Battery impedance measuring device

Abstract

The purpose of the present invention is to evaluate a battery with high accuracy using a simple method. A control unit (12) executes each of operation in a first mode in which the operation of a first switch (SW1) corresponding to a first resonance circuit (Rs1) and the operation of a second switch (SW2) corresponding to a second resonance circuit (Rs2) are different, and operation in a second mode. The control unit (12) determines the internal impedance of a battery (10) on the basis of the damped oscillation waveform of the first resonance circuit (Rs1) when operating in the first mode, the damped oscillation waveform of the first resonance circuit (Rs1) when operating in the second mode, and the damped oscillation waveform of the second resonance circuit (Rs2) when operating in the second mode.

Description

Battery impedance measuring device

[0001] The present invention relates to a battery impedance measuring device, and more particularly to a device for measuring the internal impedance of a battery using a resonant circuit.

[0002] Electric vehicles and hybrid vehicles are equipped with rechargeable batteries (hereinafter simply referred to as batteries) that can be repeatedly charged and discharged. Solar power generation systems also have batteries to store the generated electrical energy. During the manufacturing process, these batteries are evaluated for their performance and for any defects. Evaluation indicators include, for example, internal impedance and metal deposition amount.

[0003] Regarding technologies for evaluating batteries, Patent Document 1 describes a technique for measuring changes in impedance in response to changes in frequency. Patent Document 2 describes a battery tester. In this battery tester, the voltage generated at both terminals of the battery by the alternating current supplied to the battery is measured, and the internal impedance of the battery is determined based on the alternating current and the measured voltage. Patent Document 3 describes a four-wire impedance measuring device having a pair of source terminals (current supply terminals) and sense terminals (voltage detection terminals) connected to the sample to be measured. The equivalent series resistance of a battery is described as the sample to be measured. Patent Document 4 describes a detection device for detecting the state of a lithium-ion secondary battery. This detection device has one or more resonant circuits that apply one or more specific frequency vibrations to a lithium-ion secondary battery, and includes a detection unit that measures the damping characteristics of one or more resonant currents and outputs them as detection signals. The detection device further includes a control unit that uses the damping characteristic detection signal obtained from the detection unit to detect at least one of lithium deposition and the presence of foreign metals inside the lithium-ion secondary battery.

[0004] Japanese Patent Publication No. 2018-179652, Japanese Patent Publication No. 2023-32275, Japanese Patent Publication No. 2006-322821, Japanese Patent Publication No. 2023-182, Japanese Patent Publication No. 2023-110285

[0005] Methods for measuring the internal impedance of a battery include determining the internal impedance from the relationship between the sinusoidal voltage applied to the battery and the sinusoidal current flowing through the battery, as described in Patent Documents 1 to 3. Furthermore, as described in Patent Document 3, there is a method to improve measurement accuracy by measuring the internal impedance of the battery after compensating for the contact resistance between the battery electrodes. However, these methods require a high-precision sinusoidal wave generator, which can make the measurement equipment complex.

[0006] The objective of this invention is to perform highly accurate evaluation of batteries using a simple method.

[0007] The battery impedance measuring device according to the present invention comprises: a plurality of resonant circuits through which a resonant current flows in a battery to be measured; a waveform acquisition unit that acquires a damped oscillation waveform of the current flowing through each of the resonant circuits; a control unit that determines the internal impedance of the battery based on the damped oscillation waveform acquired for each of the resonant circuits; and a switch controlled by the control unit and provided corresponding to each of the resonant circuits, the switch provided between the corresponding resonant circuit and the battery, wherein the control unit determines the internal impedance based on a plurality of damped oscillation waveforms for each of the resonant circuits acquired for a plurality of different combinations of switch operations.

[0008] In one embodiment, one end of each resonant circuit is individually in contact with the positive or negative electrode of the battery, and the control unit determines the contact resistance value between one end of each resonant circuit and the battery, in addition to the internal impedance, based on multiple damped oscillation waveforms for each resonant circuit obtained for multiple switching operations with different combinations of switch operations.

[0009] In one embodiment, the control unit obtains a composite time waveform by combining the damped oscillation waveforms for each of the resonant circuits, and determines the internal impedance based on the composite time waveform.

[0010] In one embodiment, the control unit determines the internal impedance based on the degree of attenuation of multiple damped oscillation waveforms for each resonant circuit, which are obtained for multiple different combinations of switch operations.

[0011] In one embodiment, the battery is supplied with a plurality of resonant circuits, including a first resonant circuit and a second resonant circuit, and the control unit performs first mode and second mode operations, respectively, in which the operation of a first switch corresponding to the first resonant circuit and the operation of a second switch corresponding to the second resonant circuit are different, and the internal impedance is determined based on the damped oscillation waveform of the first resonant circuit when operating in the first mode, the damped oscillation waveform of the first resonant circuit when operating in the second mode, and the damped oscillation waveform of the second resonant circuit when operating in the second mode.

[0012] In one embodiment, one end of the first resonant circuit and one end of the second resonant circuit are in contact with the positive or negative electrode of the battery, respectively, and the control unit determines, in addition to the internal impedance, the contact resistance between one end of the first resonant circuit and the battery and the contact resistance between one end of the second resonant circuit and the battery, based on the damped oscillation waveform of the first resonant circuit when operating in the first mode, the damped oscillation waveform of the first resonant circuit when operating in the second mode, and the damped oscillation waveform of the second resonant circuit when operating in the second mode.

[0013] In one embodiment, the control unit determines the internal impedance based on the damped oscillation waveform of the first resonant circuit when operating in the first mode, and the combined time waveform when operating in the second mode, which is a combined time waveform obtained by combining the damped oscillation waveform of the first resonant circuit and the damped oscillation waveform of the second resonant circuit.

[0014] In one embodiment, the control unit determines the internal impedance based on the degree to which the damped oscillation waveform of the first resonant circuit is attenuated and the degree to which the composite time waveform is attenuated when operating in the first mode.

[0015] In one embodiment, when the first switch corresponding to the first resonant circuit and the second switch corresponding to the second resonant circuit are in the off state, the first mode is an operation mode in which the first switch is turned on from off and the second switch is maintained off, and the second mode is an operation mode in which when the first switch is off and the second switch is on, the first switch is turned on from off and the second switch is maintained on.

[0016] In one embodiment, when the first switch corresponding to the first resonant circuit and the second switch corresponding to the second resonant circuit are in the off state, the first mode is an operation mode in which the first switch is turned on from off and the second switch is maintained off, and the second mode is an operation mode in which when the first switch is on and the second switch is off, the first switch is maintained on and the second switch is turned on from off.

[0017] According to the present invention, the battery can be evaluated with high accuracy by a simple method.

[0018] It is a diagram showing the main part of the impedance measuring device. It is a diagram showing an equivalent circuit for explaining the measurement principle. It is a diagram showing the state of the battery impedance measuring device in modes 1 to 4. Current I Ｌ１，ｍ１ It is a diagram showing the time waveform of. Current I Ｌ１，ｍ３ It is a diagram showing the time waveform of. Current I Ｌ２，ｍ３ It is a diagram showing the time waveform of. Current I Ｌ１，ｍ３ and I Ｌ２，ｍ３ It is a diagram showing the time waveform of the added current I Ｐ obtained by combining them. Current I Ｌ１，ｍ３ from I Ｌ２，ｍ３ It is a diagram showing the time waveform of the subtracted current I ＭThis is a diagram showing the time waveform. This is a diagram showing a first configuration example of the battery impedance measuring device. This is a diagram showing a first modified example of the battery impedance measuring device. This is a flowchart showing an example of the processing performed by the battery impedance measuring device. This is a diagram showing a second modified example of the battery impedance measuring device. This is a diagram showing a second configuration example of the battery impedance measuring device. This is a diagram showing the state in operating modes 5 to 8. This is a diagram showing the state in operating modes 9 to 12. This is a diagram showing the state in operating modes 13 to 16.

