 31. Therefore, as shown in FIG. 21, a contact portion appears like a region 11d.

  The volume measuring unit 24 measures the volume of the gas in the cell 11 based on the detection value of the sensor 31. A method for measuring the volume of gas by the volume measuring unit 24 will be described with reference to FIG. Assume that cell 11 has expanded, as shown at P in FIG.

  As shown in FIG. 19, the contact width (x) where the cell 11 and the sensor 31 are in contact with each other corresponds to the volume increase region (P) of the cell 11. The contact width (x) is equivalent to the contact area between the cell 11 and the sensor 31.

  When gas is generated in the cell 11, the larger the entire volume in the cell 11, the larger the displacement of the cell 11 due to the expansion of the cell 11, and the larger the contact area. The correlation between the cell displacement and the contact area due to cell expansion is derived at the design stage if the battery characteristics of the cell 11, the shapes of the cell 11 and the case 31, and the installation position of the sensor 31 are determined. That is, the contact area between the cell 11 and the sensor 31 indicated by the region 11 has a correlation with the volume of the gas in the cell 11 (the volume of the increase indicated by P in FIG. 19).

  In the volume measuring unit 24, a map indicating the correlation between the contact area between the cell 11 and the sensor 31 and the volume of the gas in the cell 11 is recorded in advance. The volume measuring unit 24 calculates the contact area from the contact width (x) that is a detection value of the sensor 31. Then, the volume measuring unit 24 refers to the map and measures the volume corresponding to the calculated contact area as the gas volume in the cell 11. When the case 13 is distorted in the stacking direction of the cells 11 due to the expansion of the cells 11, the volume measuring unit 24 may measure the volume by entering a correction term according to the amount of distortion.

  The battery state detection unit 22 sets an allowable range of the volume of the gas in the cell 11 from the remaining capacity of the cell 11 measured by the remaining capacity measurement unit 23. In the first embodiment, the correlation between the thickness of the cell 11 and the remaining capacity of the cell 11 is shown using FIG. 8, but the same is true between the volume of gas in the cell 11 and the remaining capacity of the cell 11. There is a correlation.

  In the battery state detection unit 22, a map indicating the correlation between the gas volume in the cell 11 and the remaining capacity of the cell 11 is recorded in advance. Then, the battery state detection unit 22 refers to the map and calculates the gas volume corresponding to the remaining capacity measured by the remaining capacity measurement unit 23.

  Furthermore, the battery state detection part 22 sets the inside of the predetermined range centering on the volume of the gas calculated on the map as a volume allowable range. Even when the cell 11 is in a normal state, the volume of the gas in the cell relative to the remaining capacity may differ from the value indicated by the correlation due to the deterioration of the cell 11. Therefore, in this example, the allowable range is set in consideration of the deterioration of the normal cell 11.

  Then, the battery state detection unit 22 compares the gas volume measured by the volume measurement unit 24 with the allowable range. When the measured gas volume is outside the allowable range, the battery state detection unit 22 detects the battery state of the cell 11 as a defective state. On the other hand, when the measured gas volume is within the allowable range, the battery state detection unit 22 detects the battery state of the cell 11 as a normal state.

  Next, the control procedure of the controller unit 2 will be described with reference to FIG. FIG. 22 is a flowchart showing the control procedure of the controller unit 2. The control unit 2 repeatedly performs the following control procedure at a predetermined cycle.

  In step S <b> 51, the volume measuring unit 24 measures the contact area between the sensor 31 and the cell 11 from the detection value of the sensor 31. In step S <b> 52, the volume measuring unit 24 measures the volume of the gas in the cell 11 with reference to a map indicating the correlation between the contact area and the volume of the gas.

  In step S53, the remaining capacity measuring unit 23 measures the remaining capacity of the cell 11. In step S <b> 54, the battery state detection unit 22 sets an allowable range of the gas volume based on the remaining capacity measured by the remaining capacity measurement unit 23. In step S <b> 55, the battery state detection unit 22 compares the gas volume measured by the volume measurement unit 24 with the allowable range.

  If the measured gas volume is within the allowable range, in step S56, the remaining capacity measuring unit 23 detects the battery state of the cell 11 as a normal state, and ends the control of this example. On the other hand, if the measured gas volume is outside the allowable range, in step S57, the remaining capacity measuring unit 23 detects the battery state of the cell 11 as a defective state, and ends the control of this example. .

  As described above, in this example, the sensor 31 is provided in the inclined portion 131b, and the volume of the gas in the cell 11 is calculated from the detection value of the sensor 31. Thereby, since the form of the cell 11 can be grasped | ascertained, the volume in the cell 11 can be measured accurately.

  Further, in this example, in the stacking direction of the cells 11, the flat portion 131 a and the flat portion 132 having different heights are provided on the main surface of the case 13, and the inclined portion 131 b is provided between the flat portion 131 a and the flat portion 132. The sensor 31 is provided on the inclined portion 131b. As a result, the space in which the cell 11 expands due to the generation of gas is formed between the inclined portion 131b, the flat portion 132, and the cell 11, and the sensor 31 is provided in the inclined portion 131b where the cell easily expands. The volume in the cell 11 can be measured with high accuracy.

  In this example, a flat portion 131a is provided at a position closer to the cell 11 than the flat portion 132 in the stacking direction, and the flat portion 131a and the cell 11 are brought into contact with each other. Thereby, at the time of gas generation, it is possible to distinguish between the portion that expands and the portion that does not easily expand, and the sensor 131 can be provided in the portion that expands, so that the volume in the cell 11 can be measured with high accuracy.

