Method of measuring path resistance of circuit energizing secondary battery

Abstract

To evaluate electrical resistance of a path energizing a battery more accurately.SOLUTION: A method of measuring path resistance of a circuit energizing a battery is provided. The method includes: a step (i) of, by using a first path connected to one electrode of the battery and second and third paths connected to the other electrode, (a) energizing a circuit series connected to the first path, the battery and the second path to obtain total voltage value including voltage of the battery and voltage drop generated in the first and second paths, (b) energizing a circuit series connected to the first path, the battery and the third path to obtain total voltage value including voltage of the battery and voltage drop generated in the first and third paths, and (c) energizing a circuit series connected to the second path and the third path to obtain total voltage value including voltage drop generated in the second and third paths; and a step (ii) of calculating resistance values of the second path and / or the third path on the basis of each current value and each total voltage value.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present application relates to a method for charging a secondary battery, and more particularly to a method for measuring a path resistance in a circuit that energizes a secondary battery. [Background technology]

[0002] Regarding the charging and discharging of secondary batteries, Patent Document 1 describes "a charge and discharge inspection system comprising a power source for supplying power to a secondary battery and a battery measurement unit for measuring the voltage across the secondary battery and the charging current for inspection, the charge and discharge inspection system further comprising a calculation unit for calculating the resistance value of the charging path based on the voltage across the secondary battery, the charging current and the output voltage of the power source." [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-180109 Summary of the Invention [Problem to be solved by the invention]

[0004] However, if the point where the voltage is measured is part of the current path, the voltage drop caused by the electrical resistance (parasitic resistance) of the current path when the battery is charged or discharged will be added to the battery voltage that is measured, making it impossible to accurately determine the battery voltage while current is flowing.

[0005] The present invention provides a method for measuring path resistance that can more accurately evaluate the electrical resistance of a path through which current flows in a battery, a method for inspecting charge and discharge of a battery, a method for charging a battery, and a method for manufacturing a battery. [Means for solving the problem]

[0006] In a first embodiment, there is provided a method for measuring the path resistance of a circuit that energizes a battery, the battery comprising a first electrode having a first polarity and a second electrode having a second polarity opposite to the first polarity, the method including: (i) using a first path connected to the first electrode of the battery and having a first resistance value, a second path connected to the second electrode of the battery and having a second resistance value, and a third path connected to the second electrode of the battery and having a third resistance value, the method comprising: (a) applying a current at a first current value to a first circuit in which the first path, the battery, and the second path are connected in series in this order, thereby obtaining a first total voltage value including the voltage of the battery, a voltage drop occurring in the first path, and a voltage drop occurring in the second path; (b) measuring the path resistance of the first path, the battery, and the third path; a second circuit in which the first and second paths are connected in series in this order, thereby obtaining a second total voltage value including the voltage of the battery, a voltage drop occurring in the first path, and a voltage drop occurring in the third path; and a third circuit in which the second and third paths are electrically connected in series, thereby obtaining a third total voltage value including the voltage drop occurring in the second path and a voltage drop occurring in the third path. The method for measuring path resistance includes the steps of: (a) applying a current at a second current value to a second circuit in which the first and second paths are connected in series in this order, thereby obtaining a third total voltage value including the voltage drop occurring in the second path and a voltage drop occurring in the third path; and (b) calculating the second resistance value and / or the third resistance value based on the first current value, the second current value, and the third current value, as well as the first total voltage value, the second total voltage value, and the third total voltage value.

[0007] In a second embodiment, there is provided a method for inspecting charge and discharge of a battery, the method including: (i) measuring a path resistance of a circuit that conducts current to a battery by the method of the first embodiment; and (ii) inspecting the charging and / or discharging of the battery using the circuit based on the value of the path resistance measured in step (i).

[0008] In a third embodiment, there is provided a method for charging a battery, comprising: (i) measuring a path resistance of a circuit that charges a battery by the method of the first embodiment; and (ii) charging the battery using the circuit based on the value of the path resistance measured in step (i).