[0019] Embodiments of the present invention will be described with reference to the figures. The same reference numerals are used for identical components shown in multiple drawings, and their descriptions are simplified. Unless otherwise specified, terms indicating directions such as up, down, left, and right refer to directions in the drawings.

[0020] Figure 1 shows the main components (main parts) of a battery impedance measuring device 100 according to an embodiment of the present invention. The battery impedance measuring device 100 includes a first resonant circuit Rs1 and a first switch SW １ , second resonant circuit Rs2, second switch SW ２ , First positive terminal T １ｐ , second positive terminal T ２ｐ , first negative terminal T １ｎ , second negative terminal T ２ｎ The system also includes a control unit 12. The control unit 12 may be a processor, which is hardware that controls the battery impedance measuring device 100 by executing a program.

[0021] The battery 10 to be measured is detachably attached to the battery impedance measuring device 100. The positive electrode of the battery 10 to be measured is the first positive electrode terminal T １ｐ and the second positive terminal T ２ｐ It makes contact with the first negative terminal T. １ｎ and the second negative terminal T ２ｎ It is attached to the battery impedance measuring device 100 so as to make contact with it.

[0022] One end of the first resonant circuit Rs1 is connected to the first positive terminal T. １ｐ It is connected to the first switch SW, and the other end is connected to the first switch SW.１ It is connected to one end of the first switch SW. １ The other end is the first negative terminal T. １ｎ It is connected to the second resonant circuit Rs2. One end of the second resonant circuit Rs2 is connected to the second positive terminal T. ２ｐ It is connected to the second switch SW, and the other end is connected to the second switch SW. ２ It is connected to one end of the second switch SW. ２ The other end is the second negative terminal T. ２ｎ Connected.

[0023] The first resonant circuit Rs1 is composed of the first resonant inductor L ｒｅｓ１ , First resonant capacitor C ｒｅｓ１ and the first discharge resistor R ｒｅｓ１ It is equipped with the first resonant inductor L ｒｅｓ１ and the first resonant capacitor C ｒｅｓ１ These are connected in series. First resonant capacitor C ｒｅｓ１ and the first discharge resistor R ｒｅｓ１ These are connected in parallel. First discharge resistor R ｒｅｓ１ This includes the first resonant capacitor C ｒｅｓ１ When no DC voltage is applied to the first resonant capacitor C ｒｅｓ１ Electrical charge is discharged from it.

[0024] The second resonant circuit Rs2 is composed of the second resonant inductor L ｒｅｓ２ , second resonant capacitor C ｒｅｓ２ and the second discharge resistor R ｒｅｓ２ It is equipped with a second resonant inductor L ｒｅｓ２ and the second resonant capacitor C ｒｅｓ２ These are connected in series. Second resonant capacitor C ｒｅｓ２ and the second discharge resistor R ｒｅｓ２ These are connected in parallel. Second discharge resistor R ｒｅｓ２ This includes a second resonant capacitor C ｒｅｓ２ When no DC voltage is applied to the second resonant capacitor C ｒｅｓ２ Electrical charge is discharged from it.

[0025] The first discharge resistor R in this embodiment ｒｅｓ１ and the second discharge resistor R ｒｅｓ２ The resistance value is large enough that it does not contribute to the measurement of the internal impedance of the battery 10.

[0026] As described later, the battery impedance measuring device 100 is the first switch SW １ and second switch SW ２ The control unit 12 controls the flow of a damped oscillation current to the battery 10. The battery impedance measuring device 100 connects the battery 10 to the first resonant inductor L ｒｅｓ１ and the second resonant inductor L ｒｅｓ２ The damped oscillation current flowing through at least one of the components is measured, and the internal impedance of the battery 10 is measured based on the time waveform of the measured damped oscillation current.

[0027] Figure 2 shows an equivalent circuit illustrating the measurement principle of the internal impedance of the battery 10. The first discharge resistor R shown in Figure 1 ｒｅｓ１ and the second discharge resistor R ｒｅｓ２ This is not shown in the equivalent circuit of Figure 2. First discharge resistor R ｒｅｓ１ and the second discharge resistor R ｒｅｓ２ This is because the resistance value is large enough that it does not contribute to the measurement of the internal impedance of the battery 10.

[0028] In Figure 2, the battery 10 is connected in series with an internal inductor L ｂ , internal resistance R ｂ and voltage source V ｂ This is represented by the first positive terminal T. １ｐ The contact resistance between the battery 10 and the positive terminal is the contact resistance R. ｃ１ｐ As shown, the second positive terminal T ２ｐ The contact resistance between the battery 10 and the positive terminal is the contact resistance R. ｃ２ｐ It is shown as follows: First positive terminal T １ｐ Contact resistance R ｃ１ｐ Replaced with the second positive terminal T ２ｐ Contact resistance R ｃ２ｐ Because it was replaced, the first positive terminal T １ｐ and the second positive terminal T ２ｐ The dashed line indicates the contact resistance R. ｃ１ｐ This is the first resonant inductor L ｒｅｓ１ One end and the internal inductor L ｂ Connected between one end and the other, with contact resistance R ｃ２ｐ This is the second resonant inductor Lｒｅｓ２ is connected between one end thereof and one end of the internal inductor L ｂ .

[0029] The contact resistance between the first negative terminal T １ｎ and the negative electrode of the battery 10 is shown as contact resistance R ｃ１ｎ , and the contact resistance between the second negative terminal T ２ｎ and the negative electrode of the battery 10 is shown as contact resistance R ｃ２ｎ . The first negative terminal T １ｎ is replaced with contact resistance R ｃ１ｎ , and the second negative terminal T ２ｎ is replaced with contact resistance R ｃ２ｎ , so the first negative terminal T １ｎ and the second negative terminal T ２ｎ are shown by dashed lines. The contact resistance R ｃ１ｎ is connected between the lower end of the first switch SW １ and the negative electrode of the voltage source V ｂ , and the contact resistance R ｃ２ｎ is connected between the lower end of the second switch SW ２ and the negative electrode of the voltage source V ｂ .

[0030] In this embodiment, the respective resistance values of the contact resistances R ｃ１ｐ , R ｃ１ｎ , R ｃ２ｐ and R ｃ２ｎ are approximated as being equal and being R ｐ . Also, the inductance of the first resonance inductor L ｒｅｓ１ and the inductance of the second resonance inductor L ｒｅｓ２ are equal and are L ｒｅｓ . Also, the capacitance of the first resonance capacitor C ｒｅｓ１ and the capacitance of the second resonance capacitor C ｒｅｓ２ are equal and are C ｒｅｓ . The resistance value of the first discharge resistor R ｒｅｓ１ and the resistance value of the second discharge resistor R ｒｅｓ２ are equal and are R ｒｅｓ .

[0031] From the positive electrode of the voltage source V ｂ , the internal resistance R ｂ , the internal inductor L ｂ , the contact resistance Rｃ１ｐ , First resonant inductor L ｒｅｓ１ , First resonant capacitor C ｒｅｓ１ , 1st switch SW １ and contact resistance R ｃ１ｎ After that, voltage source V ｂ The current flowing through the first loop that returns to the negative terminal is current I. １ It is defined as follows.

[0032] Voltage source V ｂ From the positive terminal, internal resistance R ｂ , internal inductor L ｂ , contact resistance R ｃ２ｐ , second resonant inductor L ｒｅｓ２ , second resonant capacitor C ｒｅｓ２ , second switch SW ２ and contact resistance R ｃ２ｎ After that, voltage source V ｂ The current flowing through the second loop, which returns to the negative terminal, is current I. ２ It is defined as follows.

[0033] Contact resistance R ｃ１ｐ , First resonant inductor L ｒｅｓ１ , First resonant capacitor C ｒｅｓ１ , 1st switch SW １ , contact resistance R ｃ１ｎ , contact resistance R ｃ２ｎ , second switch SW ２ , second resonant capacitor C ｒｅｓ２ , second resonant inductor L ｒｅｓ２ and contact resistance R ｃ２ｐ The current flowing through the third loop, which passes through the following in order, is current I. ３ It is defined as follows.

