JP2013101058A - Secondary battery state detection system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To exactly detect a state of a secondary battery.SOLUTION: A secondary battery state detection system for detecting a state of a secondary battery 10 loaded on a vehicle has: electric conduction means (an electric conduction part 21) for conducting charge current or discharge current to the secondary battery; and measurement means (a detection part 22) for measuring voltage when current is conducted to the secondary battery by the electric conduction means, in which a first interconnect line (wiring 25 for discharge) which connects the electric conduction means with the secondary battery is connected with a second interconnect line (wiring 26 for detection) which connects the measurement means with the secondary battery so that common impedance as impedance which the first interconnect line and the second interconnect line commonly have is minimized.

Description

  The present invention relates to a secondary battery state detection system.

  In order to determine the deterioration state of the secondary battery, the secondary battery is discharged, the internal impedance of the secondary battery is determined based on the voltage and current at the time of discharge, and the secondary battery is determined based on the determined internal impedance. For example, Patent Literature 1 discloses a technique for determining a deterioration state.

JP 2006-284537 A

  By the way, when the deterioration state of the secondary battery mounted on the vehicle is determined by the above-described technique, for example, the connection between the secondary battery and the device is considered in consideration of the ease of wiring operation when the vehicle is assembled. The method is often determined. In that case, depending on the routing of the wiring, a voltage drop occurs due to the electrical resistance of the wiring, so that the detected response voltage is not accurate. As a result, there is a problem that the state of the secondary battery cannot be accurately detected because the measured internal impedance causes an error.

  Then, this invention aims at providing the secondary battery state detection system which can detect the state of a secondary battery correctly.

In order to solve the above-described problems, the present invention provides a secondary battery state detection system for detecting a state of a secondary battery mounted on a vehicle, energizing means for passing a charging current or a discharging current through the secondary battery, Measuring means for measuring a voltage when current is passed to the secondary battery by the energizing means, a first connection line connecting the energizing means and the secondary battery, the measuring means and the second battery The first connection line and the second connection line are connected so that a common impedance as an impedance shared by a second connection line connecting a secondary battery is minimized.
According to such a configuration, it is possible to accurately detect the state of the secondary battery.

According to another invention, in addition to the above invention, the first connection line and the second connection line are branch portions in a bus bar, a harness, or a fuse, and are closest to the terminal of the secondary battery. It is connected to the part.
According to such a configuration, the state of the secondary battery can be detected more accurately by minimizing the common impedance.

Further, in addition to the above invention, in another invention, the first connection line and the second connection line are respectively connected to different electrical connection boxes, and the electrical connection box to which the second connection line is connected and the The resistance value of the conductor connecting the terminal of the secondary battery is smaller than the resistance value of the conductor connecting the terminal of the secondary battery and the electrical connection box to which the first connection line is connected, To do.
According to such a structure, the influence of the voltage drop by the electric current which leads to the load connected to the electrical junction box can be reduced, and the state of the secondary battery can be detected accurately.

According to another invention, in addition to the above invention, the first connection line and the second connection line are respectively connected to different electrical connection boxes and connected to the electrical connection box to which the second connection line is connected. The average power consumption of the loaded load is smaller than the average power consumption of the load connected to the electrical connection box to which the first connection line is connected.
According to such a structure, the influence of the voltage drop by the current leading to the load connected to the electrical junction box can be reduced, and the state of the secondary battery can be detected more accurately.

According to another invention, in addition to the above invention, the first connection line and the second connection line are respectively connected to different electrical connection boxes and connected to the electrical connection box to which the second connection line is connected. The usage frequency of the load to be applied is smaller than the usage frequency of the load connected to the electrical connection box to which the first connection line is connected.
According to such a structure, the influence of the voltage drop by the current leading to the load connected to the electrical junction box can be reduced, and the state of the secondary battery can be detected more accurately.

In addition to the above invention, another invention is characterized in that the first connection line and the second connection line are directly connected to a terminal of the secondary battery.
According to such a configuration, the state of the secondary battery can be detected more accurately by minimizing the influence of the voltage drop.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the secondary battery state detection system which can detect the state of a secondary battery correctly.