[0009] In a fourth embodiment, there is provided a method of manufacturing a battery, comprising the steps of assembling a battery and charging the battery by the method of the third embodiment. [Effects of the Invention]

[0010] According to the first embodiment of the present invention, by differentiating the current paths between the current-carrying point and the voltage measurement point, a method for measuring path resistance can be provided that can more accurately evaluate the electrical resistance of the path through which current flows in a battery. According to the second embodiment of the present invention, a battery charge / discharge inspection method can be provided that can more accurately evaluate the state of charge of a battery because the electrical resistance of the current-carrying path is measured using the method of the first embodiment. According to the third embodiment of the present invention, a battery charging method can be provided that can more accurately determine the state of the battery during charging because the battery is charged based on the path resistance value determined using the method of the first embodiment. According to the fourth embodiment of the present invention, a battery manufacturing method can be provided that can more accurately adjust the state of charge of the manufactured battery because the battery is charged using the method of the third embodiment. [Brief explanation of the drawings]

[0011] [Figure 1] Fig. 1(A) is a flowchart illustrating a path resistance measurement method S10 according to one embodiment. Fig. 1(B) to (D) are circuit diagrams illustrating a circuit used in the measurement method S10 and the state of the circuit during each measurement. [Figure 2] Fig. 2(A) is a flowchart illustrating a path resistance measurement method S20 according to another embodiment. Fig. 2(B) to (D) are circuit diagrams illustrating a circuit used in the measurement method S20 and the state of the circuit in each measurement. [Figure 3] 3(A) to 3(D) are circuit diagrams illustrating the circuit used in the measurement method S30 and the state of the circuit during each measurement. [Figure 4] FIG. 4(A) is a circuit diagram illustrating a circuit used in the measurement method S30 and the state of the circuit during measurement (e). FIG. 4(B) is a flowchart illustrating a path resistance measurement method S30 according to another embodiment. FIG. 4(C) is a flowchart illustrating a battery charge / discharge inspection method S100 according to one embodiment. FIG. 4(D) is a flowchart illustrating a battery charging method S200 according to one embodiment. FIG. 4(E) is a flowchart illustrating a battery manufacturing method S300 according to one embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the present invention is not limited to these embodiments. The drawings do not necessarily reflect accurate dimensions. In addition, some symbols may be omitted in the drawings. In this specification, unless otherwise specified, the expression "A to B" for numerical values ​​A and B means "greater than or equal to A and less than or equal to B." In such an expression, when a unit is assigned only to numerical value B, the unit is also applied to numerical value A. Furthermore, the words "or" and "or" mean a logical sum unless otherwise specified. Furthermore, the expression "E1 and / or E2" for elements E1 and E2 means "E1 or E2, or a combination thereof," and the expression "E1 and / or E2" means "E1 or E2, or a combination thereof," and the expression "E1, ..., E" means "E1 and / or E2, or a combination thereof." N (N is an integer greater than or equal to 3) for E1, ..., E N-1 , and / or E N " is written as "E1, ..., E N-1 , or E N or a combination thereof.”

[0013] <1. Path resistance measurement method (1)> FIG. 1A is a flowchart illustrating a path resistance measurement method S10 according to one embodiment of the present invention. The measurement method S10 is a method for measuring the path resistance of a circuit that conducts current to a battery B1. The battery B1 has a first electrode having a first polarity and a second electrode having a second polarity opposite to the first polarity. Here, the first electrode is a positive electrode (first polarity is +) and the second electrode is a negative electrode (second polarity is −), as an example. The measurement method S10 includes an acquisition step S1 and a calculation step S2. FIGS. 1B to 1D are circuit diagrams illustrating a circuit used in the measurement method S10 and the state of the circuit during each measurement. The circuit shown in FIGS. 1B to 1D includes a battery B1, a DC power supply VCC, a first path R1 connected to the positive electrode of the battery B1, a second path R2 connected to the negative electrode of the battery B1, and a third path R3 connected to the negative electrode of the battery B1. The first path R1 includes a switch SW1 inserted therein, and the other end of the first path R1 is connected to the positive terminal (terminal of a first polarity) of the DC power supply VCC. The third path R3 includes a switch SW3 inserted therein, and the other end of the third path R3 is connected to the negative terminal (terminal of a second polarity) of the DC power supply VCC. The second path R2 includes a four-circuit, three-contact switch SW2 inserted therein, and in the first position of the switch SW2, the other end of the second path R2 is connected to the negative terminal of the DC power supply VCC. In the second position, the other end of the second path R2 is open. In the third position, the other end of the second path R2 is connected to the positive terminal of the DC power supply VCC. The first path R1 has a first resistance value r1, the second path R2 has a second resistance value r2, and the third path R3 has a third resistance value r3. It is preferable that the resistance value of the second path R2 when the switch SW2 is in the first position is as close as possible to the resistance value when the switch SW2 is in the third position, and the difference between the two may be, for example, 0 to 5%, or 0 to 3%, or 0 to 1% of the average value of the two.

[0014] In the acquisition step S1, the following three measurements (a) to (c) are performed. Referring to FIG. 1B, in measurement (a), a first current value I is measured in a first circuit in which a first path R1, a battery B1, and a second path R2 are connected in series in this order. 12 By applying current through the battery B1, the voltage VB1 (= open circuit voltage + battery overvoltage) and the voltage drop r1I that occurred in the first path R1 12 and the voltage drop r2I that occurs in the second path R2 12 a first total voltage value V 12 Measurement (a) can be performed by closing switch SW1, opening switch SW3, and placing switch SW2 in the first position.