[0034] current I １ and current I ３ The combined current flows from top to bottom in Figure 2 through the first resonant circuit Rs1. Current I ２ From current I ３ The current remaining after subtracting the above flows from top to bottom in Figure 2 through the second resonant circuit Rs2. Also, current I １ and current I ２ The combined current flows out from the negative terminal of the battery 10, through the inside of the battery 10, and out from the positive terminal of the battery 10.

[0035] Figure 3 shows the first switch SW １ and second switch SW ２ The state of the battery impedance measuring device 100 in relation to the operation of the first switch SW is shown. １ and second switch SW ２ Modes 1 through 4 are shown as operating modes. Mode 1 is the first switch SW １ and second switch SW ２ From a state where both are OFF, the first switch SW １ The second switch SW switches from off to on. ２ Mode 2 is the operating mode in which the first switch SW remains off. １ and second switch SW ２ From a state where both are OFF, the first switch SW １ The second switch SW remains off. ２ This is the operating mode where the switch changes from off to on. Mode 3 is the first switch SW １ The second switch SW is off. ２ From the state where it is ON, the first switch SW １ The second switch SW switches from off to on. ２ This is the operating mode in which the first switch SW remains ON. Mode 4 is the first switch SW １ The second switch SW is ON. ２ From the OFF state, the first switch SW １ The second switch SW remains ON. ２ This is the operating mode where it switches from off to on.

[0036] In this embodiment, the internal impedance of the battery 10 is measured by the operation of the battery impedance measuring device 100 in modes 1 and 3, or by the operation of the battery impedance measuring device 100 in modes 2 and 4. As described above, the contact resistance R ｃ１ｐ , R ｃ１ｎ , R ｃ２ｐ and R ｃ２ｎ (Hereinafter, contact resistance R ｃThe resistance values ​​of the elements are equal, and the element constants of each element in the first resonant circuit Rs1 are equal to the element constants of each element in the second resonant circuit Rs2. That is, the circuits in Figures 1 and 2 are symmetrical. Therefore, the current I in mode 1 and mode 3 is equal. １ , current I ２ and current I ３ And the current I in modes 2 and 4 ２ , current I １ and reverse polarity current -I ３ These are identical. Therefore, the operation in modes 1 and 3 is shown below.

[0037] In Mode 1 operation, the control unit 12 controls the first switch SW １ and second switch SW ２ From the OFF state, the first switch SW １ Turn on the second switch SW ２ Keep it off. Second switch SW ２ Because it remains off, the current I in the first loop １ Only the current flows, and the first resonant inductor L ｒｅｓ１ Current I flowing through Ｌ１，ｍ１ is current I １ This matches. Here, the subscripts "L1, m1" refer to the first resonant inductor L in the operation of mode 1. ｒｅｓ１ This means the current flowing through it. The same applies to the subscripts attached to each of the following variables. However, to clarify the notation, the subscript indicating the mode may be omitted.

[0038] Figure 4 shows the current I when the operation of mode 1 starts at time t = 0. Ｌ１，ｍ１ The time waveform is shown. As will be described later, current I Ｌ１，ｍ１ The time waveform is from the voltage source V ｂ Voltage V ｂａｔ , internal resistance R ｂ Resistance value R ｂａｔ , internal inductor L ｂ Inductance L ｂａｔ and contact resistance R ｃ Resistance value R ｐ This results in a damped oscillation waveform determined by the element constants of each element included in the first resonant circuit Rs1.

[0039] The control unit 12 controls the current I Ｌ１，ｍ１ The time t = t is when it reaches its maximum. １，ｍ１ and t ２，ｍ１ Current I Ｌ１，ｍ１ A value corresponding to the maximum value of (for example, current I) Ｌ１，ｍ１ The values ​​(proportional to the maximum value of) are V ｐ１，ｍ１ and V ｐ２，ｍ１ The control unit 12 measures as V ｐ１，ｍ１ and V ｐ２，ｍ１ The specific configuration for measuring the current I will be described later. The control unit 12 controls the current I according to (Equation 1). Ｌ１,ｍ１ Attenuation rate α １，ｍ１ We seek.

[0040]

[0041] In Mode 3 operation, the control unit 12 controls the first switch SW １ The second switch SW is off. ２ From the state where it is ON, the first switch SW １ Turn on the second switch SW ２ Keep it ON. (First switch SW) １ and second switch SW ２ Since both are turned on, the current I in the first loop １ , the current I of the second loop ２ and the current I of the third loop ３ The first resonant inductor L flows. ｒｅｓ１ Current I flowing through Ｌ１，ｍ３ is current I １ and I ３ This combines the two, and the second resonant inductor L ｒｅｓ２ Current I flowing through Ｌ２，ｍ３ is current I ２ From I ３ This will be the result after subtracting that amount.

[0042] Figures 5 to 8 show the time waveforms of each current when the operation of mode 3 starts at time t = 0. Figure 5 shows the first resonant inductor L in the operation of mode 3. ｒｅｓ１ Current I flowing through Ｌ１，ｍ３ The time waveform is shown. Figure 6 shows the second resonant inductor L in the operation of mode 3. ｒｅｓ２Current I flowing through Ｌ２，ｍ３ The time waveform is shown.

[0043] Figure 7 shows the combined time waveform, with current I Ｌ１，ｍ３ and I Ｌ２，ｍ３ The summation current I Ｐ The time waveform is shown. Figure 8 shows the combined time waveform of current I Ｌ１，ｍ３ From I Ｌ２，ｍ３ Subtracted current I Ｍ The time waveform is shown.

[0044] Adding current I Ｐ and subtract current I Ｍ The time waveform is from the voltage source V ｂ Voltage V ｂａｔ , internal resistance R ｂ Resistance value R ｂａｔ , internal inductor L ｂ Inductance L ｂａｔ and contact resistance R ｃ Resistance value R ｐ This results in a damped oscillation waveform determined by the element constants of each element included in the first resonant circuit Rs1 and the second resonant circuit Rs2, respectively.

[0045] The control unit 12 controls the summing current I Ｐ = I Ｌ１ +I Ｌ２ The time t = t is when it reaches its maximum. １，Ｐ and t ２，Ｐ Adding current I Ｐ A value corresponding to the maximum value (for example, the summing current I Ｐ The values ​​(proportional to the maximum value of) are V ｐ１，Ｐ and V ｐ２，Ｐ The control unit 12 measures as V ｐ１，Ｐ and V ｐ２，Ｐ The specific configuration for obtaining this will be described later. The control unit 12 adds the current I according to (Equation 2). Ｐ Attenuation rate α １，ｍ３ We seek.

[0046]

[0047] Furthermore, the control unit 12 controls the subtraction current I Ｍ = I Ｌ１ -I Ｌ２ The time t = t is when it reaches its maximum.１，Ｍ and t ２，Ｍ Subtraction current I Ｍ A value corresponding to the maximum value (for example, subtraction current I Ｍ The values ​​(proportional to the maximum value of) are V ｐ１，Ｍ and V ｐ２，Ｍ The control unit 12 measures as V ｐ１，Ｍ and V ｐ２，Ｍ The specific configuration for obtaining this will be described later. The control unit 12 subtracts current I according to (Equation 3). Ｍ Attenuation rate α ２，ｍ３ We seek.

[0048]

[0049] The control unit 12 determines the attenuation rate α according to (Equation 1) to (Equation 3). １，ｍ１ , α １，ｍ３ and α ２，ｍ３ The internal impedance of the battery 10 is determined by applying the following equations (4) to (6). That is, the control unit 12 determines the internal resistance value R of the battery 10 based on equations (4) to (6). ｂａｔ , contact resistance R ｃ Resistance value R ｐ and internal inductance L ｂａｔ We will find the answer. The derivations of (Equation 4) to (Equation 6) will be described later.

