Battery inspection device

Abstract

To simply measure the amount of battery expansion.SOLUTION: A battery inspection device includes one or more movable inspection electrodes that correspond to the position of the side of a secondary battery to be inspected, and one or more electrode patterns that extend along the direction of expansion of the secondary battery and contact the inspection electrodes. An inspection circuit outputs an inspection voltage corresponding to the contact point between the inspection electrode and the electrode pattern. The expansion estimation unit estimates the amount of expansion of the secondary battery according to the inspection voltage.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a battery inspection device for measuring changes in the shape of an object such as a battery. [Background technology]

[0002] During the development of secondary batteries, charge-discharge tests are conducted on the multiple cells that make up the secondary battery. In these tests, various charge-discharge conditions, such as external temperature and charge voltage, are set to evaluate the performance of the cells, including their internal resistance and discharge voltage.

[0003] As the temperature rises during charging, gas is generated from the electrolyte contained in the secondary battery cell, and the internal pressure of this gas causes the cell to expand. Since excessive cell expansion is dangerous, it is necessary to measure the amount of cell expansion during charging and discharging and determine the cell's usage conditions. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] U.S. Patent No. 1,153,9086 [Patent Document 2] Japanese Patent Application Laid-Open No. 2016-126943 [Patent Document 3] International Publication No. 2023 / 219040 Summary of the Invention [Problem to be solved by the invention]

[0005] Various methods have been proposed for measuring the amount of cell expansion, including a capacitance measurement method (Patent Document 1), an acoustic resonance sensor measurement method (Patent Document 1), a pressure sensor measurement method (Patent Document 1), and a light measurement method using light such as a light-emitting diode or laser (Patent Document 2).

[0006] Although some conventional measurement methods offer high measurement accuracy and resolution, they generally require high measurement costs. Currently, there are few proposals for a method to measure cell expansion inexpensively and reliably, while allowing for some error.

[0007] The present invention was completed based on the above-mentioned recognition of the problem by the inventor, and its main object is to provide a battery inspection device for easily measuring the amount of expansion of a battery. [Means for solving the problem]

[0008] In one embodiment of the present invention, a battery inspection device comprises one or more inspection electrodes that can move according to the position of a specific surface of the battery to be inspected, one or more electrode patterns that extend along the direction in which the battery expands and come into contact with the inspection electrodes, an inspection circuit that outputs an inspection voltage according to the contact point between the inspection electrode and the electrode pattern, and an expansion estimation unit that estimates the amount of expansion of the battery according to the inspection voltage. [Effects of the Invention]

[0009] According to the present invention, the amount of battery expansion can be easily measured. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 2 is a hardware configuration diagram of the battery inspection device. [Figure 2] 10A and 10B are schematic diagrams for explaining a method for measuring the amount of expansion of a secondary battery. [Figure 3] FIG. [Figure 4] FIG. [Figure 5] FIG. 10 is a front view of the inspection unit when the secondary battery expands. [Figure 6] FIG. 2 is a schematic diagram showing the relationship between the eight vertices of a secondary battery and the test electrodes. [Figure 7] FIG. 2 is a schematic diagram showing the relationship between an inspection electrode and an electrode pattern. [Figure 8] FIG. 1 is a circuit diagram of a test circuit (FLT). [Figure 9] FIG. 1 is a circuit diagram of a test circuit (FLB). [Figure 10] FIG. 10 is a data structure diagram of an expansion conversion table (L). [Figure 11] FIG. 10 is a data structure diagram of an expansion conversion table (R). [Figure 12] 10 is a flowchart showing the process of a charging test. [Figure 13] FIG. 1 is a diagram showing the data structure of test data. DETAILED DESCRIPTION OF THE INVENTION

[0011] The following description will be given assuming a charge / discharge test of a secondary battery under development. A secondary battery is usually configured as an assembly of units called a cell. In the following, the cell itself will be referred to as the secondary battery, not the assembly of cells. In this embodiment, the description will be given assuming a secondary battery (cell) with a rectangular parallelepiped shape with a thickness of about 30 millimeters and a longest side of about 40 centimeters.