[0015] Referring to FIG. 1(C), in measurement (b), a second current value I 13 By applying current through the battery B1, the voltage VB1 (= open circuit voltage + battery overvoltage) and the voltage drop r1I that occurred in the first path R1 13 and the voltage drop r3I that occurs in the third path R3 13 and a second total voltage value V 13 Measurement (b) can be performed by closing both switches SW1 and SW3 and placing switch SW2 in the second position.

[0016] Referring to FIG. 1(D), in measurement (c), a third current value I 23 By applying current through the second path R2, the voltage drop r2I 23 and the voltage drop r3I that occurs in the third path 23 and a third total voltage value V 23 Measurement (c) can be taken with switch SW1 open, switch SW3 closed, and switch SW2 in its third position.

[0017] In the calculation step S2, the first to third current values ​​I 12 , I13 , and I 23 , and the first to third total voltage values ​​V 12 , V 13 , and V 23 The first to third total voltage values ​​V are calculated based on the second resistance value r2 and / or the third resistance value r3. 12 , V 13 , and V 23 are the open circuit voltage OCV1 and battery overvoltage Vov1 of the battery B1, the first to third resistance values ​​r1, r2, and r3, and the first to third current values ​​I 12 , I 13 , and I 23 Using this, it is expressed as follows: V 12 =OCV1+V ov1 +r1I 12 +r2I 12 …(1) V 13 =OCV1+V ov1 +r1I 13 +r3I 13 …(2) V 23 =r2I 23 +r3I 23 …(3) From (1) + (3) - (2), the open circuit voltage and battery overvoltage are eliminated. V 12 +V 23 -V 13 =r1(I 12 -I 13 )+r2(I 12 +I 23 )+r3(I 23 -I 13 ) It becomes. |I 12 -I 13 | / |I 12 +I 23 |<<1 and |I 23 -I 13 | / |I 12 +I 23 |<<1, i.e., I 12 ≒I 13 ≒I 23 When ≒ I, r2=(V 12 +V 23-V 13 ) / (2I) Similarly, from (2) + (3) - (1), V 13 +V 23 -V 12 =r1(I 13 -I 12 )+r2(I 23 -I 12 )+r3(I 13 +I 23 ) From |I 13 -I 12 | / |I 13 +I 23 |<<1 and |I 23 -I 12 | / |I 13 +I 23 |<<1, i.e., I 12 ≒I 13 ≒I 23 When ≒ I, r3=(V 13 +V 23 -V 12 ) / (2I) In order to improve the accuracy of the calculated resistance value, the first to third current values ​​I 12 , I 13 , and I 23 Regarding the ratio |I 12 -I 13 | / |I 12 +I 23 |, |I 23 -I 13 | / |I 12 +I 23 |, |I 13 -I 12 | / |I 13 +I 23 | and |I 23 -I 12 | / |I 13 +I 23 The value of | may preferably be 0 to 0.05, or 0 to 0.03, or 0 to 0.01, respectively.

[0018] <2. Path resistance measurement method (2)> FIG. 2(A) is a flowchart illustrating a path resistance measurement method S20 according to another embodiment of the present invention. The measurement method S20 is a method for measuring the path resistance of a circuit that passes current through two batteries B1 and B2. Each of the batteries B1 and B2 has a first electrode having a first polarity and a second electrode having a second polarity opposite to the first polarity. Here, an example will be described in which the first electrode is a positive electrode (first polarity is +) and the second electrode is a negative electrode (second polarity is −). The measurement method S20 includes an acquisition step S21 and a calculation step S22. FIGS. 2(B) to 2(D) are circuit diagrams illustrating a circuit used in the measurement method S20 and the state of the circuit during each measurement. 2B-2D includes a first battery B1, a second battery B2, a DC power supply VCC, a first path R1 connected to the positive electrode of the first battery B1, a second path R2 connected to the negative electrode of the first battery B1 and the positive electrode of the second battery B2, and a third path R3 connected to the negative electrode of the second battery B2. The first path R1 includes a switch SW1 inserted therethrough, and the other end of the first path R1 is connected to the positive terminal (first polarity terminal) of the DC power supply VCC. The third path R3 includes a switch SW3 inserted therethrough, and the other end of the third path R3 is connected to the negative terminal (second polarity terminal) of the DC power supply VCC. The second path R2 includes a four-circuit, three-contact switch SW2 inserted therein. When the switch SW2 is in its first position, the other end of the second path R2 is connected to the negative terminal of the DC power supply VCC. When the switch SW2 is in its second position, the other end of the second path R2 is open. When the switch SW2 is in its third position, the other end of the second path R2 is connected to the positive terminal of the DC power supply VCC. The first path R1 has a first resistance value r1, the second path R2 has a second resistance value r2, and the third path R3 has a third resistance value r3. It is preferable that the resistance value of the second path R2 when the switch SW2 is in the first position is as close as possible to the resistance value when the switch SW2 is in the third position. The difference between the two values ​​may be, for example, 0 to 5%, 0 to 3%, or 0 to 1% of the average of the two values.