[0050]

[0051] Here, L ｒｅｓ This is the first resonant inductor L ｒｅｓ１ and the second resonant inductor L ｒｅｓ２ This is the inductance, and in this embodiment, it is a known value. Thus, in the battery impedance measuring device 100 according to this embodiment, the control unit 12 operates in mode 1 and controls the first resonant inductor L ｒｅｓ１ Current I flowing through Ｌ１ Measure, current I Ｌ１ Attenuation rate α １，ｍ１ The control unit 12 also determines the first resonant inductor L in mode 3 operation. ｒｅｓ１ Current I flowing through Ｌ１ and the second resonant inductor L ｒｅｓ２Current I flowing through Ｌ２ The control unit 12 further calculates the added current I Ｐ = I Ｌ１ +I Ｌ２ Attenuation rate α １，ｍ３ To find the subtracted current I Ｍ = I Ｌ１ -I Ｌ２ Attenuation rate α ２，ｍ３ We seek.

[0052] The control unit 12 controls the attenuation rate α １，ｍ１ , α １，ｍ３ and α ２，ｍ３ Applying this to the above equations (4) to (6), we obtain the internal resistance value R of battery 10. ｂａｔ , contact resistance R ｃ Resistance value R ｐ and the internal inductance L of the battery 10 ｂａｔ Determine the constants (R) of the battery 10. ｂ and L ｂ ) is the voltage source V of battery 10 ｂ The measurement is performed using this method, and does not require an AC power supply or the like. Therefore, the battery 10 can be evaluated with high accuracy using a simple method.

[0053] Next, the derivation process of (Equations 4) to (Equations 6) is shown. In Mode 1 operation, the first resonant inductor L ｒｅｓ１ Current I flowing through Ｌ１，ｍ１ It can be expressed by (number 7) to (number 10).

[0054]

[0055] Here, A １，ｍ１ is the voltage V ｂａｔ , capacitance C ｒｅｓ , inductance L ｒｅｓ Internal inductance L ｂａｔ and internal resistance value R ｂａｔ It is expressed as a constant that does not depend on time t, where V is the voltage. ｂａｔ The voltage source V in battery 10 ｂ This is the output voltage. Capacitance C ｒｅｓ This is the first resonant capacitor C ｒｅｓ１ and the second resonant capacitor C ｒｅｓ２This is the capacitance. Inductance L ｒｅｓ This is the first resonant inductor L ｒｅｓ１ and the second resonant inductor L ｒｅｓ２ This is the inductance.

[0056] Next, the operation in mode 3 is shown. In the operation of mode 3, the first resonant inductor L ｒｅｓ１ Current I flowing through Ｌ１，ｍ３ This is expressed by (number 11) to (number 15).

[0057]

[0058] Here, if the design is such that both (Equation 16) and (Equation 17) hold true, then (Equation 18) will also hold true.

[0059]

[0060] Each constant of battery 10 can be determined for the frequency obtained by dividing the angular frequency shown in (Equation 18) by 2π.

[0061] In Mode 3 operation, the second resonant inductor L ｒｅｓ２ Current I flowing through Ｌ２，ｍ３ This is represented by (number 19).

[0062]

[0063] First resonant inductor L ｒｅｓ１ Current I flowing through Ｌ１，ｍ３ And the second resonant inductor L ｒｅｓ２ Current I flowing through Ｌ２，ｍ３ The summation current I Ｐ It is expressed as (Equation 20). Also, the first resonant inductor L ｒｅｓ１ Current I flowing through Ｌ１，ｍ３ Therefore, the second resonant inductor L ｒｅｓ２ Current I flowing through Ｌ２，ｍ３ Subtracted current I Ｍ It can be expressed as (number 21).

[0064]

[0065] L ｂａｔ ≪L ｒｅｓ L ｒｅｓ By designing this, (equation 22) holds true.

[0066]

[0067] From (Equation 8), (Equation 12), and (Equation 22), (Equations 4) to (Equation 6) are derived. (Equations 4) to (Equation 6) represent the attenuation rate α １，ｍ１ , α １，ｍ３ , α ２，ｍ３ and inductance L ｒｅｓ From there, the internal resistance R of the battery 10 is ｂａｔ , contact resistance R ｃ Resistance value R ｐ and the internal inductance L of the battery 10 ｂａｔ This is the formula for finding [the value].

[0068] Figure 9 shows a battery impedance measuring device 102 as a first configuration example of the battery impedance measuring device 100. The battery impedance measuring device 102 includes a first resonant circuit Rs1 and a first switch SW １ , second resonant circuit Rs2 and second switch SW ２ In addition to the control unit 12, the first pickup inductor L ｐｉｃｋ１ , first buffer amplifier 14, second pickup inductor L ｐｉｃｋ２ It includes a second buffer amplifier 16, an adder circuit 18, a subtractor circuit 20, a selector circuit 22, and a peak hold circuit 24.

[0069] First pickup inductor L ｐｉｃｋ１ This is the first resonant inductor L ｒｅｓ１ It connects to the first pickup inductor L. ｐｉｃｋ１ Both ends of the first buffer amplifier 14 are connected to the positive-phase terminal Tp and the negative-phase terminal Tn, which are a pair of input terminals of the first buffer amplifier 14. The output terminal of the first buffer amplifier 14 is connected to the adder circuit 18, the subtractor circuit 20, and the selector circuit 22.

[0070] First pickup inductor L ｐｉｃｋ１ At both ends are the first resonant inductor Lｒｅｓ１ A damped oscillation voltage appears corresponding to the damped oscillation current flowing through it. First pickup inductor L ｐｉｃｋ１ The phase of the damped oscillation voltage appearing at both ends of the first resonant inductor L ｒｅｓ１ Even if the phase of the damped oscillation current flowing through is different from that of the current I, the damping rate is still the same. Ｌ１ This will be equivalent to the value. The first buffer amplifier 14 outputs a signal SIL1 corresponding to this damped oscillation voltage. Signal SIL1 is the first resonant inductor L ｒｅｓ１ Current I flowing through Ｌ１ It has a damped vibration waveform equivalent to that of [another instrument].

[0071] Second pickup inductor L ｐｉｃｋ２ This is the second resonant inductor L ｒｅｓ２ It connects to the second pickup inductor L. ｐｉｃｋ２ Both ends of the wire are connected to the positive-phase terminal Tp and the negative-phase terminal Tn, which are a pair of input terminals of the second buffer amplifier 16. The output terminal of the second buffer amplifier 16 is connected to the adder circuit 18, the subtractor circuit 20, and the selector circuit 22.

[0072] Second pickup inductor L ｐｉｃｋ２ At both ends are the second resonant inductors L ｒｅｓ２ A damped oscillation voltage appears corresponding to the damped oscillation current flowing through it. Second pickup inductor L ｐｉｃｋ２ The phase of the damped oscillation voltage appearing at both ends of the second resonant inductor L ｒｅｓ２ Even if the phase of the damped oscillation current flowing through is different from that of the current I, the damping rate is still the same. Ｌ２ This results in a value equivalent to the above. The second buffer amplifier 16 outputs a signal SIL2 corresponding to this damped oscillation voltage. The signal SIL2 is controlled by the second resonant inductor L ｒｅｓ２ Current I flowing through Ｌ２ It has a damped vibration waveform equivalent to that of [another instrument].

[0073] The adder circuit 18 outputs a signal SIP to the selector circuit 22, which is the sum of the signal SIL1 output from the first buffer amplifier 14 and the signal SIL2 output from the second buffer amplifier 16. The subtractor circuit 20 outputs a signal SIM to the selector circuit 22, which is the subtraction of the signal SIL2 output from the second buffer amplifier 16 from the signal SIL1 output from the first buffer amplifier 14.

[0074] The selector circuit 22 selects one of the output terminals of the first buffer amplifier 14, the second buffer amplifier 16, the summing circuit 18, or the subtraction circuit 20, according to the control of the control unit 12, and connects the selected output terminal to the input terminal of the peak hold circuit 24.

