JP2015099087A - Temperature sensor and contact determination method for temperature sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a temperature sensor capable of determining a contact state and a contact determination method for the temperature sensor.SOLUTION: In a thermistor 32, a lower surface 32a of the thermistor 32 contacts a cover plate 23 of a battery cell. An electric resistance between the lower surface 32a and the cover plate 23 of the battery cell is obtained by measuring an electric resistance between an upper surface 32b and the cover plate 23 of the battery cell (P1-P2 electric resistance, for example). According to the thermistor 32, therefore, it is possible to determine a contact state in which the thermistor 32 contacts the battery cell on the basis of the measured electric resistance.

Description

  The present invention relates to a temperature sensor that detects a temperature change of a battery cell and a method for determining contact thereof.

  2. Description of the Related Art Conventionally, as a power supply device, a power supply device including a plurality of battery cells is known in order to ensure a high voltage and high output power supply.

  A temperature sensor is used in the power supply device for the purpose of detecting an abnormally high temperature state of the battery cell. Such a temperature sensor cannot detect or detects erroneous information unless there is sufficient contact with the battery cell that is the detection target. Therefore, in Patent Document 1 below, a thermistor thermometer is used as a temperature sensor to be assembled to the battery cell, and the thermistor thermometer is biased toward the battery cell, whereby contact between the thermistor thermometer and the battery cell is achieved. A technique for improving the above is disclosed.

JP 2006-186045 A

  However, as in the conventional thermistor thermometer described above, even if the thermistor thermometer is biased toward the battery cell, the thermistor thermometer is tilted, or foreign matter enters between the thermistor thermometer and the battery cell. In practice, sufficient contact may not be obtained with the battery cell. Therefore, a technique that can determine the contact state of the temperature sensor is required.

  That is, an object of the present invention is to provide a temperature sensor capable of determining a contact state and a method for determining the contact.

  A temperature sensor according to one embodiment of the present invention is a temperature sensor attached to a battery unit having battery cells, and has a conductive surface having conductivity on an outer surface, and the conductive surface has conductivity in the battery unit. A contact portion that is in direct contact with the included portion or indirectly through a conductive member, and a measurement portion that is electrically connected to the contact portion and exposed to the outside in a state where the temperature sensor is attached to the battery unit.

  In the temperature sensor, the contact portion of the conductive surface is in contact with the conductive portion of the battery unit. The electrical resistance between the contact portion of the conductive surface and the conductive portion of the battery unit can be obtained by measuring the electrical resistance between the measurement portion of the conductive surface and the conductive portion of the battery unit. And the contact state of the temperature sensor with respect to a battery unit can be determined based on the electrical resistance.

  In addition, the sensor body may include a non-conductive sensor body and a conductive covering portion that covers at least a part of the outer surface of the sensor body, and the contact portion and the measurement portion may be provided on the covering portion. Good. When the sensor body is non-conductive, a conductive surface can be provided on the outer surface of the temperature sensor using a conductive covering.

  Moreover, the aspect which is a metal case in which a coating | coated part accommodates a sensor main body may be sufficient. In this case, conductivity can be imparted to the surface of the temperature sensor, and the rigidity of the temperature sensor can be increased.

  Moreover, the aspect which is an electroconductive film which covers a sensor main body may be sufficient. In this case, conductivity can be imparted to the surface of the temperature sensor, and the covering portion can be easily thinned.

  Further, the conductive member may be a conductive adhesive, and the conductive part may be bonded to the contact portion and the conductive part in the battery unit. The temperature sensor may be held or energized. In this case, the adhesiveness between the temperature sensor and the conductive part in the battery unit is improved, and the positional deviation between the temperature sensor and the conductive part in the battery unit is suppressed.

  Moreover, the aspect which is a part which has the electroconductivity in a battery cell may be sufficient as the part which has the electroconductivity in a battery unit. In this case, since the temperature sensor directly detects the temperature of the battery cell, high detection accuracy can be realized.

  Moreover, the aspect which is a part which has the electroconductivity in the attachment member thermally connected with the battery cell may be sufficient as the part which has electroconductivity in a battery unit. In this case, the temperature sensor detects the temperature of the attached member, thereby indirectly detecting the temperature of the battery cell. Therefore, even if it is a structure where it is difficult to attach the temperature sensor directly to the battery cell, the temperature of the battery cell can be detected.