[0019] In the acquisition step S21, the following three measurements (a) to (c) are performed. Referring to FIG. 2B, in measurement (a), a first current value I is measured in a first circuit in which a first path R1, a battery B1, and a second path R2 are connected in series in this order. 12 By applying current through the battery B1, the voltage VB1 (= open circuit voltage + battery overvoltage) and the voltage drop r1I that occurred in the first path R1 12 and the voltage drop r2I that occurs in the second path R2 12 a first total voltage value V 12 Measurement (a) can be performed by closing switch SW1, opening switch SW3, and placing switch SW2 in the first position.

[0020] Referring to FIG. 2(C), in measurement (b), a second current value I 13 By applying current through the battery B1, the voltage VB1 (= open circuit voltage + battery overvoltage), the voltage VB2 (= open circuit voltage + battery overvoltage), and the voltage drop r1I that occurred in the first path R1 13 and the voltage drop r3I that occurs in the third path R3 13 and a second total voltage value V 13 Measurement (b) can be performed by closing both switches SW1 and SW3 and placing switch SW2 in the second position.

[0021] Referring to FIG. 2(D), in measurement (c), a third current value I 23 By applying current through the battery B2, the voltage VB2 (= open circuit voltage + battery overvoltage) and the voltage drop r2I that occurred in the second path R2 23 and the voltage drop r3I that occurs in the third path 23 and a third total voltage value V 23The total voltage value Vt3 in measurement (c) can be obtained by opening the switch SW1, closing the switch SW3, and setting the switch SW2 to the third position.

[0022] The calculation step S22 calculates the first to third current values ​​I 12 , I 13 , and I 23 , and the first to third total voltage values ​​V 12 , V 13 , and V 23 This is a step of calculating the second resistance value r2 based on the first to third total voltage values ​​V 12 , V 13 , and V 23 is the open circuit voltage OCV1 of battery B1 and the battery overvoltage V ov1 , the open circuit voltage OCV2 of battery B2 and the battery overvoltage V ov2 , first to third resistance values ​​r1, r2, and r3, and first to third current values ​​I 12 , I 13 , and I 23 Using this, it is expressed as follows: V 12 =OCV1+V ov1 +r1I 12 +r2I 12 …(4) V 13 =OCV1+V ov1 +OCV2+V ov2 +r1I 13 +r3I 13 …(5) V 23 =OCV2+V ov2 +r2I 23 +r3I 23 …(6) From (4) + (6) - (5), the open circuit voltage and battery overvoltage are eliminated. V 12 +V 23 -V 13 =r1(I 12 -I 13 )+r2(I 12 +I 23 )+r3(I 23 -I 13 ) It becomes. |I12 -I 13 | / |I 12 +I 23 |<<1 and |I 23 -I 13 | / |I 12 +I 23 |<<1, i.e., I 12 ≒I 13 ≒I 23 When ≒ I, r2=(V 12 +V 23 -V 13 ) / (2I) In order to improve the accuracy of the calculated resistance value, the first to third current values ​​I 12 , I 13 , and I 23 Regarding the ratio |I 12 -I 13 | / |I 12 +I 23 | and |I 23 -I 13 | / |I 12 +I 23 The value of | may preferably be 0 to 0.05, or 0 to 0.03, or 0 to 0.01, respectively.