It is a figure which shows the structural example of the secondary battery state detection system which concerns on 1st Embodiment of this invention. It is a figure which shows the structural example of the state detection apparatus shown in FIG. It is a figure which shows the connection relation of the state detection apparatus, secondary battery, and electrical junction box which are shown in FIG. It is a figure which shows the connection relation of the conventional state detection apparatus, a secondary battery, and an electrical junction box. It is a figure which shows the change by the temperature of the internal impedance of a secondary battery, and conductor resistance. It is a figure which shows the structural example of the secondary battery state detection system which concerns on 2nd Embodiment of this invention. It is a figure which shows the common impedance at the time of performing wiring different from FIG. It is a figure which shows the structural example of the secondary battery state detection system which concerns on 3rd Embodiment of this invention. It is a figure which shows the structural example of the secondary battery state detection system which concerns on 4th Embodiment of this invention. It is a figure which shows the structural example of the secondary battery state detection system which concerns on 5th Embodiment of this invention. It is a figure which shows the structural example of the secondary battery state detection system which concerns on 6th Embodiment of this invention. It is a figure which shows the deformation | transformation embodiment of this invention.

  Next, an embodiment of the present invention will be described.

(A) Description of First Embodiment FIG. 1 is a diagram illustrating a configuration example of a secondary battery state detection system according to an embodiment of the present invention. As shown in this figure, the secondary battery state detection system according to the present embodiment includes a secondary battery 10, a state detection device 20, and electrical connection boxes 30 to 50.

  Here, the secondary battery 10 is constituted by a lead storage battery using, for example, lead dioxide for the positive electrode (anode plate), spongy lead for the negative electrode (cathode plate), and dilute sulfuric acid as the electrolyte. A negative electrode terminal 11 and a positive electrode terminal 12 are provided on the upper surface of the housing.

  The state detection device 20 is fixed to the negative electrode terminal 11 by, for example, a fastening member (not shown). Further, the negative electrode terminal 11 is grounded to the vehicle body by an earth cable 13. An electrical connection box 30 is connected to the positive terminal 12. The electrical junction box is configured by incorporating a bus bar, a fuse, and the like in a box-shaped housing, and has a function of distributing power to a plurality of loads. "," Relay box "or" fuse box ".

  Electrical connection boxes 40 and 50 are connected to the electrical connection box 30 by wirings 14 and 15. A plurality of loads (not shown) are connected to the electrical connection boxes 40 and 50, respectively. The wiring 16 connected to the electrical junction box 30 is connected to a starter motor (not shown) that is an electric motor for starting the engine.

  FIG. 2 is a diagram illustrating a detailed configuration example of the state detection device 20 illustrated in FIG. 1. As shown in FIG. 2, the state detection device 20 includes a power supply unit 21, a detection unit 22, a calculation unit 23, and a control unit 24 as main components, and detects the state of the secondary battery 10.

  Here, the energization unit 21 is connected to the positive electrode terminal 12 of the secondary battery 10 via the discharge wiring 25, and causes the secondary battery 10 to discharge a pulsed current under the control of the control unit 24. Note that the energization unit 21 may charge the secondary battery 10 instead of discharging it. The detection unit 22 detects a current flowing through the secondary battery 10 via the discharge wiring 25 and the energization unit 21 when the pulsed current is energized by the energization unit 21, and also via the detection wiring 26. Then, the voltage of the secondary battery 10 is detected, and the detection result is supplied to the calculation unit 23.

  The calculation unit 23 calculates, for example, the internal impedance of the secondary battery 10 based on the voltage and current detected by the detection unit 22, and the charge rate and deterioration of the secondary battery 10 based on the calculated internal impedance. The degree is obtained and supplied to the control unit 24. The control unit 24 controls the energization unit 21 to energize the secondary battery 10 with a pulsed current, and the information such as the internal impedance, the charging rate, and the degree of deterioration calculated by the calculation unit 23 is not shown. It supplies to an apparatus (for example, ECU (Engine Control Unit)).

