Temperature detection device and voltage detection device

Abstract

To provide a temperature detection device and a voltage detection device capable of appropriately detecting the temperature of a detection line.SOLUTION: A temperature detection device detects the temperatures of a plurality of voltage detection lines connected to a plurality of battery cells in a battery as detection line temperatures, and includes a temperature acquisition unit that acquires the temperature of the battery as the detection line temperature.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a temperature detection device and a voltage detection device. [Background technology]

[0002] Patent Document 1 listed below discloses a battery system capable of accurately estimating the state of charge of a battery cell. This battery system includes a battery cell and a state of charge estimation device, and the state of charge estimation device calculates the state of charge of the battery cell during a charge / discharge period based on the terminal voltage of the battery cell during non-charge / discharge periods before and after the charge / discharge period, calculates the internal impedance of the battery cell during the charge / discharge period based on the current flowing through the battery cell during the charge / discharge period, the terminal voltage of the battery cell during the charge / discharge period, and the calculated state of charge during the charge / discharge period, and updates internal impedance information stored in a storage unit based on the temperature of the battery cell during the charge / discharge period and the calculated internal impedance. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-231988 Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, in order to accurately detect the inter-electrode voltage (cell voltage) of a battery cell based on the terminal voltage (electrode voltage) of the battery cell, it is necessary to accurately detect the temperature (detection line temperature) of multiple voltage detection lines (harnesses) provided between multiple battery cells in the battery and a voltage detection device that detects the cell voltage of each battery cell.

[0005] However, for harnesses with reduced diameters and FPCs, the wire temperature cannot be properly detected when using a temperature sensor such as a thermocouple due to the harness's small thermal capacity, which results in the problem of being unable to properly correct the electrode voltage of the battery cell for temperature.

[0006] The present invention has been made in view of the above circumstances, and has an object to provide a temperature detection device and a voltage detection device that are capable of appropriately detecting the temperature of a detection line. [Means for solving the problem]

[0007] In order to achieve the above object, the present invention adopts, as a first solution related to a temperature detection device, a temperature detection device that detects the temperatures of multiple voltage detection lines connected to multiple battery cells in a battery as detection line temperatures, and that is equipped with a temperature acquisition unit that acquires the temperature of the battery as the detection line temperature.

[0008] The present invention adopts, as a second solution related to the temperature detection device, a solution in which, in the above-mentioned first solution, the temperature acquisition unit includes an impedance acquisition unit that acquires the internal impedance of the battery based on an AC impedance method, and a temperature conversion unit that converts the internal impedance into the detection line temperature.

[0009] In the present invention, as a third solution related to a temperature detection device, the second solution described above is adopted, in which the battery is a series connection of multiple battery modules, and the temperature acquisition unit acquires the detection line temperature for each battery module.

[0010] The present invention provides a fourth solution related to the temperature detection device, which is the third solution described above, in which the impedance acquisition unit includes a selection switch that sequentially applies an AC waveform to the plurality of battery modules in a predetermined order, and acquires the internal impedance for each battery module based on a response signal obtained from the battery module by applying the AC waveform.

[0011] In the present invention, as a solution related to a voltage detection device, a solution is adopted in which the voltage detection device is provided with a temperature detection device related to any one of the first to fourth solutions above, and a voltage correction unit that corrects the cell voltages of the plurality of battery cells based on the detection line temperature detected by the temperature detection device. [Effects of the Invention]

[0012] According to the present invention, it is possible to provide a temperature detection device and a voltage detection device that can appropriately detect the temperature of a detection line. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a block diagram showing a configuration of a voltage detection device according to an embodiment of the present invention; [Figure 2] 4 is a flow chart showing the operation of the voltage detection device according to one embodiment of the present invention. [Figure 3] 4 is a characteristic diagram showing the operation of the voltage detection device according to the embodiment of the present invention. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The battery control device A according to this embodiment is an ECU (Electronic Control Unit) that controls the battery B based on its voltage, as shown in FIG.