[0012] As the internal temperature rises due to charging, the secondary battery gradually expands. Excessive expansion of the secondary battery is dangerous, so it is necessary to investigate in advance how the secondary battery will expand depending on the external temperature, charging voltage, and charging time. The battery inspection device 100 in this embodiment measures the amount of expansion of the secondary battery.

[0013] FIG. 1 is a diagram showing the hardware configuration of a battery inspection device 100. As shown in FIG. The battery testing device 100 includes a testing unit 102, a charge / discharge control unit 104, and a test recording unit 106. The inspection unit 102 measures the amount of expansion of the secondary battery 110. The charge / discharge control unit 104 controls charging and discharging of the secondary battery 110. The conditions under which the charge / discharge control unit 104 charges the secondary battery 110 are called "charging conditions." Possible charging conditions include charging voltage, charging time, external temperature, and internal temperature.

[0014] The inspection unit 102 includes a secondary battery 110 (cell), an inspection circuit 108 and an expansion estimation unit 112. The test circuit 108 outputs a test voltage (described later) in accordance with the expansion of the secondary battery 110. The expansion estimation unit 112 estimates the amount of expansion of the secondary battery 110 based on the test voltage. The test recording unit 106 records the charging conditions and the expansion amount in a file in association with each other.

[0015] The external configuration of the battery testing device 100 (particularly the testing unit 102) will be described below with reference to Figures 2 to 5. Details of the mechanism for outputting a test voltage in response to the expansion of the secondary battery 110 and the method for estimating the amount of expansion from the test voltage will be described with reference to Figures 7 and onwards.

[0016] FIG. 2 is a schematic diagram for explaining a method for measuring the amount of expansion of the secondary battery 110. In FIG. In the following description, as shown in FIG. 2, the X axis is set in the horizontal direction of the secondary battery 110, the Y axis is set in the depth direction, and the Z axis is set in the height direction. Two inspection plates 120a and 120b (hereinafter referred to as "inspection plates 120" when not otherwise distinguished) are installed on both side surfaces (YZ surfaces) of the secondary battery 110. The inspection plate 120 is actually configured as a combination of an upper plate and a lower plate, and details will be described later. For convenience of illustration, a gap is shown between the inspection plate 120 and the secondary battery 110 in FIG. 2, but in reality, the inspection plate 120 and the side surfaces of the secondary battery 110 are in contact. As the secondary battery 110 expands in the X direction, the inspection plate 120a slides in the positive direction of the X axis, and the inspection plate 120b slides in the negative direction of the X axis.

[0017] Eight electrode patterns 122 are arranged in the X direction. A total of eight test electrodes are arranged on two test plates 120, and each of the eight test electrodes is in contact with one of the eight electrode patterns 122. When the secondary battery 110 expands, the test plate 120 moves in the X direction, changing the contact points between the test electrodes attached to the test plate 120 and the electrode patterns 122. The test circuit 108 changes the test voltage according to the contact points between the test electrodes and the electrode patterns 122. The expansion estimation unit 112 estimates the amount of expansion of the secondary battery 110 based on the test voltage.

[0018] Fig. 3 is a front view of the inspection unit 102. Fig. 4 is a side view of the inspection unit 102. The inspection unit 102 has a horizontal bottom plate 126 and a vertical outer frame plate 128. A battery fixing stand 124 is fixed on top of the bottom plate 126. The secondary battery 110 to be measured is fixed to the battery fixing stand 124. As described above, inspection plate 120a (for the right side) and inspection plate 120b (for the left side) are installed on both sides of the secondary battery 110 so as to be movable in the X direction.

[0019] Inspection plate 120a includes two plates, an upper plate 132a and a lower plate 134a, which are connected by a housing member 136a (sheath). Inspection plate 120b also includes an upper plate 132b and a lower plate 134b, which are connected by a housing member 136b.