[0023] <3. Path resistance measurement method (3)> FIG. 4(B) is a flowchart illustrating a path resistance measurement method S30 according to another embodiment of the present invention. The measurement method S30 is a method for measuring the path resistance of a circuit that conducts current to batteries B1, ..., B8. Each of batteries B1, ..., B8 has a first electrode having a first polarity and a second electrode having a second polarity opposite to the first polarity. Here, an example will be described in which the first electrode is a negative electrode (first polarity is -) and the second electrode is a positive electrode (second polarity is +). The measurement method S30 includes an acquisition step S31 and a calculation step S32. FIGS. 3(A) to 3(D) and 4(A) are circuit diagrams illustrating the circuit used in the measurement method S30 and the state of the circuit during each measurement. The circuit shown in Figures 3(A) to 3(D) and 4(A) includes batteries B1, ..., B8, DC power supplies VCC0, VCC1, ..., VCC4, paths R- and R0 connected to the negative terminal of battery B1, path Rn (n is an integer between 1 and 7) connected to the positive terminal of battery Bn and the negative terminal of battery Bn+1, and paths R8 and R+ connected to the positive terminal of battery B8. Path R- includes a switch SW- inserted midway, and the other end of path R- is connected to the negative terminal (terminal of first polarity) of DC power supply VCC0. Path R0 includes a four-circuit, three-contact switch SW0 inserted midway, and in a first position of switch SW0, the other end of path R0 is connected to the positive terminal (terminal of second polarity) of DC power supply VCC0. In a second position, the other end of path R0 is open. In a third position, the other end of path R0 is connected to the negative terminal of DC power supply VCC0. Path R2n-1 (n is an integer between 1 and 4) includes a four-circuit, three-contact switch SW2n-1 inserted in the middle thereof, and in the first position of switch SW2n-1, the other end of path R2n-1 is connected to the negative electrode of DC power supply VCCn, in the second position, the other end of path R2n-1 is open, and in the third position, the other end of path R2n-1 is connected to the positive electrode of DC power supply VCCn-1.Path R2n (n is an integer between 1 and 4) includes a 5-circuit 4-contact switch SW2n inserted therein, and in the first position of switch SW2n, the other end of path R2n is connected to the positive electrode of DC power supply VCCn, in the second position the other end of path R2n is open, in the third position the other end of path R2n is connected to the negative electrode of DC power supply VCCn, and in the fourth position the other end of path R2n is connected to the positive electrode of DC power supply VCCn-1. The other end of path R+ is connected to the positive electrode of DC power supply VCC4. Paths R- and R+ each have a resistance value r. - and r + The path Rn (n is an integer from 0 to 8) has a resistance value r n In each of the paths R2n-1 (n is an integer from 1 to 4), it is preferable that the resistance value when the switch SW2n-1 is in the first position is as close as possible to the resistance value when the switch SW2n-1 is in the third position, and the difference between the two values ​​may be, for example, 0 to 5%, 0 to 3%, or 0 to 1% of the average value of the two values. In each of the paths R2n (n is an integer from 1 to 4), it is preferable that the resistance value when the switch SW2n is in the first position is as close as possible to the resistance value when the switch SW2n is in the third position, and the resistance value when the switch SW2n is in the fourth position is as close as possible to the resistance value when the switch SW2n is in the first position, and the resistance value when the switch SW2n is in the third position, and the resistance value when the switch SW2n is in the fourth position are as close as possible to the resistance value when the switch SW2n is in the first position, and the resistance value when the switch SW2n is in the fourth position, and the maximum difference between the two values ​​may be, for example, 0 to 5%, 0 to 3%, or 0 to 1% of the average value.

[0024] In the acquisition step S31, the following measurements (a) to (d) are performed, and in one embodiment, the following measurement (e) can also be performed. Referring to FIG. 3A, in measurement (a), a current value I is supplied from a DC power supply VCC0 to a circuit in which a path R0 and a path R- are connected in series in this order. 0,- By applying current through the path R0, the voltage drop r0I 0,- and the voltage drop r that occurs on path R- - I 0,- The total voltage value V 0,- Furthermore, a current value I is supplied from the DC power supply VCCn to a circuit in which the path R2n-1, the battery B2n, and the path R2n are connected in series in this order. 2n-1,2nBy applying current through the path R2n-1, the voltage drop r 2n-1 I 2n-1,2n and the voltage VB of battery B2n 2n (= open circuit voltage + battery overvoltage) and the voltage drop r that occurs in path R2n 2n I 2n-1,2n The total voltage value V 2n-1,2n (n is an integer between 1 and 4) V 0,- =r0I 0,- +r - I 0,- …(7) V 2n-1,2n =VB 2n +r 2n-1 I 2n-1,2n +r 2n I 2n-1,2n (n is an integer between 1 and 4) ...(8) Measurement (a) can be performed by closing switch SW-, opening switch SW+, and setting switches SWn (n is an integer from 0 to 8) to their first positions.

[0025] Referring to FIG. 3B, in measurement (b), a current value I 8,+ By applying current through the 8,+ and the voltage drop r that occurs on path R+ + I 8,+ The total voltage value V 8,+ Furthermore, a current value I is supplied from the DC power supply VCCn to a circuit in which the path R2n, the battery B2n+1, and the path R2n+1 are connected in series in this order. 2n,2n+1 By applying current through the path R2n, the voltage drop r 2n I 2n,2n+1 and the voltage VB of battery B2n+1 2n+1 (= open circuit voltage + battery overvoltage) and the voltage drop r that occurs on path R2n+1 2n+1 I 2n,2n+1 The total voltage value V 2n,2n+1 (n is an integer between 0 and 3) V 8,+ =r8I 8,+ +r+ I 8,+ …(9) V 2n,2n+1 =VB 2n+1 +r 2n I 2n,2n+1 +r 2n+1 I 2n,2n+1 (n is an integer between 0 and 3) ...(10) Measurement (b) can be performed by opening switch SW-, closing switch SW+, and setting switch SWn (n is an integer from 0 to 8) to the third position.