[0015] This battery control device A detects the voltage of battery B and also detects the temperatures (detection line temperatures) of multiple voltage detection lines L0 to L4. That is, the battery control device A obtains the detection line temperatures of multiple voltage detection lines L0 to L4, and thereby performs appropriate temperature correction on the detected voltage of battery B. Such a battery control device A corresponds to the temperature detection device and voltage detection device according to the present invention.

[0016] As shown in the figure, battery B is formed by connecting multiple (four) battery modules M1 to M4 in series. Each of the multiple battery modules M1 to M4 has multiple battery cells (not shown) connected in series. That is, the output voltage (module voltage) of the multiple battery modules M1 to M4 is the sum of the inter-electrode voltages (cell voltages) of the multiple battery cells.

[0017] Furthermore, the output voltage (battery voltage) of battery B is the sum of the module voltages of the multiple battery modules M1 to M4. That is, the battery voltage of battery B is the sum of the cell voltages of all the battery cells that make up the multiple battery modules M1 to M4.

[0018] 1 shows four battery modules M1 to M4, the number of battery modules is not limited to four. That is, the battery of the present invention may be composed of one battery module, or may be composed of two, three, five or more battery modules connected in series.

[0019] Although not shown in Fig. 1, battery B is additionally provided with a current sensor that detects the output current as a battery current. Since the four battery modules M1-M4 are connected in series, the battery current is also the output current (module current) of the four battery modules M1-M4. Such a current sensor outputs a module current detection signal to battery control device A.

[0020] The multiple (five) voltage detection lines L0 to L4 are electric wires that connect the electrodes of each battery cell in the battery B to the battery control device A. The five voltage detection lines L0 to L4 shown in Fig. 1 are a portion (representative) of all voltage detection lines. Of the multiple voltage detection lines L0 to L4, the zeroth voltage detection line L0 has one end connected to the negative output terminal of the first battery module M1.

[0021] One end of the first voltage detection line L1 is connected to the positive output terminal of the first battery module M1 and the negative output terminal of the second battery module M2, and one end of the second voltage detection line L2 is connected to the positive output terminal of the second battery module M2 and the negative output terminal of the third battery module M3.

[0022] One end of the third voltage detection line L3 is connected to the positive output terminal of the third battery module M3 and the negative output terminal of the fourth battery module M4, and one end of the fourth voltage detection line L4 is connected to the positive output terminal of the fourth battery module M4.

[0023] In reality, voltage detection lines are provided not only at the five contact points a to e on the battery B as shown in the figure, but also between the positive and negative electrodes of all the battery cells and the input terminals of the battery control device A, respectively.

[0024] As shown in the figure, the battery control device A includes a selection switch 1, an AC waveform generating circuit 2, and an MPU 3. The battery control device A detects the cell voltage of each battery cell based on the electrode voltages of the multiple battery cells input via multiple voltage detection lines, represented by five voltage detection lines L0 to L4.

[0025] As shown in the figure, the selection switch 1 is provided between a plurality of voltage detection lines L0 to L4 and the AC waveform generating circuit 2. This selection switch 1 has five selection contacts s0 to s4 and two common contacts k1 and k2, and the connection relationship between the five selection contacts s0 to s4 and the two common contacts k1 and k2 is set by a switching signal input from the MPU 3.

[0026] That is, the two common contacts k1, k2 are selectively connected to one of the five selection contacts s0 to s4 based on a switching signal. Of the two common contacts k1, k2, the first common contact k1 is selectively connected to one of the five selection contacts s0 to s4 based on a switching signal. Also, the second common contact k2 is selectively connected to one of the five selection contacts s0 to s4 based on a switching signal.

[0027] Of the five selection contacts s0 to s4, the 0th selection contact s0 is connected to the other end of the 0th voltage detection line L0. Furthermore, the first selection contact s1 is connected to the other end of the first voltage detection line L1. The second selection contact s2 is connected to the other end of the second voltage detection line L2. The third selection contact s3 is connected to the other end of the third voltage detection line L3. Furthermore, the fourth selection contact s4 is connected to the other end of the fourth voltage detection line L4.