  FIG. 3 is a diagram illustrating a connection state of the discharge wiring 25 and the detection wiring 26 in the first embodiment. As shown in this figure, the electrical junction box 30 has a bus bar 31 formed by punching a conductive flat plate made of copper or a copper-based alloy or the like with a press, and a plurality of fuses 32 are connected to the bus bar 31. Each fuse 32 is connected to a load. In the example of FIG. 3, the fuse 32 is used, but a relay or the like may be used instead of the fuse 32. The electrical connection boxes 40 and 50 have the same configuration.

  In the first embodiment, the discharge wiring 25 and the detection wiring 26 are respectively connected to the fuse 32 on the side closest to the positive electrode terminal 12 of the secondary battery 10 in the electrical connection box 30.

  Next, the operation of the first embodiment will be described. In the first embodiment, when the state detection device 20 detects the state of the secondary battery 10, the control unit 24 controls the energization unit 21 to pass, for example, a pulsed current through the secondary battery 10. The detection unit 22 detects the response voltage of the secondary battery 10 when the pulsed current is passed through the detection wiring 26.

  By the way, in the prior art, the connection method has been determined mainly in consideration of the ease of wiring routing during vehicle assembly. For example, the connection shown in FIG. It was. In the example of FIG. 4, the discharge wiring 25 and the detection wiring 26 are connected to the electrical junction box 40. In such a case, the discharge wiring 25 and the detection wiring 26 are connected to the positive electrode terminal 12 of the secondary battery 10 via the wirings 33 and 34. Since the wirings 33 and 34 have an electrical impedance, when pulse discharge is performed, a voltage drop is generated by an amount corresponding to these impedances. For this reason, since the voltage detected by the detection unit 22 drops by an amount corresponding to the impedance of the wirings 33 and 34, it is obtained by calculating the internal impedance of the secondary battery 10 using the detected voltage. The value will have an error corresponding to the voltage drop. That is, since the discharge wiring 25 and the detection wiring 26 have the impedance of the wirings 33 and 34 as a common impedance, an error increases when the common impedance is large.

  Further, as indicated by black circles in FIG. 5, the impedance of the conductor including the bus bar, the harness, and the fuse increases according to the temperature. For this reason, in a place where the temperature is high, such as an engine room, the impedance increases with an increase in temperature, and the error becomes larger. As for the internal impedance of the secondary battery 10, as shown in FIG. 5, the behavior due to the temperature characteristics is somewhat clear, and since the secondary battery 10 is considered to have a constant temperature as a whole, there is no problem. It is also possible to perform correction by temperature. However, with regard to the impedance of the conductor, when the length of the conductor is long, the temperature varies depending on the location where the conductor is disposed (for example, the temperature around the engine is high and the temperature around the front grill where the outside air flows is high). It is difficult to make corrections based on temperature. Further, when a fuse is included in the conductor, since the fuse is a metal compound, it is difficult to correct by a single temperature coefficient, and thus correction by temperature becomes more difficult.

  On the other hand, in the first embodiment, as shown in FIG. 3, the common impedance of the discharge wiring 25 and the detection wiring 26 is only the impedance of the wiring 33. As shown in FIG. 1, the electrical junction box 30 is disposed in the immediate vicinity of the positive electrode terminal 12, and a member having a low electrical resistance is used in the shortest distance so that a large current can be passed. For this reason, since the impedance (resistance component and inductance component) of the wiring 33 is very small, the voltage drop due to the wiring 33 is very small, so that the occurrence of errors due to the voltage drop can be reduced. Moreover, since the distance of the wiring 33 is short, there is little temperature difference by the place where wiring is arrange | positioned. Furthermore, the wiring 33 is disposed in the immediate vicinity of the secondary battery 10. For this reason, it is also possible to detect the temperature of the secondary battery 10 and perform temperature correction for the common impedance based on the detected temperature.

  As described above, in the first embodiment, the discharge wiring 25 and the detection wiring 26 are connected to the fuse 32 closest to the positive terminal 12 among the fuses 32 built in the electrical connection box 30 closest to the positive terminal 12. Was connected. For this reason, it is possible to reduce the occurrence of errors due to the voltage drop due to the common impedance.

  In the example of FIG. 3, the detection wiring 26 is connected to the fuse 32 closest to the positive terminal 12 and the discharge wiring 25 is connected to the second closest fuse 32, but these relationships are reversed. There may be. That is, the discharge wiring 25 may be connected to the fuse 32 closest to the positive terminal 12 and the detection wiring 26 may be connected to the fuse 32 closest to the second terminal.