[0075] The peak hold circuit 24 acquires two local maximums that occur at different times for the signal Sout output from the selector circuit 22 and outputs them to the control unit 12. The peak hold circuit 24 may be configured, for example, according to the technology described in Patent Document 5. The control unit 12 determines the attenuation rate of the signal Sout. The attenuation rate is the local maximum V acquired at the later time t2. ｐ２ The maximum value V obtained at the previous time t1 for this purpose. ｐ１ The natural logarithm of the ratio, with a time difference of t. ２ -t １ It is the value obtained by dividing by [a certain factor].

[0076] The operation of the battery impedance measuring device 102 will be explained. In operation mode 1, the control unit 12 first switches the first switch SW １ and second switch SW ２ Turn both of them off, and switch SW １ Switch the second switch SW from off to on. ２ Keep it turned off.

[0077] The control unit 12 controls the selector circuit 22 so that the output terminal of the first buffer amplifier 14 is connected to the peak hold circuit 24. With the output terminal of the first buffer amplifier 14 connected to the peak hold circuit 24, the control unit 12 performs operation in mode 1 and, based on the two maximum values ​​output from the peak hold circuit 24, determines the attenuation rate α １，ｍ１ We seek.

[0078] The control unit 12 controls the selector circuit 22 so that the output terminal of the adder circuit 18 is connected to the peak hold circuit 24. With the output terminal of the adder circuit 18 connected to the peak hold circuit 24, the control unit 12 performs operation in mode 3 and, based on the two maximum values ​​output from the peak hold circuit 24, determines the attenuation rate α １，ｍ３ We seek.

[0079] The control unit 12 controls the selector circuit 22 so that the output terminal of the subtraction circuit 20 is connected to the peak hold circuit 24. With the output terminal of the subtraction circuit 20 connected to the peak hold circuit 24, the control unit 12 performs operation in mode 3 and, based on the two maximum values ​​output from the peak hold circuit 24, determines the attenuation rate α ２，ｍ３ We seek.

[0080] The control unit 12 receives the attenuation rate α from the peak hold circuit 24. １，ｍ１ , α １，ｍ３ and α ２，ｍ３ Obtain the following, and based on (Equation 4) to (Equation 6) above, determine the internal resistance value R of the battery 10. ｂａｔ , contact resistance R ｃ Resistance value R ｐ and the internal inductance L of the battery 10 ｂａｔ We seek.

[0081] Figure 10 shows a battery impedance measuring device 104 as a first modified example of the battery impedance measuring device 102 in Figure 9. The battery impedance measuring device 104 is modified by replacing the first buffer amplifier 14 and the second buffer amplifier 16 of the battery impedance measuring device 102 in Figure 9 from differential (balanced) types to unbalanced types. The input terminal of the first buffer amplifier 14S is connected to the first resonant inductor L ｒｅｓ１ and the first resonant capacitor C ｒｅｓ１ It is connected to the connection point of the second buffer amplifier 16S. ｒｅｓ２ and the second resonant capacitor C ｒｅｓ２ It is connected to the connection point. The first buffer amplifier 14S has a first resonant inductor L ｒｅｓ１ Current I Ｌ１A voltage corresponding to the input is applied to the second buffer amplifier 16, and the second resonant inductor L ｒｅｓ２ Current I Ｌ２ A voltage corresponding to the value is input.

[0082] The control unit 12 of the battery impedance measuring device 104 performs the same operation as the control unit 12 of the battery impedance measuring device 102 in Figure 6, and measures the internal resistance R of the battery 10. ｂａｔ , contact resistance R ｃ Resistance value R ｐ and the internal inductance L of the battery 10 ｂａｔ We seek.

[0083] Figure 11 shows a flowchart illustrating an example of the processes performed by the battery impedance measuring devices 102 and 104. The control unit 12 first switches SW １ and second switch SW ２ The device is turned off (S1). In this state, the battery 10 is installed in the battery impedance measuring device (102, 104) (S2).

[0084] The control unit 12 determines whether the operating mode is mode 1 or mode 3 according to user operation or a predetermined program (S3). When the control unit 12 determines that it should operate in mode 1, it switches the first switch SW １ The circuit is turned on (S4), and the maximum value is obtained from the peak hold circuit 24 (S5).

[0085] The control unit 12 controls the first switch SW １ The control unit turns off (S6) and determines whether two local maximums were obtained at two different times (S7). If the control unit 12 determines that two local maximums were not obtained, it returns to step S4. If the control unit 12 determines that two local maximums were obtained, it determines whether operation in two operating modes was performed (S8). If the control unit 12 determines that operation in two operating modes was not performed, it returns to step S3.

[0086] If the control unit 12 determines in step S3 that it should operate in mode 3, then the second switch SW ２ Turn it on (S9), then switch the first switch SW １The control unit 12 turns on the first switch SW １ The control unit turns off (S12) and determines whether two local maximums have been obtained for each of the signals SIP and SIM at two different times (S13). If the control unit 12 determines that two local maximums have not been obtained for each of the signals SIP and SIM, it returns to step S10. If the control unit 12 determines that two local maximums have been obtained, it turns off the second switch SW ２ Turn it off (S14) and proceed to step S8.

[0087] If the control unit 12 determines in step S8 that operation in both operating modes has occurred, it calculates the internal impedance of the battery 10 (S15). After that, the battery 10 is removed from the battery impedance measuring device (102, 104), and the measurement is completed. If the control unit 12 determines that operation in both operating modes has not occurred, it returns to step S3.

[0088] This section describes the processing when using a combination of modes 1 and 3. When using a combination of modes 2 and 4, processing is performed on the operating modes and switches specified by the numbers in parentheses in the flowchart of Figure 11.

[0089] Figure 12 shows a battery impedance measuring device 106 as a second modification of the battery impedance measuring device 102 in Figure 9. The first pickup inductor L ｐｉｃｋ１ and the second pickup inductor L ｐｉｃｋ２ Each of these is the first resonant inductor L ｒｅｓ１ and the second resonant inductor L ｒｅｓ２ It connects to both of them.

[0090] First pickup inductor L ｐｉｃｋ１ and the first resonant inductor L ｒｅｓ１ The polarity of the coupling coefficient with current I Ｌ１ When the first pickup inductor L increases, ｐｉｃｋ１The voltage applied to the first buffer amplifier 14 is set to be positive. The first pickup inductor L ｐｉｃｋ１ and the second resonant inductor L ｒｅｓ２ The polarity of the coupling coefficient with current I Ｌ２ When the first pickup inductor L increases, ｐｉｃｋ１ The voltage applied to the first buffer amplifier 14 is set to be positive.

[0091] Second pickup inductor L ｐｉｃｋ２ and the first resonant inductor L ｒｅｓ１ The polarity of the coupling coefficient with current I Ｌ１ When the second pickup inductor L increases, ｐｉｃｋ２ The voltage applied to the second buffer amplifier 16 is set to be positive. Second pickup inductor L ｐｉｃｋ２ and the second resonant inductor L ｒｅｓ２ The polarity of the coupling coefficient with current I Ｌ２ When the second pickup inductor L increases, ｐｉｃｋ２ The voltage applied to the second buffer amplifier 16 is set to be negative.

[0092] Here, the voltages applied to the first buffer amplifier 14 and the second buffer amplifier 16 are the voltages at the positive-sequence terminal Tp, with the negative-sequence terminal Tn of the first buffer amplifier 14 and the second buffer amplifier 16 as the potential reference.

[0093] With this configuration, the first resonant inductor L ｒｅｓ１ Current I flowing through Ｌ１ and the second resonant inductor L ｒｅｓ２ Current I flowing through Ｌ２ A voltage corresponding to the combined current is output from the first buffer amplifier 14 as the first signal SA. Also, the first resonant inductor L ｒｅｓ１ Current I flowing through Ｌ１ From the second resonant inductor L ｒｅｓ２ Current I flowing through Ｌ２ A voltage corresponding to the current after subtracting the above is output from the second buffer amplifier 16 as the second signal SS.