[0026] Referring to FIG. 3(C), in measurement (c), a current value I 1,- By applying current through the 1,- The voltage VB1 of battery B1 (= open circuit voltage + battery overvoltage) and the voltage drop r that occurred on path R- - I 1,- The total voltage value V 1,- Furthermore, a current value I is supplied from the DC power supply VCCn to a circuit in which the path R3n-1, the battery B3n, the battery B3n+1, and the path R3n+1 are connected in series in this order. 3n-1,3n+1 By applying current through the path R3n-1, the voltage drop r 3n-1 I 3n-1,3n+1 and the voltage VB of battery B3n 3n and the voltage VB of battery B3n+1 3n+1 and the voltage drop r that occurs on path R3n+1 3n+1 I 3n-1,3n+1 The total voltage value V 3n-1,3n+1 (n is an integer between 1 and 2) V 1,- =VB1+r1I 1,- +r - I 1,- …(11) V 3n-1,3n+1 =VB 3n +VB 3n+1 +r 3n-1 I 3n-1,3n+1 +r 3n+1 I 3n-1,3n+1 (n is an integer between 1 and 2) ...(12) Measurement (c) can be performed by closing switch SW-, opening switch SW+, setting switch SW3n (n is an integer between 0 and 2) to the second position, switches SW6n+1 and 6n+2 (n is an integer between 0 and 1) to the third position, switch SW6n+4 (n=0) to the fourth position, and switch SW6n+5 (n=0) to the first position.

[0027] Referring to FIG. 3(D), in measurement (d), a current value I 3n,3n+2 By applying current through the 3n I 3n,3n+2 and the voltage VB of battery B3n+1 3n+1 and the voltage VB of battery B3n+2 3n+2 and the voltage drop r that occurs on path R3n+2 3n+2 I 3n,3n+2 The total voltage value V 3n,3n+2 (n is an integer between 0 and 2) V 3n,3n+2 =VB 3n+1 +VB 3n+2 +r 3n I 3n,3n+2 +r 3n+2 I 3n,3n+2 (n is an integer between 0 and 2) ...(13) Measurement (d) can be performed by opening switches SW- and SW+, setting switch SW3n+1 (n is an integer from 0 to 2) to the second position, switch SW6n (n is an integer from 0 to 1) to the third position, switch SW6n+2 (n is an integer from 0 to 1) to the fourth position, switch SW6n+3 (n=0) to the first position, and switch SW6n+5 (n=0) to the third position.

[0028] In one embodiment, measurement (e) can be further performed. Referring to Fig. 4(A), in measurement (e), a current value I is supplied from a DC power supply VCC4 to a circuit in which a path R+, a battery B8, and a path R7 are connected in series in this order. 7,+By applying current through the + I 7,+ , the voltage VB8 of the battery B8, and the voltage drop r7I that occurred in the path R7. 7,+ The total voltage value V 7,+ That is, V 7,+ =VB8+r + I 7,+ +r7I 7,+ …(14) The total voltage value in measurement (e) is V 7,+ The current value I is acquired by closing the switch SW+, setting the switch SW7 to the first position, and setting the switch SW8 to the second position. In one embodiment, a current value I is acquired by connecting the path R3n-2, the battery B3n-1, the battery B3n, and the path R3n in series in this order. 3n-2,3n By applying current through the path R3n-2, the voltage drop r 3n-2 I 3n-2,3n and the voltage VB of battery B3n-1 3n-1 and the voltage VB of battery B3n 3n and the voltage drop r that occurs on path R3n 3n I 3n-2,3n The total voltage value V 3n-2,3n (n is an integer between 1 and 2) can be further obtained. V 3n-2,3n =VB 3n-1 +VB 3n +r 3n-2 I 3n-2,3n +r 3n I 3n-2,3n (n is an integer between 1 and 2) ...(15) The total voltage value in measurement (e) is V 3n-2,3n (n is an integer between 1 and 2) can be obtained by opening switch SW-, setting switch SW3n-1 (n is an integer between 1 and 2) to the second position, setting switch SW6n+1 (n is an integer between 0 and 1) to the first position, setting switch SW6n+3 (n=0) to the third position, setting switch SW6n+4 (n=0) to the third position, and setting switch SW6n (n=1) to the fourth position.