(B) Description of Second Embodiment FIG. 6 is a diagram showing a configuration example of the second embodiment of the present invention. In FIG. 6, parts corresponding to those in FIG. 3 are denoted by the same reference numerals, and description thereof is omitted. In FIG. 6, compared to the case of FIG. 3, the electrical connection box 40 is connected to the fuse 32 closest to the input side of the electrical connection box 30, and the electrical connection box 50 is connected to the fuse 32 closest to the second. In addition, electrical connection boxes 60 and 70 are connected to the third and fourth fuses 32, respectively. Further, the discharge wiring 25 is connected to the fuse 42 closest to the input side of the electrical connection box 40, and the detection wiring 26 is connected to the fuse 52 closest to the input side of the electrical connection box 50. Other configurations are the same as those in FIG.

  In the case of the second embodiment, what corresponds to the common impedance of the discharge wiring 25 and the detection wiring 26 is the impedance of the wiring 33 surrounded by a broken line in the figure. On the other hand, as shown in FIG. 7, when the discharge wiring 25 is connected to the electrical junction box 60 and the detection wiring 26 is connected to the electrical junction box 70, the portion surrounded by the broken line of the bus bar 31 of the electrical junction box 30 Since it becomes common impedance, the voltage drop by this part arises and is not preferable. In the second embodiment shown in FIG. 6, the voltage drop due to the energization of the energization unit 21 only needs to take into account the voltage drop due to the impedance of the wiring 33, and therefore, due to the common impedance, as in the first embodiment. The generation of errors can be reduced.

(C) Description of Third Embodiment FIG. 8 is a diagram illustrating a configuration example of a third embodiment of the present invention. In FIG. 8, parts corresponding to those in the second embodiment shown in FIG. In FIG. 8, compared with FIG. 6, the resistance of the portion surrounded by the broken line connecting the electric connection box 30 and the electric connection box 40 is R1, and the broken line connecting the electric connection box 30 and the electric connection box 50 is When the resistance of the enclosed portion is R2, R1> R2. Moreover, in FIG. 8, illustration of the part relevant to the electrical junction boxes 60 and 70 is omitted. The rest of the configuration is the same as in FIG. In FIG. 8, it is assumed that the currents flowing through the loads connected to the electrical junction box 40 and the electrical junction box 50 are substantially the same.

  In the third embodiment, the wiring is set in consideration of the voltage drop due to the current leading to the load connected to the electrical junction box 50. That is, when an electric current is passed to the load connected to the electric connection box 50, the electric current is a portion of the conductor (wiring, harness, and) surrounded by a broken line connecting the electric connection box 30 and the electric connection box 40. Bus bar, etc.) and wiring 33. For this reason, a voltage drop occurs due to the impedance of the conductor in the portion surrounded by the wiring 33 and the broken line. Although it is difficult to reduce the voltage drop due to the wiring 33 by the wiring method, the voltage drop due to the conductor in the portion surrounded by the broken line can be reduced. That is, the resistance of the portion surrounded by the broken line connecting the electric connection box 30 and the electric connection box 40 is R1, and the resistance of the portion surrounded by the broken line connecting the electric connection box 30 and the electric connection box 50 is R2. In this case, by setting the connection method so that R1> R2, the voltage drop in the case where the current is passed to the load can be reduced as much as possible, and the error included in the detected internal impedance can be reduced. That is, according to the third embodiment, by reducing the common impedance, the influence of the voltage drop due to energization is reduced, and the influence of the voltage drop due to the current connected to the load connected to the electrical junction box is also reduced. Can do.

(D) Explanation of 4th Embodiment FIG. 9: is a figure which shows the structural example of 4th Embodiment of this invention. In FIG. 9, parts corresponding to those of the third embodiment shown in FIG. In FIG. 9, when the average power consumption of the load connected to the electrical connection box 40 is W1 and the average power consumption of the load connected to the electrical connection box 50 is W2, W1> W2. Is set. The other configuration is the same as in the case of FIG. In the following description, the resistances R1 and R2 surrounded by a broken line in FIG. 8 will be described as R1≈R2.