  The temperature sensor contact determination method according to one aspect of the present invention includes a temperature sensor having a conductive contact portion and a measurement portion that are electrically connected to each other on the outer surface, and the contact portion has conductivity in the battery unit. Between the attachment step attached to the battery unit so as to be in contact with the part having, the measurement part of the temperature sensor, and the conductive part electrically connected to the part to which the temperature sensor is attached in the battery unit. A measurement step of measuring resistance, and a determination step of determining a state of contact between the temperature sensor and the battery unit based on the electrical resistance measured in the measurement step.

  In the method for determining contact of the temperature sensor, in the attachment step, the temperature sensor is attached to the battery unit so that the contact portion is in contact with the conductive portion of the battery unit. In the measurement step, the electrical resistance between the contact portion and the conductive portion of the battery unit is measured by measuring the electrical resistance between the conductive portion of the battery unit and the measurement portion of the temperature sensor. Is obtained. In the determination step, the contact state of the temperature sensor with respect to the battery unit is determined based on the electrical resistance measured in the measurement step.

  ADVANTAGE OF THE INVENTION According to this invention, the temperature sensor which can determine a contact state, and the determination method of the contact are provided.

FIG. 1 is a schematic perspective view illustrating a power supply device according to an aspect of the present invention. FIG. 2 is a top plan view of the power supply device of FIG. FIG. 3 is an exploded perspective view of the battery unit. FIG. 4 is a diagram showing an installation mode of the temperature sensor. FIG. 5 is an enlarged view of a main part of the power supply device of FIG. FIG. 6 is a flowchart showing a procedure for determining contact of the temperature sensor. FIG. 7 is a diagram showing an aspect in which (a) a conductive adhesive is used, and (b) an aspect in which it is urged by a lid.

  Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the accompanying drawings. In addition, the same code | symbol is attached | subjected about the same or equivalent element, and the description is abbreviate | omitted when description overlaps.

  First, the power supply device 1 will be described with reference to FIGS. 1, 2, and 3.

  As shown in FIG. 1, the power supply device 1 includes a battery module 10 and a lid 12 attached to the upper side of the battery module 10.

  The battery module 10 has a plurality (seven in the figure) of battery units 14 arranged in parallel. Further, the battery module 10 has a pair of end plates 16 at both ends of the battery unit 14 in the juxtaposition direction, and the plurality of battery units 14 are restrained by the pair of end plates 16. For example, four bolts 19A to 19D that are inserted into one end plate 16 and extend in the direction of the other end plate 16 are inserted into each battery unit 14 and the other end plate 16. The other end plate 16 is fixed by being screwed to the nut. A fixing member 18 is fixed to each end plate 16. Each end plate 16 is made of iron because high rigidity is required.

  As shown in FIG. 2, the battery module 10 is fixed to a wall W extending in the vertical direction so as to be cantilevered via a fixing member 18.

  As shown in FIG. 3, each battery unit 14 includes a battery cell 20, a resin holder 28, and a heat transfer plate 29.

  The battery cell 20 includes a case 21, an electrode assembly (not shown) housed in the case 21, and a pair of terminals 24 joined to the electrode assembly provided in the case 21. The case 21 is made of a conductive material (for example, aluminum), and includes a bottomed rectangular tube-shaped case main body 22 and a cover plate 23 that covers the opening of the case main body 22. The case main body 22 includes a rectangular flat plate-shaped bottom plate 22a and four side surfaces 22b to 22e that stand up from four sides of the bottom plate 22a. Hereinafter, for convenience of description, of the four side surfaces 22b to 22e, two side surfaces intersecting with the direction in which the battery units 14 are arranged are referred to as a first side surface 22b and a second side surface 22c, and the other two side surfaces are referred to as a third side surface 22d. This is referred to as a fourth side surface 22e.

  The pair of terminals 24 are terminals for taking out the electric power of the electrode assembly of the battery cell 20 to the outside. In the present embodiment, as shown in FIG. 2, terminals 24 having different polarities adjacent to each other are connected to each other via a bus bar 25 so as to be connected in series.