[0094] The operation of the battery impedance measuring device 106 is shown below. The control unit 12 performs mode 1 operation with the output terminal of the first buffer amplifier 14 or the second buffer amplifier 16 connected to the peak hold circuit 24. From the output terminal of the first buffer amplifier 14, the first resonant inductor L ｒｅｓ１ Current I flowing through Ｌ１ A corresponding first signal SA is output to the peak hold circuit 24. The first resonant inductor L is also output from the output terminal of the second buffer amplifier 16. ｒｅｓ１ Current I flowing through Ｌ１ A second signal SS corresponding to this is output to the peak hold circuit 24. Based on the two maximum values ​​output from the peak hold circuit 24, the control unit 12 determines the attenuation rate α １，ｍ１ We seek.

[0095] The control unit 12 controls the selector circuit 22 so that the output terminal of the first buffer amplifier 14 is connected to the peak hold circuit 24. The control unit 12 performs mode 3 operation with the output terminal of the first buffer amplifier 14 connected to the peak hold circuit 24. From the output terminal of the first buffer amplifier 14, the first resonant inductor L ｒｅｓ１ Current I flowing through Ｌ１ and the second resonant inductor L ｒｅｓ２ Current I flowing through Ｌ２ A first signal SA corresponding to the combined current is output to the peak hold circuit 24. The control unit 12 determines the attenuation rate α based on the two maximum values ​​output from the peak hold circuit 24. １，ｍ３ We seek.

[0096] The control unit 12 controls the selector circuit 22 so that the output terminal of the second buffer amplifier 16 is connected to the peak hold circuit 24. The control unit 12 performs mode 3 operation with the output terminal of the second buffer amplifier 16 connected to the peak hold circuit 24. From the output terminal of the first buffer amplifier 14, the first resonant inductor L ｒｅｓ１ Current I flowing through Ｌ１ From the second resonant inductor L ｒｅｓ２ Current I flowing through Ｌ２A second signal SS corresponding to the current after subtracting is output to the peak hold circuit 24. The control unit 12 determines the attenuation rate α based on the two maximum values ​​output from the peak hold circuit 24. ２，ｍ３ We seek.

[0097] The control unit 12 receives the attenuation rate α from the peak hold circuit 24. １，ｍ１ , α １，ｍ３ and α ２，ｍ３ Obtain the following, and based on (Equation 4) to (Equation 6) above, determine the internal resistance value R of the battery 10. ｂａｔ , contact resistance R ｃ Resistance value R ｐ and the internal inductance L of the battery 10 ｂａｔ We seek.

[0098] Figure 13 shows a battery impedance measuring device 108 as a second configuration example of the battery impedance measuring device 100. In the battery impedance measuring device 108, the first capacitor switch block CS １ Next, the third capacitor switch block CS ３ These are connected in parallel. First capacitor switch block CS １ This is the first resonant capacitor C ｒｅｓ１ , first discharge resistance R ｒｅｓ１ and the first switch SW １ It is a component consisting of the following: Third capacitor switch block CS ３ This is the third resonant capacitor C ｒｅｓ３ , third discharge resistance R ｒｅｓ３ and the third switch SW ３ It is a component consisting of the following: Third resonant capacitor C ｒｅｓ３ and the third switch SW ３ These are connected in series, and the third resonant capacitor C ｒｅｓ３ and the third discharge resistor R ｒｅｓ３ They are connected in parallel.

[0099] Also, the second capacitor switch block CS ２ Next, the fourth capacitor switch block CS ４ These are connected in parallel. Second capacitor switch block CS ２ This is the second resonant capacitor C ｒｅｓ２, second discharge resistance R ｒｅｓ２ and second switch SW ２ It is a component consisting of the following: 4th capacitor switch block CS ４ This is the fourth resonant capacitor C ｒｅｓ４ , fourth discharge resistance R ｒｅｓ４ and the fourth switch SW ４ It is a component consisting of the following: Fourth resonant capacitor C ｒｅｓ４ and the 4th switch SW ４ These are connected in series, and the fourth resonant capacitor C ｒｅｓ４ and the fourth discharge resistor R ｒｅｓ４ They are connected in parallel.

[0100] As described above, the element constants of the first resonant circuit Rs1 and the element constants of the second resonant circuit Rs are the same. In this configuration example, the third resonant capacitor C ｒｅｓ３ The capacitance of and the fourth resonant capacitor C ｒｅｓ４ The capacitances are assumed to be the same. Furthermore, the third discharge resistance R ｒｅｓ３ The resistance value and the fourth discharge resistor R ｒｅｓ４ The resistance values ​​are also considered to be the same.

[0101] The battery impedance measuring device 108 in this configuration example operates in either frequency A operation or frequency B operation, which have different resonant frequencies. In frequency A operation, the first resonant capacitor C ｒｅｓ１ and the second resonant capacitor C ｒｅｓ２ This is used to measure the internal impedance of the battery 10. In B frequency operation, the third resonant capacitor C ｒｅｓ３ and the fourth resonant capacitor C ｒｅｓ４ This is used to measure internal impedance.

[0102] In A-frequency operation, the control unit 12 controls the third switch SW ３ and the fourth switch SW ４ Keep the first switch SW OFF. １ and second switch SW ２ The operation of either mode 1 or mode 3 is performed by switching. The control unit 12 controls the attenuation rate α for the resonant frequency in A frequency operation. １，ｍ１ , α １，ｍ３ and α２，ｍ３ The internal resistance value R of the battery 10 is obtained. ｂａｔ , contact resistance R ｃ Resistance value R ｐ and the internal inductance L of the battery 10 ｂａｔ We seek.

[0103] In B frequency operation, the control unit 12 controls the first switch SW １ and second switch SW ２ Keep the third switch SW OFF. ３ and the fourth switch SW ４ Switching of the first switch SW performs either mode 1 or mode 3 operation. That is, in A frequency operation, the first switch SW １ Similar to the operation of switching the third switch SW, the control unit 12 controls the third switch SW in B frequency operation. ３ Switches the second switch SW in A frequency operation. ２ Similar to the operation of switching the fourth switch SW, the control unit 12 controls the fourth switch SW in B frequency operation. ４ Switch between them.

[0104] The control unit 12 controls the attenuation rate α for the resonant frequency in B frequency operation. １，ｍ１ , α １，ｍ３ and α ２，ｍ３ The internal resistance value R of the battery 10 is obtained. ｂａｔ , contact resistance R ｃ Resistance value R ｐ and the internal inductance L of the battery 10 ｂａｔ We seek.

[0105] According to the battery impedance measuring device 108, the internal resistance value R of the battery 10 is determined for each of two different resonant frequencies. ｂａｔ , contact resistance R ｃ Resistance value R ｐ and the internal inductance L of the battery 10 ｂａｔ This is required.

[0106] In the battery impedance measuring devices 100, 102, 104, 106, and 108 according to embodiments of the present invention, the above describes the operation combining modes 1 and 3, and the operation combining modes 2 and 4. The internal impedance of the battery 10 may be measured by the operation combining modes 1 and 4, and the operation combining modes 2 and 3.

[0107] In operation combining modes 1 and 4, the polarity of the formula corresponding to (Equation 21) is reversed compared to operation combining modes 1 and 3, but (Equations 4) to (Equations 6) are still used. Similarly, in operation combining modes 2 and 3, the polarity of the formula corresponding to (Equation 21) is reversed compared to operation combining modes 2 and 4, but (Equations 4) to (Equations 6) are still used.

[0108] Furthermore, in addition to modes 1 to 4, modes 5 to 16 shown in Figures 14A to 14C are also possible operating modes for the battery impedance measuring devices 100, 102, 104, 106 and 108 according to the embodiment of the present invention. Of these operating modes, modes 5 to 7, 10, and 12 to 16 cannot be used to measure the internal impedance of the battery 10 because no current flows through the first resonant circuit Rs1 and the second resonant circuit Rs2.