  In the fourth embodiment, the wiring is set in consideration of the voltage drop due to the current flowing through the load connected to the electrical junction box 50 as in the third embodiment. That is, when a current is passed to the load connected to the electrical junction box 50, as described above, a voltage drop occurs due to the impedance of the conductor surrounded by the wiring 33 and the broken line shown in FIG. Therefore, in the fourth embodiment, the detection wiring 26 is connected to the electrical junction box with the smallest average power consumption flowing to the load. That is, in the example of FIG. 9, when there are two electrical connection boxes 40 and 50, and the power consumptions are W1 and W2, respectively, and W1> W2, the electrical connection box with the smaller average power consumption 50 is connected to the detection wiring 26. In this way, by connecting the detection wiring 26 to the electrical connection box 50 having a low average power consumption, the voltage drop caused by the conductor between the electrical connection boxes can be reduced, so that the detected internal impedance can be reduced. The included error can be minimized. Here, the average power consumption indicates the average power consumption of all loads connected to the electrical connection boxes 40 and 50. In addition, as average power consumption, it is also possible to use the average of power consumption in the period when the energization part 21 of the state detection apparatus 20 is highly likely to operate as average power consumption.

(E) Description of Fifth Embodiment FIG. 10 is a diagram illustrating a configuration example of a fifth embodiment of the present invention. 10, parts corresponding to those in the third embodiment shown in FIG. 8 are denoted by the same reference numerals, and description thereof is omitted. In FIG. 10, when the usage frequency of the load connected to the electrical connection box 40 is F1, and the usage frequency of the load connected to the electrical connection box 50 is F2, F1> F2 is set. ing. The other configuration is the same as in the case of FIG. In the following description, the resistances R1 and R2 surrounded by a broken line in FIG. 8 will be described as R1≈R2.

  In the fifth embodiment, the wiring is set in consideration of the voltage drop due to the current flowing through the load connected to the electrical junction box 50 as in the third embodiment. That is, when a current is passed to the load connected to the electrical junction box 50, as described above, a voltage drop occurs due to the impedance of the conductor surrounded by the wiring 33 and the broken line shown in FIG. Therefore, in the fifth embodiment, the detection wiring 26 is connected to the electrical junction box that uses the least load. That is, in the example of FIG. 10, there are two electrical connection boxes 40 and 50, and the frequency of use is F 1 and F 2. When F 1> F 2, the electrical connection box 50 with the lower use frequency is used. The detection wiring 26 is connected to the. In this way, by connecting the detection wiring 26 to the electrical connection box 50 that is less frequently used, the voltage drop caused by the conductor between the electrical connection boxes can be reduced, and thus included in the detected internal impedance. Error can be reduced. Here, the usage frequency indicates the usage frequency of all loads connected to the electrical junction boxes 40 and 50. In addition, it is also possible to use the usage frequency in a period when the possibility that the energization unit 21 of the state detection device 20 operates is high.

(F) Description of Sixth Embodiment FIG. 11 is a diagram illustrating a configuration example of a sixth embodiment of the present invention. In FIG. 11, parts corresponding to those of the first embodiment shown in FIG. In FIG. 11, the detection wiring 26 is connected to the electrical connection box 30, and the discharge wiring 25 is connected to the electrical connection box 40. Further, the electrical connection box 40 is directly connected to the positive terminal 12 of the secondary battery 10 by the wiring 43. Other configurations are the same as those in FIG.

  In the sixth embodiment, the common impedance of the discharge wiring 25 and the detection wiring 26 is only the impedance of the positive electrode terminal 12. For this reason, since the voltage drop when energized by the energization unit 21 can be made extremely small, the internal impedance can be accurately measured. Note that the wiring 43 may be connected to any location of the wiring 33 instead of being directly connected to the positive terminal 12.