  As shown in FIG. 3, the resin holder 28 is a frame body integrally formed of resin, and includes a wiring portion 28 a disposed on the cover plate 23 and a bottom surface portion 28 b facing the bottom plate 22 a of the case main body portion 22. And a pair of upright portions 28c respectively facing the third side surface 22d and the fourth side surface 22e of the case main body 22.

  The wiring portion 28a includes a peripheral wall 29a erected so as to surround each terminal 24, a pair of outer walls 29b extending vertically upward from the pair of erected portions 28c, and the opposite side of the outer wall 29b across the peripheral wall 29a. And a pair of first bolt guide portions 29d provided between the peripheral wall 29a and the partition wall 29c, and a holding portion 30 for holding a thermistor 32 described later.

  The partition wall 29c extends along the direction in which the battery units 14 are arranged side by side. A pair of first bolt guide portions 29d having guide holes 27A and 27B for guiding the bolts 19A and 19B described above are provided on the terminal 24 side of the partition wall 29c. A holding portion 30 is provided on the side of the partition wall 29c opposite to the terminal 24 side to hold a thermistor 32 (described later) so as to contact the lid plate 23 in a posture along the partition wall 29c.

  The resin holder 28 further includes a pair of second bolt guide portions 28d having guide holes 27C and 27D for guiding the bolts 19C and 19D described above, which are defined by the bottom surface portion 28b and the pair of standing portions 28c. Provided at the corner.

  The heat transfer plate 29 is an L-shaped metal plate disposed so as to cover the first side surface 22b and the third side surface 22d of the case body 22, and is made of, for example, aluminum. The heat transfer plate 29 can receive the heat of the battery cell 20 at the portion covering the first side surface 22b and radiate the heat to the wall W from the portion covering the third side surface 22d.

  Since the resin holder 28 described above does not have a portion that covers the first side surface 22 b and the second side surface 22 c of the case body 22, the heat transfer plate 29 is the first of the battery cells 20 held by the resin holder 28. It contacts the side surface 22b.

  In addition, the double-sided adhesive tape 26 is affixed to the 1st side surface 22b and the 2nd side surface 22c of the battery cell 20 on the whole surface except the outer edge area | region. Therefore, the heat transfer plate 29 is bonded to the first side surface 22 b of the battery cell 20 via the double-sided adhesive tape 26. As shown in FIG. 3, since the heat transfer plate 29 of the adjacent battery unit 14 is also present on the second side surface 22 c side of the battery cell 20, the battery cell 20 positioned on both sides in the parallel arrangement direction of the battery units 14. Each battery cell 20 except for is sandwiched between a pair of heat transfer plates 29 via a double-sided adhesive tape 26.

  Here, the thermistor 32 will be described with reference to FIG.

  The thermistor 32 includes a thermistor body (sensor body) 33, a signal line 34 extending from the thermistor body 33, and a case (covering part) 35 that houses the thermistor body 33.

  The thermistor body 33 has a configuration in which an element (not shown) whose electric resistance changes according to temperature is covered with a resin. That is, the surface of the thermistor body 33 is made of resin and is non-conductive. The thermistor body 33 has a rectangular parallelepiped outer shape.

  The signal line 34 is a pair of output lines, one end of which is connected to the element inside the thermistor body 33 and outputs the electric resistance of the element. The other end of the signal line 34 extends outward from one side surface of the thermistor body 33 and is bundled together with other signal lines as the cable 15 of the battery module 10.

  The case 35 is a conductive metal case (for example, an aluminum case), and its outer shape has a rectangular parallelepiped shape like the thermistor body. The internal dimensions of the case 35 are designed according to the external dimensions of the thermistor body 33, and the thermistor body 33 is preferably accommodated in the case 35 without any gaps. The outer surface of the case 35 is the outer surface of the thermistor 32 and is a conductive surface having conductivity.

  The above-described thermistor 32 is installed such that its lower surface 32 a is in contact with the lid plate 23 of the battery cell 20. That is, the lower surface 32a of the thermistor 32 corresponds to a contact portion that comes into contact with the cover plate 23 (that is, a conductive portion in the battery unit 14). More specifically, the lower surface 32 a of the thermistor 32 is installed in the installation region 23 a of the thermistor 32 in the lid plate 23 of the battery cell 20 (corresponding to a portion where the thermistor 32 is attached in the battery unit 14), and directly contacts the lid plate 23. .