[0028] On the other hand, of the two common contacts k1 and k2, the first common contact k1 is connected to one of a pair of output terminals in the AC waveform generating circuit 2. The second common contact k2 is connected to the other of the pair of output terminals in the AC waveform generating circuit 2.

[0029] The AC waveform generating circuit 2 is a signal generator that generates an AC signal of a predetermined frequency based on a control signal input from the MPU 3. This AC signal is, for example, a sine wave signal. The AC waveform generating circuit 2 outputs an AC signal to the selection switch 1 to obtain the internal impedance of each battery module M1 to M4 based on the AC impedance method.

[0030] The MPU 3 executes a control program stored in advance to control the selection switch 1 and the AC waveform generating circuit 2. That is, the MPU 3 generates a switching signal based on the control program and outputs it to the selection switch 1. The MPU 3 also generates a control signal based on the control program and outputs it to the AC waveform generating circuit 2.

[0031] 1, the battery control device A includes a voltage detection circuit in addition to the above-mentioned selection switch 1, AC waveform generating circuit 2, and MPU 3. This voltage detection circuit detects the inter-electrode voltage of each battery (the differential voltage between the positive electrode voltage and the negative electrode voltage) as a cell voltage based on the electrode voltages of multiple battery cells (not shown) input from battery B via multiple voltage detection lines L0 to L4, etc. Such a voltage detection circuit outputs voltage detection signals indicating the cell voltages of the multiple battery cells to MPU 3.

[0032] Furthermore, in this battery control device A, electrode voltages input from multiple voltage detection lines L0 to L4 are output as module voltage detection signals to the MPU 3. These module voltage detection signals, together with module current detection signals input from the above-mentioned current sensors to the MPU 3, are used to estimate the internal impedance of each of the battery modules M1 to M4 based on the AC impedance method.

[0033] In this embodiment, the MPU 3 estimates the internal impedance of each battery module M1-M4 (battery B) based on the AC impedance method by receiving the module voltage detection signal and the module current detection signal. The module voltage detection signal and the module current detection signal in this embodiment are response signals obtained from each battery module M1-M4 in response to the application of an AC waveform.

[0034] That is, in this embodiment, the MPU 3 acquires the internal impedance for each of the battery modules M1 to M4 (battery B) based on the response signal obtained by applying AC waveforms to the multiple battery modules M1 to M4 sequentially in a predetermined order using the selection switch 1 and the AC waveform generating circuit 2.

[0035] The selection switch 1, AC waveform generating circuit 2, and MPU 3 constitute a temperature acquisition unit of the present invention. The selection switch 1, AC waveform generating circuit 2, and MPU 3 also function as an impedance acquisition unit that acquires the internal impedance of each battery module M1 to M4 (battery B) based on the AC impedance method.

[0036] Furthermore, the MPU 3 functions as a temperature conversion unit that converts the internal impedances of the battery modules M1 to M4 (battery B) acquired by the impedance acquisition unit into detection line temperatures of the voltage detection lines L0 to L4. That is, the temperature acquisition unit of the present invention includes an impedance acquisition unit and a temperature conversion unit.

[0037] Next, the characteristic operation of the battery control device A according to this embodiment will be described in detail with reference to the flowchart of FIG.

[0038] A characteristic operation of this battery control device A is a temperature detection operation that acquires the temperatures of the multiple voltage detection lines L0 to L4 as detection line temperatures by using the internal impedance of battery B estimated based on the AC impedance method. Another characteristic operation is a temperature correction operation that corrects the cell voltage of each battery cell in battery B based on the detection line temperatures acquired by the temperature detection operation.