(G) Description of Modified Embodiment It goes without saying that the above embodiment is merely an example, and the present invention is not limited to the case described above. For example, in the above embodiment, the state detection device 20 provided on the negative electrode terminal 11 side has been described as an example, but the present invention can also be applied to a state detection device provided on the positive electrode terminal 12 side. FIG. 12 is a diagram showing a configuration example when the state detection device 20A provided on the positive electrode terminal 12 side is applied to the second embodiment shown in FIG. In the example of this figure, the state detection device 20 </ b> A is disposed on the positive electrode terminal 12 side of the secondary battery 10. Further, the discharge wiring 25 is connected to the electrical junction box 40, and the detection wiring 26 is connected to the electrical junction box 50. Even in such a configuration, the detection error of the internal impedance can be reduced by reducing the common impedance of the discharge wiring 25 and the detection wiring 26. The example of FIG. 12 is an example in which the state detection device 20A is applied to the second embodiment shown in FIG. 6, but the state detection device 20A is applied to the other first, third to sixth embodiments. It goes without saying that it is possible.

  In addition, each of the embodiments described above is not only implemented alone, but can also be implemented in combination of a plurality, for example. As described above, by implementing in combination, the internal impedance can be obtained more accurately by reducing the influence of the common impedance and the influence of the load.

  Further, in each of the above embodiments, the bus bar in the electrical junction box is used as a branch portion, and after branching, the discharge wiring 25 and the detection wiring 26 are connected via a fuse. It is not limited to a bus bar. For example, a branch may be made by a harness, or a branch may be made by a fuse.

  Further, in each of the embodiments described above, the case where the energization unit 21 is discharged has been described as an example. However, even when charging is performed instead of discharging, a voltage drop due to energization occurs as in the case of discharging. Therefore, the present invention can be applied even when charging.

  Further, in each of the above embodiments, all the electrical connection boxes are configured by the bus bars and the fuses, but the electrical connection boxes configured by the bus bars and the relays may be included at least in part.

  Further, in each of the above embodiments, the detection wiring 26 is used only for the purpose of detecting the voltage of the secondary battery 10, but the power supply power of the state detection devices 20, 20A is obtained through the detection wiring 26. You may do it.

DESCRIPTION OF SYMBOLS 10 Secondary battery 11 Negative electrode 12 Positive electrode 13 Ground cable 14-16 Wiring 20,20A State detection apparatus 21 Current supply part (energization means)
22 Detection unit (measuring means)
23 Calculation unit 24 Control unit 25 Discharge wiring (first connection line)
26 Wiring for detection (second connection line)
27 Wiring for ground 30 to 70 Electric junction box 31, 41, 51, 61, 71 Bus bar 32, 42, 52, 62, 72 Fuse 33, 43 Wiring

Claims (6)

In a secondary battery state detection system for detecting a state of a secondary battery mounted on a vehicle,
Energizing means for passing charging current or discharging current through the secondary battery;
Measuring means for measuring a voltage when current is passed to the secondary battery by the energizing means,
The first connection line for connecting the energization means and the secondary battery, and the second connection line for connecting the measurement means and the secondary battery have a common impedance as a common impedance. A secondary battery state detection system, wherein one connection line and the second connection line are connected.   The first connection line and the second connection line are branch portions in a bus bar, a harness, or a fuse, and are connected to a branch portion closest to a terminal of the secondary battery. 2. The secondary battery state detection system according to 1.   The first connection line and the second connection line are respectively connected to different electrical connection boxes, and a resistance value of a conductor connecting the electrical connection box to which the second connection line is connected and a terminal of the secondary battery. The secondary battery state according to claim 1 or 2, wherein a resistance value of a conductor connecting the electrical connection box to which the first connection line is connected and a terminal of the secondary battery is smaller. Detection system.   The first connection line and the second connection line are respectively connected to different electrical connection boxes, and an average power consumption of a load connected to the electrical connection box to which the second connection line is connected is the first connection line. The secondary battery state detection system according to any one of claims 1 to 3, wherein the secondary battery state detection system is smaller than an average power consumption of a load connected to the electric junction box to which a line is connected.   The first connection line and the second connection line are respectively connected to different electrical connection boxes, and the usage frequency of the load connected to the electrical connection box to which the second connection line is connected is the first connection line. 4. The secondary battery state detection system according to claim 1, wherein the secondary battery state detection system is smaller than a frequency of use of a load connected to the electrical junction box to which is connected.   The secondary battery state detection system according to claim 1, wherein the first connection line and the second connection line are directly connected to a terminal of the secondary battery.

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