[0020] The enclosure member 136 (enclosure member 136a and enclosure member 136b) loosely connects the upper plate 132 (upper plate 132a and upper plate 132b) and the lower plate 134 (lower plate 134a and lower plate 134b) with some play. This configuration allows the upper plate 132 and the lower plate 134 to move independently to a certain extent. For example, when the upper portion of the right side of the secondary battery 110 expands significantly and the lower portion does not, the upper plate 132a moves relatively significantly and the lower plate 134a moves relatively less. By forming the inspection plate 120 from two plates and loosely connecting them with the enclosure member 136, the inspection plate 120 can move more easily in response to the expanding shape of the secondary battery 110 than if the inspection plate 120 were made of a single plate.

[0021] The two outer frame plates 128 are connected by rail members 140a to 140d extending in the X-axis direction. As shown in FIG. 4, two through holes 150 are formed above the top plate 132 (top plate 132a and top plate 132b), and rail members 140b and 140d pass through the through holes 150 of the top plate 132. Rail member 140b also passes through an annular member 152 that is adhered to the top plate 132a and top plate 132b. The annular member 152 can move along rail member 140b. The same is true for rail member 140d. With this configuration, the two top plates 132 can slide in the X direction along the rail members 140 (rail member 140b and rail member 140d).

[0022] An elastic member such as a spring 142 is installed between the annular member 152 and the outer frame plate 128, and the spring 142 urges the top plate 132a in a direction pressing it against the secondary battery 110. The urging force of the spring 142 keeps the top plate 132a in constant contact with the side of the secondary battery 110. The same is true for the top plate 132b.

[0023] Two through holes 150 are also formed below the bottom plate 134 (bottom plate 134a and bottom plate 134b). Rail members 140a and 140c pass through the through holes 150 in the bottom plate 134. Rail members 140a and 140c pass through an annular member 152 that is adhered to the two bottom plates 134. The bottom plate 134 moves in the X-axis direction along the rail members 140a and 140c. The bottom plate 134 is also biased toward the secondary battery 110 by a spring 142. The spring 142 keeps the bottom plate 134 in contact with the side of the secondary battery 110 at all times.

[0024] As described above, the secondary battery 110 is sandwiched between the inspection plate 120a (upper plate 132a and lower plate 134a) and the inspection plate 120b (upper plate 132b and lower plate 134b) and fixed to the battery fixing base 124. When the secondary battery 110 expands, the inspection plate 120a slides in the positive direction of the X axis, and the inspection plate 120b slides in the negative direction of the X axis.

[0025] Heat dissipation holes (not shown) may be formed in the upper plate 132, the lower plate 134, and the enclosure member 136. By forming the heat dissipation holes, heat generated from the secondary battery 110 can be more easily dissipated efficiently.

[0026] Four more electrode support plates 130a to 130d are connected between the two outer frame plates 128. An electrode pattern 122 is provided on each electrode support plate 130. A total of eight inspection electrodes 144 are provided on the upper surface plate 132 and the lower surface plate 134, and the inspection electrodes 144 are in contact with the electrode patterns 122.

[0027] FIG. 5 is a front view of the inspection unit 102 when the secondary battery 110 is expanded. When the secondary battery 110 expands, the right-side test plate 120a moves in the positive direction of the X-axis, and the left-side test plate 120b moves in the negative direction of the X-axis. As the test plate 120a moves, the four test electrodes 144 installed corresponding to the test plate 120a also move in the positive direction of the X-axis. The contact points between the test electrodes 144 and the electrode patterns 122 change, and the test circuit 108 changes the test voltage in accordance with these contact points, as described below.

[0028] As the inspection plate 120b moves, the four inspection electrodes 144 installed corresponding to the inspection plate 120b move in the negative direction of the X-axis. Eight types of inspection voltages are output from a total of eight inspection electrodes 144, and the amount of expansion of the secondary battery 110 is estimated from the combination of the eight types of inspection voltages.