  The volume measuring unit 24 corresponds to the “volume change measuring unit” of the present invention, and the sensor 31 corresponds to the “third sensor” of the present invention.

DESCRIPTION OF SYMBOLS 1 ... Assembly battery 10 ... Battery module 11 ... Cell 111 ... Exterior member 111a ... Inner resin layer 111b ... Intermediate metal layer 111c ... Outer resin layer 112 ... Power generation element 112a ... Positive electrode plate 112b ... Negative electrode plate 112c ... Separator 112d ... Positive electrode side collection Electrodes 112e, 112f ... Positive electrode layer 112g ... Negative electrode side current collector 112h, 112i ... Negative electrode layer 113 ... Outer peripheral part 114 ... Positive electrode terminal 115 ... Negative electrode terminal 120 ... Spacer 121 ... Fixing part 13 ... Case 131 ... Projection part 131a ... Flat Part 131b ... Inclined part 132 ... Flat part 14 ... Restraint plate 15, 18, 19, 31 ... Sensor 16 ... Bolt 17 ... Nut 2 ... Controller unit 21 ... Battery thickness measurement part 22 ... Battery state detection part 23 ... Remaining capacity measurement Part 24: Volume measuring part

Claims (15)

In the internal space formed by sealing with the exterior member, a battery that houses the power generation element,
Volume change measuring means for measuring the volume change of the gas in the internal space;
A battery state detection system comprising: detection means for detecting the state of the battery from the volume change measured by the volume change measurement means. The battery state detection system according to claim 1,
The detection means includes
A battery state detection, wherein a deterioration state of the battery is detected by comparing a deterioration determination threshold corresponding to a lower limit value of the remaining capacity of the battery and a volume of the gas measured by the volume change measuring unit. system. The battery state detection system according to claim 1 or 2,
Further comprising a remaining capacity measuring means for measuring the remaining capacity of the battery,
The detection means includes
With reference to a map showing the correlation between the volume of the gas and the remaining capacity, the volume of the gas or the remaining capacity on the map is calculated as a calculated value,
A battery state detection system that detects the state of the battery by comparing the measured value measured by the volume change measuring unit or the measured value measured by the remaining capacity measuring unit with the calculated value. The battery state detection system according to any one of claims 1 to 3,
A case containing the battery and having a protrusion protruding from the outside toward the battery;
A first sensor provided on the projecting portion for detecting displacement of the battery;
A second sensor that is provided in a portion of the case other than the protruding portion and detects a displacement of the battery;
The volume change measuring means includes
The battery state detection system, wherein the volume change is measured from a detection value of the first sensor and a detection value of the second sensor. The battery state detection system according to claim 4,
The volume change measuring means includes
Measuring the volume change by the difference between the detection value of the first sensor and the detection value of the second sensor;
The detection means includes
A battery state detection system that determines that the battery is in a defective state when the volume change corresponding to the difference is greater than a predetermined threshold. The battery state detection system according to claim 5,
Further comprising a remaining capacity measuring means for measuring the remaining capacity of the battery,
The detection means includes
When the volume change corresponding to the difference is smaller than a predetermined threshold, a map showing the correlation between the displacement of the battery and the remaining capacity is referred to, and the displacement of the battery or the remaining capacity on the map As a computed value,
A battery state detection system that detects the state of the battery by comparing the calculated value with the displacement of the battery detected by the first sensor or the measured value measured by the remaining capacity measuring means. The battery state detection system according to claim 3 or 6,
The detection means includes
When the measured value is outside a predetermined allowable range including the calculated value, it is determined that the battery is in a defective state. The battery state detection system according to claim 6,
The detection means includes
A battery state detection system that determines that the battery is in a defective state when the displacement of the battery is outside a predetermined allowable range including the calculated value. The battery state detection system according to any one of claims 1 to 3,
A case for housing the battery;
A third sensor,
The case is
The surface of the case has an inclined portion that is inclined with respect to a plane perpendicular to the stacking direction of the electrode plates included in the battery,
The third sensor is provided in the inclined portion, detects displacement of the battery,
The volume change measuring means includes
The battery state detection system, wherein the gas volume is measured from a detection value of the third sensor. The battery state detection system according to claim 9,
The case is
A first flat portion and a second flat portion that are flat along the vertical plane and have different heights in the stacking direction on the surface of the case;
The battery state detection system, wherein the inclined part is located between the first flat part and the second flat part. The battery state detection system according to claim 10,
The battery state detection system, wherein the first flat portion is positioned closer to the battery than the second flat portion in the stacking direction, and is in contact with the battery. In the battery state detection system according to any one of claims 9 to 11,
The volume change measuring means includes
Calculating a contact area between the inclined portion and the exterior member from the third detection value, and measuring the volume change from the contact area;
A battery state detection system characterized by that. In the detection method of detecting the battery state of the battery that houses the power generation element in the internal space formed by sealing with the exterior member,
A volume change measuring step for measuring a volume change of the gas in the internal space;
And a detecting step of detecting the battery state from the volume change measured by the volume change measuring step. The battery state detection method according to claim 13,
The volume change measuring step includes
Provided in a protrusion that protrudes from the outside of the case housing the battery toward the battery, the detection value of the first sensor that detects the displacement of the battery, and provided in the case other than the protrusion, A battery state detection method comprising measuring a volume change of the gas from a detection value of a second sensor for detecting displacement of the battery. The battery state detection method according to claim 13,
The volume change measuring step includes
A detection value of a third sensor that is provided on a surface of a case housing the battery and is inclined with respect to a surface perpendicular to a stacking direction of electrode plates included in the battery, and detects displacement of the battery. A battery state detection method comprising measuring the volume of the gas.

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