[0029] The calculation step S32 calculates the resistance values ​​r0 and / or r1 based on the total voltage value acquired in each measurement in the acquisition step S31 and the current value used in each measurement in the acquisition step S31. - , resistance value r8 and / or r + and resistance values ​​R1 to R7. Each resistance value can be determined by solving the simultaneous equations of the above formulas (7) to (13), and in one embodiment, formula (14) and / or formula (15), by eliminating the battery voltages VB1 to VB8 in a manner similar to the measurement methods S10 and S20 described above.

[0030] In order to improve the accuracy of the calculated resistance value, two current values ​​I selected from a set consisting of the current values ​​of measurements (a) to (d) and, if the result of measurement (e) is used, the current value of the measurement result used in measurement (e) j , I k For any pair of |I j -I k | / |I j +I k is preferably 0 to 0.05, or 0 to 0.03, or 0 to 0.01.

[0031] When a battery is energized, if the voltage is measured using the same path as the current path, the voltage drop caused by the parasitic resistance of the current path is added to the battery voltage, making it impossible to accurately measure the battery voltage during current flow. In contrast, the path resistance measurement method of the present invention allows current to flow through multiple paths for a short period of time before charging, thereby measuring the path resistance, including terminal resistance. This allows current to be applied during charging while taking into account the voltage drop caused by parasitic resistance, making it possible to control the charging state so that the battery's specified voltage is not exceeded. Furthermore, even when measuring the voltage using the same path as the current path, it is possible to detect abnormalities in the charging path, such as poor contact.

[0032] Although the above description of the present invention has mainly focused on the measurement method S30 for measuring the path resistance of a circuit in which an even number of batteries are connected, the present invention is not limited to this. For example, the measurement method may be configured to measure the path resistance of a circuit in which an odd number of batteries are connected.

[0033] <4. Battery charge / discharge inspection method> FIG. 4(C) is a flowchart illustrating a battery charge / discharge inspection method S100 according to one embodiment of the present invention. The inspection method S100 includes a resistance measurement step S101 and an inspection step S102. The resistance measurement step S101 is a step of measuring the path resistance of a circuit that conducts current to the battery using the path resistance measurement method S10, S20, or S30 described above. The inspection step S102 is a step of inspecting the charging and / or discharging of the battery using the circuit used in the resistance measurement step S101 based on the path resistance value measured in the resistance measurement step S101. For example, an abnormality in the charging path or discharging path can be detected based on the resistance measurement results. An example of an abnormality in the charging path or discharging path is a poor contact.

[0034] <5. How to charge the battery> FIG. 4(D) is a flowchart illustrating a battery charging method S200 according to one embodiment of the present invention. The charging method S200 includes a resistance measurement step S201 and a charging step S202. The resistance measurement step S201 is a step of measuring the path resistance of a circuit that conducts current to the battery using the path resistance measurement method S10, S20, or S30 described above. The charging step S202 is a step of charging the battery using the circuit used in the resistance measurement step S201 based on the path resistance value measured in the resistance measurement step S201. When charging a battery, a voltage drop due to parasitic resistance in the current path is added to the battery voltage. However, in the charging method S200, the path resistance is accurately determined in the resistance measurement step S201. Therefore, by taking into account the voltage drop due to parasitic resistance in the current path, it is possible to accurately determine the battery voltage during charging, and to control the charging state so that the battery voltage does not exceed the specified voltage, for example. Furthermore, for example, if measurement method S20 or S30 is used in resistance measurement step S201, it is possible to charge multiple batteries at once.

[0035] 6. Battery manufacturing method FIG. 4(E) is a flowchart illustrating a battery manufacturing method S300 according to one embodiment of the present invention. The manufacturing method S300 includes an assembly step S301 and a charging step S302. The assembly step S301 is a step of assembling a secondary battery. The type of secondary battery is not particularly limited, and secondary battery assembly can be performed using a known method. The charging step S302 is a step of charging the battery using the battery charging method S200 described above. If necessary, an initial charging step may be performed after the assembly step S301 and before the charging step S302, in which the battery is charged to a certain level. In the initial charging step, multiple batteries may be connected in series and charged together. For example, if multiple batteries are connected in series and charged simultaneously, variations in the charge rate may occur due to variations in the capacity of each battery. In the charging step S302, the batteries are charged until they reach a specified state of charge. Because charging can be performed while taking into account the parasitic resistance of the current path, it is possible to accurately determine the battery voltage during current flow and control the charging state so that it does not exceed the specified voltage of the battery, for example. According to the battery manufacturing method of the present invention, when manufacturing a plurality of batteries, it is possible to make the state of charge of each manufactured battery uniform with higher accuracy. [Example]

[0036] The present invention will be described in more detail below with reference to examples.