[0109] Mode 8 may be used in place of Mode 1 or 2. Here, current I １，ｍ８ and current I ２，ｍ８ They are equal, and the decay rate corresponding to (Equation 8) is given by (Equation 22).

[0110]

[0111] Furthermore, mode 9 may be used in place of mode 1, and mode 11 may be used in place of mode 2.

[0112] As described above, the battery impedance measuring device (100, 102, 104, 106, 108) according to the embodiment of the present invention includes a first resonant circuit Rs1 and a second resonant circuit Rs2 as a plurality of resonant circuits that supply a resonant current to the battery 10 to be measured.

[0113] The peak hold circuit 24 acquires the damped oscillation waveforms of the currents flowing through the first resonant circuit Rs1 and the second resonant circuit Rs2, and obtains the maximum values ​​at different times. The control unit 12 determines the internal impedance of the battery 10 based on the maximum values ​​at different times of the damped oscillation waveforms of the currents flowing through the first resonant circuit Rs1 and the second resonant circuit Rs2.

[0114] In this way, the peak hold circuit 24, which acts as a waveform acquisition unit, acquires the damped oscillation waveform of the current flowing through each resonant circuit, and the control unit 12 determines the internal impedance of the battery 10 based on the damped oscillation waveform acquired for each resonant circuit.

[0115] The battery impedance measuring devices (100, 102, 104, 106, 108) are provided to correspond to multiple (two) resonant circuits and are controlled by the control unit 12, with the first switch SW being a switch. １ and second switch SW ２ It is equipped with the following: The battery impedance measuring device (100, 102, 104, 106, 108) is equipped with the first switch SW which is provided in correspondence with the first resonant circuit Rs1. １ And the second switch SW provided for the second resonant circuit Rs2 ２ It is equipped with the first switch SW １ It is provided between the first resonant circuit Rs1 and the battery 10, and the second switch SW ２ It is provided between the second resonant circuit Rs2 and the battery 10.

[0116] The control unit 12 determines the internal impedance of the battery 10 based on multiple damped oscillation waveforms for each resonant circuit, which are acquired in response to multiple different combinations of switch operations. In the battery impedance measuring device (100, 102, 104, 106, 108) according to the embodiment of the present invention, the combination of switch operations may be a combination of modes 1 and 3, or a combination of modes 2 and 4. Mode 8 may be used instead of mode 1 or 2. Mode 9 may be used instead of mode 1, and mode 11 may be used instead of mode 2.

[0117] The control unit 12 may determine multiple internal impedances of the battery 10 for multiple different combinations of switch operation. The control unit 12 determines multiple internal resistance values ​​R for multiple different combinations of switch operation. ｂａｔ The mean, median, mode, and other statistical values ​​are used to determine the final internal resistance value R. ｂａｔ The control unit 12 can determine the multiple resistance values ​​R obtained for multiple combinations of different switch operations. ｐ The statistical value of the final contact resistance R ｃ The control unit 12 can determine the multiple internal inductances L obtained for multiple combinations of different switch operations. ｂａｔ The statistical value of the final internal inductance L ｂａｔ You can calculate it as follows.

[0118] In the battery impedance measuring device (100, 102, 104, 106, 108) according to the embodiment of the present invention, one end of each resonant circuit is individually in contact with the positive or negative electrode of the battery 10. One end of the first resonant circuit Rs1 is connected to the first positive electrode terminal T １ｐ And the first switch SW １ The end opposite to the first resonant circuit Rs1 is the first negative terminal T. １ｎ Therefore, one end of the second resonant circuit Rs2 is connected to the second positive terminal T. ２ｐ And the second switch SW ２ The end opposite to the second resonant circuit Rs2 is the second negative terminal T. ２ｎ The positive terminal of battery 10 is the first positive terminal T. １ｐ and the second positive terminal T ２ｐ The negative terminal of battery 10 makes contact with the second negative terminal T. ２ｎ and the second negative terminal T ２ｎ It makes contact with the terminal. This allows the internal impedance of the battery 10 to be measured based on the four-terminal method.

[0119] Based on multiple damped oscillation waveforms for each resonant circuit obtained for multiple different combinations of switch operations, the control unit 12 calculates the contact resistance R as the contact resistance value between one end of each resonant circuit and the battery 10, in addition to the internal impedance, based on the multiple damped oscillation waveforms obtained for each resonant circuit for multiple different combinations of switch operations. ｃ Resistance value R ｐ We seek.

[0120] The control unit 12 obtains a combined time waveform by synthesizing the damped oscillation waveforms for each resonant circuit, and determines the internal impedance of the battery 10 based on the combined time waveform. The combined time waveform includes the first resonant inductor L ｒｅｓ１ Current I flowing through Ｌ１ and the second resonant inductor L ｒｅｓ２ Current I flowing through Ｌ２ The time waveform of the combined current, and current I Ｌ１ From current I Ｌ２ There is a time waveform of the current after subtracting [a certain factor].

[0121] The control unit 12 determines the internal impedance of the battery 10 based on the degree of attenuation of multiple damped oscillation waveforms for each resonant circuit, which are obtained for multiple different combinations of switch operations. The attenuation rate shown in (Equation 1) to (Equation 3) is used as the degree of attenuation of the damped oscillation waveform.

[0122] The control unit 12 controls the first switch SW corresponding to the first resonant circuit Rs1. １ The operation of the second switch SW corresponding to the second resonant circuit Rs2 ２ The control unit 12 performs first and second modes of operation, which are different from the operation of the first mode. Based on the damped oscillation waveform of the first resonant circuit Rs1 when operating in first mode, the damped oscillation waveform of the first resonant circuit Rs1 when operating in second mode, and the damped oscillation waveform of the second resonant circuit Rs2 when operating in second mode, the control unit 12 determines the internal impedance of the battery 10.

[0123] The first mode and the second mode may be mode 1 and mode 3, respectively. Alternatively, the first mode and the second mode may be mode 2 and mode 4, respectively.

[0124] The first mode and the second mode may be mode 1 and mode 4, respectively. Alternatively, the first mode and the second mode may be mode 2 and mode 3, respectively.

[0125] Mode 8 may be used instead of Mode 1 or 2. Also, Mode 9 may be used instead of Mode 1, and Mode 11 may be used instead of Mode 2.