[0029] FIG. 6 is a schematic diagram showing the relationship between the eight vertices of the secondary battery 110 and the test electrodes 144. As shown in FIG. The eight test electrodes 144 correspond to the eight vertices of the secondary battery 110. Hereinafter, the test electrode 144 corresponding to the front upper left vertex S (FLT: Front-Left-Top) of the secondary battery 110 will be referred to as "test electrode 144 (FLT)" and so on. The other seven test electrodes are the front lower left test electrode 144 (FLB: Front-Left-Bottom), the front upper right test electrode 144 (FRT: Front-Right-Top), the front lower right test electrode 144 (FRB: Front-Right-Bottom), the rear upper left test electrode 144 (BLT: Back-Left-Top), the rear lower left test electrode 144 (BLB: Back-Left-Bottom), the rear upper right test electrode 144 (BRT: Back-Right-Top), and the rear lower right test electrode 144 (BRB: Back-Right-Bottom).

[0030] Hereinafter, the eight electrode patterns 122 corresponding to the eight test electrodes 144(FLT) to 144(BRB), respectively, will be expressed as electrode pattern 122(FLT) to electrode pattern 122(BRB). The eight types of test voltages detected from the eight test electrodes 144(FLT) to 144(BRB), respectively, will be expressed as test voltage (FLT) to test voltage (BRB).

[0031] FIG. 7 is a schematic diagram showing the relationship between the inspection electrode 144 and the electrode pattern 122. As shown in FIG. A total of four test electrodes 144 are attached to test plate 120a (upper plate 132a and lower plate 134a), two on the top and two on the bottom. A total of four test electrodes 144 are also attached to test plate 120b (upper plate 132b and lower plate 134b). In Fig. 7, the four test electrodes 144 (FLT), test electrode 144 (FRT), test electrode 144 (FLB), and test electrode 144 (FRB) on the front side of secondary battery 110 and their corresponding electrode patterns 122 (FLT), electrode pattern 122 (FRT), electrode pattern 122 (FLB), and electrode pattern 122 (FRB) will be described, but the same concept applies to the test electrodes 144 and electrode patterns 122 on the rear side.

[0032] Conductive portions 154 and insulating portions 156 (hereinafter collectively referred to simply as "electrodes") are arranged alternately in the electrode pattern 122. The conductive portions 154 are formed from a conductive material such as copper, and the insulating portions 156 are formed from an insulating material such as resin. Details will be explained in relation to the following FIG. 8, but when the inspection electrode 144 is in contact with the conductive portion 154, an inspection voltage corresponding to the position of the conductive portion 154 is output. When the inspection electrode 144 is in contact only with the insulating portion 156, the inspection voltage is 0 (V).

[0033] In this embodiment, the width (length in the X direction) of both the conductive portion 154 and the insulating portion 156 is 2.0 mm. The width of the test electrode 144 is 1.2 mm. In the electrode pattern 122(FLT), the electrodes are arranged in the order of insulating portion 156(1), conductive portion 154(2), insulating portion 156(3), conductive portion 154(4), etc., from the center of the secondary battery 110 toward the negative direction of the X axis. In the electrode pattern 122(FLB), the electrodes are arranged in the order of conductive portion 154(1), insulating portion 156(2), conductive portion 154(3), insulating portion 156(4), etc., from the center of the secondary battery 110 toward the negative direction of the X axis.

[0034] When the secondary battery 110 is not expanded, the inspection electrode 144(FLT) contacts both the insulating portion 156(7) and the conductive portion 154(8), and the inspection electrode 144(FLB) contacts both the conductive portion 154(7) and the insulating portion 156(8). The inspection electrode 144(FLT) outputs an inspection voltage (FLT) corresponding to the conductive portion 154(8), and the inspection electrode 144(FLB) outputs an inspection voltage (FLB) corresponding to the conductive portion 154(7). The same applies to the other inspection electrodes 144, and the expansion estimation unit 112 estimates the width W1 of the secondary battery 110 when it is not expanded from the eight inspection voltages (described in more detail below).