[0039] As a characteristic operation of this type, the battery control device A first generates an AC waveform (step S1). That is, the MPU 3 in the battery control device A outputs a control signal instructing the start of generation of an AC waveform to the AC waveform generating circuit 2, thereby causing the AC waveform generating circuit 2 to output an AC waveform to the selection switch 1.

[0040] In addition to outputting the control signal, the MPU 3 also outputs a switching signal to the selection switch 1 to instruct selection in the order of, for example, the first battery module M1 → the second battery module M2 → the third battery module M3 → the fourth battery module M4. As a result, the AC waveform is applied sequentially via the multiple voltage detection lines L0 to L4 in the order of the first battery module M1 → the second battery module M2 → the third battery module M3 → the fourth battery module M4.

[0041] Then, the MPU 3 estimates the internal impedances of the first to fourth battery modules M1 to M4 by taking in the module current detection signals and module voltage detection signals when the AC waveform is applied (step S2).

[0042] That is, the MPU 3 estimates the internal impedance of the first to fourth battery modules M1 to M4 by performing signal processing based on the AC impedance method on the module current detection signal and the module voltage detection signal when the AC waveform is applied. Note that since the process of acquiring the internal impedance (AC impedance) of a battery based on the AC impedance method is well known, details will be omitted.

[0043] Here, the internal impedance of the first to fourth battery modules M1 to M4 has temperature dependency as shown in Fig. 3. That is, the internal impedance becomes an AC impedance that differs depending on the operating temperature of the first to fourth battery modules M1 to M4. The MPU 3 stores in advance a data table (conversion table) that indicates the relationship between the internal impedance and the operating temperature.

[0044] Using this conversion table, the MPU3 converts the internal impedances of the first to fourth battery modules M1 to M4 into operating temperatures of the first to fourth battery modules M1 to M4 (step S3). Because multiple voltage detection lines L0 to L4 are connected to the first to fourth battery modules M1 to M4, the operating temperatures of the first to fourth battery modules M1 to M4 can be considered as the temperatures of the multiple voltage detection lines L0 to L4, i.e., detection line temperatures.

[0045] That is, the operating temperature of the first battery module M1 can be regarded as the detection line temperature of the 0th voltage detection line L0 and the first voltage detection line L1, and the operating temperature of the second battery module M2 can be regarded as the detection line temperature of the first voltage detection line L1 and the second voltage detection line L2.

[0046] The operating temperature of the third battery module M3 can be considered to be the detection line temperatures of the second voltage detection line L2 and the third voltage detection line L3, and the operating temperature of the fourth battery module M4 can be considered to be the detection line temperatures of the third voltage detection line L3 and the fourth voltage detection line L4.

[0047] The MPU 3 performs the process of acquiring the internal impedances of the first to fourth battery modules M1 to M4 in chronological order at predetermined time intervals in step S3, and then determines whether a significant impedance change has occurred by comparing the internal impedance acquired this time with the internal impedance acquired one interval before (step S4).

[0048] If the determination in step S4 is "Yes," the MPU 3 performs temperature correction on the cell voltages of the battery cells separately acquired from the voltage detection circuit (step S5). The MPU 3 stores in advance a data table (correction table) showing the relationship between the amount of impedance change and the amount of voltage correction, for example.

[0049] The MPU 3 searches the correction table using the amount of change (impedance change) between the internal impedance acquired this time and the internal impedance acquired one interval before to acquire a voltage correction amount corresponding to the amount of change in impedance.The MPU 3 then corrects the cell voltage using the voltage correction amount.

[0050] When the temperature correction process of step S5 is completed, the entire process ends. On the other hand, if the determination of step S4 is "No", the MPU 3 ends the entire process without executing the temperature correction process of step S5.

[0051] The battery control device A of this embodiment detects the temperatures of multiple voltage detection lines L0 to L4 connected to multiple battery cells in battery B as detection line temperatures, and is equipped with an MPU3 (temperature acquisition unit) that acquires the operating temperature of battery B as the detection line temperature.