[0126] [Configuration of the present invention] Configuration 1: A battery impedance measuring device comprising: a plurality of resonant circuits that pass a resonant current through a battery to be measured; a waveform acquisition unit that acquires a damped vibration waveform of the current flowing through each of the resonant circuits; a control unit that determines the internal impedance of the battery based on the damped vibration waveform acquired for each of the resonant circuits; and a switch controlled by the control unit and provided corresponding to each of the resonant circuits, the switch provided between the corresponding resonant circuit and the battery, wherein the control unit determines the internal impedance based on a plurality of damped vibration waveforms for each of the resonant circuits acquired for a plurality of different combinations of switch operations. Configuration 2: The battery impedance measuring device according to Configuration 1, wherein one end of each of the resonant circuits is individually in contact with the positive or negative electrode of the battery, and the control unit determines, in addition to the internal impedance, the contact resistance value between one end of each of the resonant circuits and the battery based on a plurality of damped vibration waveforms for each of the resonant circuits acquired for a plurality of different combinations of switch operations. Configuration 3: A battery impedance measuring device according to Configuration 1 or Configuration 2, wherein the control unit obtains a composite time waveform by synthesizing the damped vibration waveforms for each of the resonant circuits, and determines the internal impedance based on the composite time waveform. Configuration 4: A battery impedance measuring device according to any one of Configurations 1 to 3, wherein the control unit determines the internal impedance based on the degree of damping of multiple damped vibration waveforms for each of the resonant circuits, which are obtained for multiple switch operations with different combinations of operation for each of the switches.Configuration 5: A battery impedance measuring device as described in Configuration 1, comprising a first resonant circuit and a second resonant circuit as a plurality of resonant circuits through which a resonant current flows in the battery, wherein the control unit performs first mode and second mode operations, respectively, in which the operation of a first switch corresponding to the first resonant circuit and the operation of a second switch corresponding to the second resonant circuit are different, and determines the internal impedance based on the damped oscillation waveform of the first resonant circuit when operating in the first mode, the damped oscillation waveform of the first resonant circuit when operating in the second mode, and the damped oscillation waveform of the second resonant circuit when operating in the second mode. Configuration 6: A battery impedance measuring device according to Configuration 5, wherein one end of the first resonant circuit and one end of the second resonant circuit are individually in contact with the positive or negative electrode of the battery, and the control unit determines, in addition to the internal impedance, the contact resistance between one end of the first resonant circuit and the battery and the contact resistance between one end of the second resonant circuit and the battery, based on the damped vibration waveform of the first resonant circuit when operating in the first mode, the damped vibration waveform of the first resonant circuit when operating in the second mode, and the damped vibration waveform of the second resonant circuit when operating in the second mode. Configuration 7: A battery impedance measuring device according to Configuration 5 or Configuration 6, wherein the control unit determines the internal impedance based on the damped vibration waveform of the first resonant circuit when operating in the first mode and the combined time waveform when operating in the second mode, which is a combined time waveform obtained by combining the damped vibration waveform of the first resonant circuit and the damped vibration waveform of the second resonant circuit. Configuration 8: A battery impedance measuring device according to any one of Configurations 5 to 7, wherein the control unit determines the internal impedance based on the degree to which the damped oscillation waveform of the first resonant circuit is attenuated and the degree to which the composite time waveform is attenuated when operating in the first mode.Configuration 9: A battery impedance measuring device according to any one of Configurations 5 to 8, wherein the first mode is an operating mode in which, when the first switch corresponding to the first resonant circuit and the second switch corresponding to the second resonant circuit are in the off state, the first switch is turned on from off and the second switch is kept off, and the second mode is an operating mode in which, when the first switch is off and the second switch is on, the first switch is turned on from off and the second switch is kept on. Configuration 10: A battery impedance measuring device according to any one of Configurations 5 to 8, wherein the first mode is an operating mode in which, when the first switch corresponding to the first resonant circuit and the second switch corresponding to the second resonant circuit are in the off state, the first switch is turned on from off and the second switch is kept off, and the second mode is an operating mode in which, when the first switch is on and the second switch is off, the first switch is kept on and the second switch is turned on from off.

[0127] 10 Battery, 12 Control unit, 14, 14S, 16, 16S Buffer amplifier, 18 Adder circuit, 20 Subtractor circuit, 22 Selector circuit, 24 Peak hold circuit, 100, 102, 103, 104, 106, 108 Battery impedance measuring device, Rs1 First resonant circuit, Rs2 Second resonant circuit, SW １ Switch 1, SW ２ Second switch, SW ３ Third switch, SW ４ Fourth switch, L ｒｅｓ１ First resonant inductor, C ｒｅｓ１ First resonant capacitor, R ｒｅｓ１ First discharge resistance, L ｒｅｓ２ Second resonant inductor, C ｒｅｓ２ Second resonant capacitor, R ｒｅｓ２ Second discharge resistance, C ｒｅｓ３ Third resonant capacitor, R ｒｅｓ３ Third discharge resistance, C ｒｅｓ４Fourth resonant capacitor, R ｒｅｓ４ Fourth discharge resistance, T １ｐ First positive terminal, T ２ｐ Second positive terminal, T １ｎ First negative terminal, T ２ｎ Second negative terminal, R ｃ１ｐ , R ｃ１ｎ , R ｃ２ｐ , R ｃ２ｎ　 Contact resistance, L ｐｉｃｋ１ First pickup inductor, Lp ｉｃｋ２ Second pickup inductor, Tp positive phase terminal, Tn negative phase terminal, CS １ First capacitor switch block, CS ２ Second capacitor switch block, CS ３ Third capacitor switch block, CS ４ Fourth capacitor switch block.

Claims

1. A battery impedance measuring device comprising: a plurality of resonant circuits through which a resonant current flows in a battery to be measured; a waveform acquisition unit that acquires a damped oscillation waveform of the current flowing through each of the resonant circuits; a control unit that determines the internal impedance of the battery based on the damped oscillation waveform acquired for each of the resonant circuits; and a switch controlled by the control unit and provided corresponding to each of the resonant circuits, the switch provided between the corresponding resonant circuit and the battery, wherein the control unit determines the internal impedance based on a plurality of damped oscillation waveforms for each of the resonant circuits acquired for a plurality of different combinations of switch operations.

2. A battery impedance measuring device according to claim 1, wherein one end of each resonant circuit is individually in contact with the positive or negative electrode of the battery, and the control unit determines, in addition to the internal impedance, the contact resistance value between one end of each resonant circuit and the battery based on a plurality of damped oscillation waveforms for each resonant circuit obtained for a plurality of switch operations with different combinations of operation of each switch.

3. A battery impedance measuring device according to claim 1 or claim 2, wherein the control unit obtains a composite time waveform by synthesizing the damped oscillation waveforms for each of the resonant circuits, and determines the internal impedance based on the composite time waveform.

4. A battery impedance measuring device according to claim 1 or claim 2, wherein the control unit determines the internal impedance based on the degree of attenuation of multiple damped oscillation waveforms for each resonant circuit, which are obtained for multiple switch operations with different combinations of operation for each switch.

5. A battery impedance measuring device according to claim 1, comprising a first resonant circuit and a second resonant circuit as a plurality of resonant circuits through which a resonant current flows in the battery, wherein the control unit performs first mode and second mode operations, respectively, in which the operation of a first switch corresponding to the first resonant circuit and the operation of a second switch corresponding to the second resonant circuit are different, and determines the internal impedance based on the damped oscillation waveform of the first resonant circuit when operating in the first mode, the damped oscillation waveform of the first resonant circuit when operating in the second mode, and the damped oscillation waveform of the second resonant circuit when operating in the second mode.

6. A battery impedance measuring device according to claim 5, wherein one end of the first resonant circuit and one end of the second resonant circuit are individually in contact with the positive or negative electrode of the battery, and the control unit determines, in addition to the internal impedance, the contact resistance between one end of the first resonant circuit and the battery and the contact resistance between one end of the second resonant circuit and the battery, based on the damped oscillation waveform of the first resonant circuit when operating in the first mode, the damped oscillation waveform of the first resonant circuit when operating in the second mode, and the damped oscillation waveform of the second resonant circuit when operating in the second mode.

7. A battery impedance measuring device according to claim 5 or claim 6, wherein the control unit determines the internal impedance based on the damped oscillation waveform of the first resonant circuit when operating in the first mode, and the combined time waveform when operating in the second mode, which is a combined time waveform obtained by combining the damped oscillation waveform of the first resonant circuit and the damped oscillation waveform of the second resonant circuit.

8. A battery impedance measuring device according to claim 7, wherein the control unit determines the internal impedance based on the degree to which the damped oscillation waveform of the first resonant circuit is attenuated and the degree to which the composite time waveform is attenuated when it is operating in the first mode.

9. A battery impedance measuring device according to claim 5 or claim 6, wherein the first mode is an operating mode in which, when the first switch corresponding to the first resonant circuit and the second switch corresponding to the second resonant circuit are in the off state, the first switch is turned on from off and the second switch is kept in the off state, and the second mode is an operating mode in which, when the first switch is off and the second switch is on, the first switch is turned on from off and the second switch is kept in the on state.

10. A battery impedance measuring device according to claim 5 or claim 6, wherein the first mode is an operating mode in which, when the first switch corresponding to the first resonant circuit and the second switch corresponding to the second resonant circuit are in the off state, the first switch is turned on and the second switch is kept off, and the second mode is an operating mode in which, when the first switch is on and the second switch is off, the first switch is kept on and the second switch is turned on from off.

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