[0035] In this embodiment, the width W1 of the secondary battery 110 in an unexpanded state is 28 (millimeters). The gap between two adjacent electrode patterns 122 in the X-axis direction is 2.0 (millimeters). For example, there is a gap of 2.0 (millimeters) between the electrode pattern 122 (FLT) and the electrode pattern 122 (FRT).

[0036] 7, the test electrode 144(FLT) contacts the conductive portion 154(10), and the test electrode 144(FLB) contacts the insulating portion 156(10). At this time, the test electrode 144(FLT) outputs a test voltage (FLT) corresponding to the conductive portion 154(10), and the test electrode 144(FLB) outputs a test voltage (FLB)=0 corresponding to the insulating portion 156(10). The expansion estimation unit 112 estimates the width W2 (>W1) of the secondary battery 110 when expanded from the eight test voltages.

[0037] As described above, the upper plate 132 and the lower plate 134 can move independently to some extent. Therefore, the X coordinates of the test electrode 144(FLT) and the test electrode 144(FLB) do not necessarily match. For example, when the upper part of the secondary battery 110 expands more than the lower part, the upper plate 132 moves more than the lower plate 134.

[0038] As shown in FIG. 7, the electrode pattern 122(FLT) and the electrode pattern 122(FLB) are arranged so that the conductive portion 154 and the insulating portion 156 are offset from each other so that when one is in the conductive portion 154 at the same X coordinate, the other is in the insulating portion 156.

[0039] For example, when the test electrode 144(FLT) is in contact with the conductive portion 154(10), the test electrode 144(FLB) may be in contact with the conductive portion 154(9) located further inward. From the combination of the test voltage (FLT) and the test voltage (FLB), it is possible to determine not only the amount of expansion of the secondary battery 110 but also the "expansion shape" to some extent.

[0040] FIG. 8 is a circuit diagram of the test circuit 108 (FLT). Eight test circuits 108 are provided for eight sets of test electrodes 144 and electrode patterns 122. FIG. 8 shows a test circuit 108 (FLT) for measuring expansion in the upper left front portion. The electrode pattern 122 (FLT) has 22 electrodes arranged from an insulating portion 156 (1) to a conductive portion 154 (22). Of these, eleven conductive portions 154 are connected to respective conductors. In the figure, an input voltage VCC is applied between connection points P0 and P1. The voltage between connection points P0 and P1 is divided by resistors R1 to R10. The resistors R1 to R10 have the same resistance. In this embodiment, connection point P0 is at ground potential.

[0041] When the test electrode 144 (FLT) is in contact with the conductive portion 154 (10), the test electrode 144 (FLT) corresponds to a position where the input voltage VCC is divided into four-tenths, so the potential of the test electrode 144 (FLT) is VCC × 4 / 10. The potential of the test electrode 144 (FLT) is input to the non-inverting input terminal (+) of the operational amplifier 170 (FLT), and the ground potential, which is the potential of the connection point P0, is input to the inverting input terminal (-). The differential amplification value of the operational amplifier 170 (FLT) becomes the test voltage (FLT). On the other hand, when the test electrode 144 is in contact with the insulating portion 156, the ground potential, which is the potential of the connection point P0, is input directly to the non-inverting input terminal of the operational amplifier 170, so the test voltage value, which is its output, becomes 0 (V). Hereinafter, the operational amplifier 170 (FLT) will be described as outputting n (V) as the test voltage (FLT) when the input voltage to the non-inverting input terminal (+) is VCC×n / 10 (n is an integer between 0 and 10).

[0042] FIG. 9 is a circuit diagram of the test circuit 108 (FLB). The inspection circuit 108 (FLB) has the same basic configuration as the inspection circuit 108 (FLT). The electrode pattern 122 (FLB) has 22 electrodes arranged from the conductive portion 154 (1) to the insulating portion 156 (22). Lead wires are connected to each of the 11 conductive portions 154.