[0052] According to this embodiment, the operating temperature of battery B is obtained as the detection line temperatures of multiple voltage detection lines L0 to L4, so it is possible to provide a battery control device A (temperature detection device) that can appropriately detect the detection line temperatures of multiple voltage detection lines L0 to L4.

[0053] In addition, in the battery control device A of this embodiment, the MPU3 (temperature acquisition unit) has, as its functions, an impedance acquisition unit that acquires the internal impedance of battery B based on the AC impedance method, and a temperature conversion unit that converts the internal impedance of battery B into the detection line temperatures of multiple voltage detection lines L0 to L4.

[0054] According to this embodiment, the detection line temperatures of the plurality of voltage detection lines L0 to L4 are obtained based on the AC impedance method, so that it is possible to appropriately detect the detection line temperatures of the plurality of voltage detection lines L0 to L4.

[0055] In addition, in the battery control device A according to this embodiment, the battery B is formed by connecting multiple battery modules M1 to M4 in series, and the MPU 3 (temperature acquisition unit) acquires the detection line temperatures of multiple voltage detection lines L0 to L4 for each of the battery modules M1 to M4. According to this embodiment, it is possible to acquire the detection line temperatures of the multiple voltage detection lines L0 to L4 more precisely.

[0056] In addition, the impedance acquisition unit in this embodiment includes a selection switch 1 that sequentially applies the AC waveform generated by the AC waveform generating circuit 2 to multiple battery modules M1 to M4 in a predetermined order, and acquires the internal impedance for each battery module M1 to M4 based on the response signals (module voltage detection signal and module current detection signal) obtained from the battery modules upon application of the AC waveform.

[0057] According to this embodiment, since the selection switch 1 is provided to sequentially apply an AC waveform to the plurality of battery modules M1 to M4, it is possible to acquire the detection line temperatures of the plurality of voltage detection lines L0 to L4 for the plurality of battery modules M1 to M4.

[0058] Furthermore, the battery control device A of this embodiment includes a temperature detection device that detects the detection line temperatures of the multiple voltage detection lines L0 to L4, and a voltage correction unit that corrects the cell voltages of the multiple battery cells that constitute the battery B based on the detection line temperatures of the multiple voltage detection lines L0 to L4 detected by the temperature detection device.

[0059] According to this embodiment, the operating temperature of battery B is obtained as the detection line temperatures of multiple voltage detection lines L0 to L4, so it is possible to provide a battery control device A (voltage detection device) that can appropriately detect the detection line temperatures of multiple voltage detection lines L0 to L4. [Explanation of symbols]

[0060] A Battery control device (temperature detection device, voltage detection device) B Battery k1, k2 common contact s0~s4 selection contacts M1~M4 Battery Modules 1 Selector switch 2 AC waveform generator circuit 3 MPU

Claims

1. A temperature detection device that detects temperatures of a plurality of voltage detection lines connected to a plurality of battery cells in a battery as detection line temperatures, A temperature detection device comprising a temperature acquisition unit that acquires the temperature of the battery as the detection line temperature.

2. The temperature acquisition unit an impedance acquisition unit that acquires the internal impedance of the battery based on an AC impedance method; The temperature detection device according to claim 1 , further comprising a temperature conversion unit that converts the internal impedance into the detection line temperature.

3. the battery is a plurality of battery modules connected in series, The temperature detection device according to claim 2 , wherein the temperature acquisition unit acquires the detection line temperature for each of the battery modules.

4. The temperature detection device according to claim 3, characterized in that the impedance acquisition unit includes a selection switch that sequentially applies AC waveforms to the plurality of battery modules in a predetermined order, and acquires the internal impedance for each battery module based on a response signal obtained from the battery module by applying the AC waveform.

5. The temperature detection device according to any one of claims 1 to 4, a voltage correction unit that corrects the cell voltages of the plurality of battery cells based on the detection line temperature detected by the temperature detection device; A voltage detection device comprising:

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