  The thermistor 32 is thus installed on the lid plate 23 of the battery cell 20, and the position and posture thereof are held by the holding unit 30 described above as shown in FIG.

  The holding unit 30 is a part that regulates the displacement of the thermistor 32, and the upper surface holding unit 30 a that regulates the movement of the thermistor 32 in the direction away from the lid plate 23 (vertically upward), and the thermistor 32 in the lid plate 23. And a side surface holding portion 30b that restricts movement of the abutting surface on the surface. More specifically, the side surface holding portion 30b is formed in a substantially L shape. The side surface holding portion 30b is disposed on the lid plate 23 in contact with the lid plate 23 so as to be L-shaped when viewed from above. Further, the side surface holding portion 30b is provided so that one end surface thereof is in contact with the partition wall 29c. The upper surface holding portion 30a is formed in a plate shape, and is provided on the surface of the side surface holding portion 30b opposite to the surface in contact with the cover plate 23. Then, the thermistor 32 is inserted into the accommodation space defined by the upper surface holding portion 30a and the side surface holding portion 30b.

  Returning to FIG. 1, the lid 12 is a member that has a substantially U-shaped cross-sectional shape and covers the upper surfaces of all the battery units 14 of the battery module 10. The lid 12 includes a rectangular plate portion 12 a and a pair of wall portions 12 b that are provided upright at both ends in the short direction of the plate portion 12 a and face each other, and the pair of wall portions 12 b are a pair of outer walls of the resin holder 28. The lid 12 is fixed to the battery module 10 by coming into contact with 29b.

  On the lid 12, a control device 13 for performing various controls relating to the battery module is placed. The control device 13 has a terminal input portion 13a to which the connection terminal 17 of the cable 15 of the battery module 10 including the signal line 34 of the thermistor 32 described above is connected. The control device 13 records the electrical resistance of the thermistor 32 input via the signal line 34, and cuts off the current of the battery module 10 when an abnormal electrical resistance is detected.

  The lid 12 is a member also called a bus bar cover. In addition to the role of placing the control device 13 described above, the battery module 10 positioned on the lower side and the battery module 10 positioned on the upper side when the battery modules 10 are stacked. For preventing the gas generated from the battery cell 20 from being blown upward when the battery cell 20 runs away.

  Next, a procedure for determining the contact state of the thermistor 32 with respect to the battery cell 20 in the power supply device 1 described above will be described with reference to FIG.

  When determining the contact state of the thermistor 32 with respect to the battery cell 20, first, the thermistor 32 is attached to the battery unit 14 as attachment step S1. Specifically, the thermistor 32 is disposed on the holding portion 30 of the resin holder 28, and the lower surface (the surface in contact with the battery cell 20) 32 a as a contact portion of the thermistor 32 and the lid plate 23 of the battery cell 20 are brought into contact with each other. In the state, the thermistor 32 is attached to the battery unit 14.

  Next, as the measurement step S2, in the thermistor 32, a portion that is electrically connected to the lower surface 32a and is exposed to the outside when the thermistor 32 is attached to the battery unit 14, and an installation area in the lid plate 23 of the battery cell 20 The electrical resistance between the conductive part electrically connected to 23a is measured. In the present embodiment, the electric resistance between the upper surface (surface opposite to the surface in contact with the battery cell 20) 32b as a measurement unit and the portion other than the installation region 23a in the cover plate 23 of the battery cell 20 is determined. taking measurement. For example, the probe of the resistance measuring instrument is applied to the position of the point P1 on the upper surface 32b of the thermistor 32 and the position of the point P2 in the region other than the installation region 23a of the thermistor 32 in the lid plate 23 of the battery cell 20. The electrical resistance between P1 and P2 is measured.

  Finally, as the determination step S3, the contact state between the thermistor 32 and the battery cell 20 is determined based on the electrical resistance between P1 and P2 measured in the measurement step S2.