[0037] Example 1 Three measurements (a), (b), and (c) were performed using the path resistance measurement method S20 (see FIG. 2) of the present invention. The path resistance (first resistance value r1) of the first path R1 was adjusted to 1.0 Ω using a known resistor, and the path resistance (third resistance value r3) of the third path R3 was adjusted to 2.0 Ω using a known resistor. In measurements (a), (b), and (c), the first current I 12 = second current I 13 = third current I 23 When current is applied at I = 0.5 A, the first total voltage value V 12 =3.8672V, the second total voltage value V 13 =8.1166V, the third total voltage value V 23=4.3728V. By solving the simultaneous equations (4), (5), and (6), the second resistance value is r2 = (V 12 +V 23 -V 13 ) / (2I)=0.1244Ω. [Explanation of symbols]

[0038] B1, B2: Battery, R1, R2, R3, R4: Current path, SW1, SW2, SW3, SW4: Switch, VCC: DC power supply

Claims

1. A method for measuring a path resistance of a circuit that energizes a battery, comprising: the battery comprises a first electrode having a first polarity and a second electrode having a second polarity opposite to the first polarity; The method comprises: (i) Using a first path connected to a first electrode of the battery and having a first resistance value, a second path connected to a second electrode of the battery and having a second resistance value, and a third path connected to the second electrode of the battery and having a third resistance value, the following (a) to (c): (a) A first current value I is supplied to a first circuit in which the first path, the battery, and the second path are connected in series in this order. １２ By applying current through the first path, a first total voltage value V is obtained, which includes the voltage of the battery, the voltage drop occurring in the first path, and the voltage drop occurring in the second path. １２ To obtain (b) A second current value I is supplied to a second circuit in which the first path, the battery, and the third path are connected in series in this order. １３ By applying current through the first path, a second total voltage value V is obtained, which includes the voltage of the battery, the voltage drop occurring in the first path, and the voltage drop occurring in the third path. １３ and (c) a third current value I is supplied to a third circuit in which the second path and the third path are electrically connected in series; ２３ By applying current through the second path, a third total voltage value V ２３ To obtain and (ii) the first current value I １２ , the second current value I １３ , and the third current value I ２３ , and the first total voltage value V １２ , the second total voltage value V １３ , and the third total voltage value V ２３ calculating the second resistance value and / or the third resistance value based on the A path resistance measurement method comprising:

2. 1. A method for measuring a path resistance of a circuit energizing a first battery and a second battery, comprising: the first battery and the second battery each include a first electrode having a first polarity and a second electrode having a second polarity opposite to the first polarity; The method comprises: (i) Using a first path connected to a first electrode of the first battery and having a first resistance value, a second path connected to a second electrode of the first battery and a first electrode of the second battery and having a second resistance value, and a third path connected to a second electrode of the second battery and having a third resistance value, the following (a) to (c): (a) A first current value I is supplied to a first circuit in which the first path, the first battery, and the second path are connected in series in this order. １２ By applying current through the first path, a first total voltage value V is generated, which includes the voltage of the first battery, the voltage drop occurring in the first path, and the voltage drop occurring in the second path. １２ To obtain (b) A second current value I is supplied to a second circuit in which the first path, the first battery, the second battery, and the third path are connected in series in this order. １３ By applying current through the first path, a second total voltage value V is generated, which includes the voltage of the first battery, the voltage of the second battery, the voltage drop occurring in the first path, and the voltage drop occurring in the third path. １３ and (c) a third current value I is supplied to a third circuit in which the second path, the second battery, and the third path are electrically connected in series; ２３ By applying current through the second path, a third total voltage value V is generated, which includes the voltage of the second battery, the voltage drop occurring in the second path, and the voltage drop occurring in the third path. ２３ To obtain and (ii) the first current value I １２ , the second current value I １３ , and the third current value I ２３ , and the first total voltage value V １２ , the second total voltage value V １３ , and the third total voltage value V ２３ calculating the second resistance value based on the A path resistance measurement method comprising:

3. (i) measuring the path resistance of a circuit that energizes a battery by the method of claim 1 or 2; (ii) checking the charging and / or discharging of the battery using the circuit based on the value of the path resistance measured in step (i); A battery charge / discharge inspection method, comprising:

4. (i) measuring the path resistance of a circuit for charging a battery by the method of claim 1 or 2; (ii) charging the battery using the circuit based on the value of the path resistance measured in step (i); a method for charging the battery, including

5. Assembling a battery; Charging the battery according to the method of claim 4; A method for manufacturing a battery, comprising:

Images