  Since both the surface of the thermistor 32 and the lid plate 23 of the battery cell 20 are conductive, the electrical resistance between P1 and P2 is zero or a value close to zero in a good contact state. . On the other hand, when the contact state is not good due to the presence of foreign matter, the electrical resistance between P1 and P2 shows a high value. Therefore, with a certain threshold as a reference, it can be determined that the contact state is good when the electrical resistance is lower than the threshold, and when the electrical resistance is higher than the threshold, the contact is poor. It can be determined that there is.

  As described above, in the thermistor (temperature sensor) 32, the lower surface 32 a of the thermistor 32 is in contact with the lid plate 23 of the battery cell 20. And the electrical resistance between the lower surface 32a and the cover plate 23 of the battery cell 20 measures the electrical resistance (for example, electrical resistance between P1-P2) between the upper surface 32b and the cover plate 23 of the battery cell 20. Can be obtained. Therefore, according to the thermistor 32, the contact state of the thermistor 32 with respect to the battery cell 20 can be determined based on the measured electrical resistance.

  Moreover, since the lower surface 32a contact | abuts the cover plate 23 of the battery cell 20, and the temperature of the thermistor 32 can detect the temperature of the battery cell 20 directly, the high detection precision is implement | achieved.

  The present invention is not limited to the above embodiment, and various modifications are possible.

  For example, the thermistor 32 does not necessarily need to have conductivity on the entire surface, and for example, the lower surface 32a in contact with the battery cell 20 and a portion other than the lower surface 32a may have conductivity. However, the lower surface 32a and a portion other than the lower surface 32a need to be electrically connected. In this case, the measurement point P1 of the electrical resistance is a position in a part having conductivity other than the lower surface 32a.

  Further, instead of the case 35 described above, a conductive film can be employed as a covering portion that covers the thermistor body 33. When the covering portion is a metal case, it is preferable in that the rigidity of the temperature sensor can be increased. Moreover, when a coating | coated part is an electroconductive film, it is preferable at the point which can aim at thinning of a coating | coated part easily.

  In addition, when the surface of a temperature sensor has electroconductivity, it is not necessary to use the metal case and electroconductive film which were mentioned above.

  Further, the thermistor 32 is not limited to the cover plate 23 as long as it is a conductive part in the battery cell 20, and may be attached so as to be in contact with any place.

  Furthermore, the thermistor 32 and the battery cell 20 may be in contact via a conductive member. This is because even if a conductive member is interposed between the thermistor 32 and the battery cell 20, the electric resistance between P1 and P2 described above is not substantially affected. That is, even when a conductive member is interposed between the thermistor 32 and the battery cell 20, the contact state of the thermistor 32 with respect to the battery cell 20 can be determined. Note that setting a threshold value for determining the contact state in consideration of the electrical resistance of the conductive member enables more accurate determination.

  For example, as shown in FIG. 7A, a conductive adhesive 40 can be used as the conductive member. By using the conductive adhesive 40, the adhesion between the lower surface 32 a of the thermistor 32 and the lid plate 23 of the battery cell 20 is improved, and the misalignment between the thermistor 32 and the battery cell 20 is suppressed. Moreover, since the electrical resistance between the lower surface 32a of the thermistor 32 and the cover plate 23 of the battery cell 20 can be reduced by providing the conductive adhesive 40, a more accurate determination can be made. Further, when a conductive member is interposed between the thermistor 32 and the battery cell 20, if a part of the lower surface 32 a of the thermistor 32 is in contact with the conductive member, a portion other than the portion in contact with the conductive member of the lower surface 32 a When the thermistor 32 is attached to the battery unit 14, the battery unit 14 is exposed to the outside, and the probe of the resistance measuring instrument described above can be contacted from the outside. In this case, a portion other than the portion in contact with the conductive member on the lower surface 32a may be used as the measurement unit.

  Further, as shown in FIG. 7B, instead of holding the thermistor 32 by the holding unit 30, the thermistor 32 may be biased against the lid plate 23 of the battery cell 20 using the lid 12 described above. . At this time, an elastic member (for example, rubber or sponge) 42 for raising the volume may be disposed in the gap between the thermistor 32 and the plate portion 12a of the lid 12. Also in this case, the contact property between the thermistor 32 and the battery cell 20 is improved, and the positional deviation between the thermistor 32 and the battery cell 20 is suppressed. In addition, since the thermistor 32 can be held using the lid 12 provided for the purpose of placing the control device 13 or the like, it is not necessary to provide the holding unit 30.

  Furthermore, when measuring the above-described electrical resistance, a lead wire connected to the surface of the thermistor 32 or the lid plate 23 of the battery cell 20 can be used instead of the probe. In this case, the electrical resistance can be measured by the resistance measuring device described above, or the electrical resistance can be measured by the control device 13 by connecting the lead wire to the control device 13 via the cable 15.

  In the above-described embodiment, the thermistor 32 detects the temperature change of the battery cell 20. For example, when the thermistor 32 is difficult to attach directly to the battery cell 20, By detecting the temperature change of the attachment member thermally connected, the temperature of the battery cell 20 can be estimated by indirectly detecting the temperature of the battery cell.

  The attachment member of the battery cell 20 includes the heat transfer plate 29 and the resin holder 28 described above.

  For example, when the heat transfer plate 29 is an attachment member, the thermistor 32 is attached to the heat transfer plate 29, and the contact state between the heat transfer plate 29 and the thermistor 32 can be determined by the same method as described above. .

  When the resin holder 28 is used as an attachment member, the surface of the resin holder 28 is non-conductive. Therefore, when the thermistor 32 is attached to the resin holder 28, a conductive film or the like is attached to a part of the surface of the resin holder 28. Thus, the surface to which the thermistor 32 is attached needs to be conductive. Even in this case, the contact state between the resin holder 28 and the thermistor 32 can be determined by the same method as described above.

  The conductivity of the portion having conductivity in the thermistor 32 and the conductivity of the temperature measurement unit (for example, the cover plate 23 of the battery cell 20) may be different. In this case, it is possible to determine with higher accuracy by setting a threshold value for determining the contact state in consideration of the difference in conductivity.

  DESCRIPTION OF SYMBOLS 1 ... Power supply device, 10 ... Battery module, 12 ... Lid, 20 ... Battery cell, 21 ... Case, 22 ... Case main-body part, 23 ... Cover plate, 30 ... Holding part, 32 ... Thermistor, 32a ... Lower surface, 32b ... Upper surface , 33: Thermistor body, 35: Case, 40: Conductive adhesive.

Claims (9)

A temperature sensor attached to a battery unit having battery cells,
Having an electrically conductive surface on the outer surface,
The conductive surface is
A contact portion that directly or indirectly contacts a conductive portion of the battery unit via a conductive member;
A temperature sensor having a measurement unit that is electrically connected to the contact unit and exposed to the outside in a state where the temperature sensor is attached to the battery unit. A non-conductive sensor body, and a conductive coating covering at least a part of the outer surface of the sensor body,
The temperature sensor according to claim 1, wherein the contact portion and the measurement portion are provided in the covering portion.   The temperature sensor according to claim 2, wherein the covering portion is a metal case that houses the sensor body.   The temperature sensor according to claim 2, wherein the covering portion is a conductive film that covers the sensor body.   The said conductive member is a conductive adhesive, The said contact part and the part which has the electroconductivity in the said battery unit are adhere | attached by this conductive adhesive. Temperature sensor.   The temperature sensor as described in any one of Claims 1-5 currently hold | maintained or urged | biased with respect to the said battery unit.   The temperature sensor according to claim 1, wherein the conductive part of the battery unit is a conductive part of the battery cell.   The part which has electroconductivity in the said battery unit is a temperature sensor as described in any one of Claims 1-6 which is a part which has electroconductivity in the attachment member thermally connected with the said battery cell. A mounting step of attaching a temperature sensor having a conductive contact portion and a measurement portion electrically connected to each other on the outer surface to the battery unit so that the contact portion contacts a conductive portion of the battery unit; ,
A measurement step of measuring an electrical resistance between the measurement part of the temperature sensor and a conductive part electrically connected to a part of the battery unit to which the temperature sensor is attached;
And a determination step of determining a contact state between the temperature sensor and the battery unit based on the electrical resistance measured in the measurement step.

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