[0043] When the test electrode 144 (FLB) is in contact with the insulating portion 156 (10), the potential of the test electrode 144 (FLB) is zero, and therefore the test voltage (FLB) is zero.

[0044] As described above, the width of conductive portion 154 and insulating portion 156 is 2.0 mm, and the width of test electrode 144 is shorter, at 1.2 mm. Therefore, test electrode 144 does not come into contact with multiple conductive portions 154 at the same time. When test electrode 144 comes into contact with both conductive portion 154 and insulating portion 156, a test voltage corresponding to conductive portion 154 is output. Test voltages are output in a similar manner from the remaining six test circuits 108. The expansion estimation unit 112 calculates the amount of expansion of the secondary battery 110 based on the eight types of test voltages using the method described below.

[0045] FIG. 10 is a diagram showing the data structure of the expansion conversion table 160(L). The expansion conversion table 160(L) is a data table for calculating the amount of expansion of the left side of the secondary battery 110, i.e., the left side of the secondary battery 110, from the test voltage (FLT) and the test voltage (FLB), and the test voltage (BLT) and the test voltage (BLB). In the battery testing device 100, a left expansion conversion table 160(L) and a right expansion conversion table 160(R) (described later) are prepared in advance.

[0046] For example, when the test voltage (FLT) is 4 (V), it is found that the test electrode 144 (FLT) is in contact with the conductive portion 154 (10) (see FIG. 8). In this case, the test electrode 144 is either (a) in contact with only the conductive portion 154 (10), (b) in contact with both the insulating portion 156 (9) and the conductive portion 154 (10), or (c) in contact with both the conductive portion 154 (10) and the insulating portion 156 (11).

[0047] On the other hand, suppose the test voltage (FLB) is 0 (V). In this case, it can be estimated that the test electrode 144 (FLT) is in contact only with the insulating portion 156 (10) (see FIG. 9). In the expansion conversion table 160 (L), combinations of the upper test voltage V (T) and the lower test voltage V (B) correspond to the movement distance of the test plate 120b. The expansion estimation unit 112 identifies the position (movement amount) of the test plate 120b from the combination of the upper test potential (FLT) and the lower test potential (FLB).

[0048] According to the expansion conversion table 160(L), the distance corresponding to the combination of test voltage (FLT) = 4(V) and test voltage (FLB) = 0(V) is "18.6 to 19.3 (mm)." The expansion estimation unit 112 identifies 18.95 (mm), which is the average value of "18.6 to 19.3 (mm)," as the left front position of the secondary battery 110.

[0049] The same applies to the test voltage at the left rear. Assume that the test voltage (BLT) at the upper left rear is 4 (V) and the test voltage (BLB) at the lower left rear is 5 (V). The expansion estimation unit 112 refers to the expansion conversion table 160(L) and identifies 19.95 (mm), which is the average value of the corresponding distance "19.4 to 20.5 (mm)", as the left rear position of the secondary battery 110. In this example, the left rear of the secondary battery 110 is more swollen than the left front.

[0050] FIG. 11 is a diagram showing the data structure of the expansion conversion table 160(R). The expansion conversion table 160(R) is a data table for calculating the amount of expansion of the right side of the secondary battery 110 from the test voltages of the test electrodes 144(FRT) and 144(FRB), and the test electrodes 144(BRT) and 144(BRB).

[0051] For example, suppose the test voltage (FRT) is 4 (V) and the test voltage (FRB) is 5 (V). The expansion estimation unit 112 refers to the expansion conversion table 160(L) and identifies the right front position of the secondary battery 110 as 19.95 (mm). If the test voltage (BRT) is 0 (V) and the test voltage (BRB) is 5 (V), the expansion estimation unit 112 identifies the right rear position of the secondary battery 110 as 20.95 (mm), which is the average value of "20.6 to 21.3 (mm)". In this example, the right rear of the secondary battery 110 is more swollen than the right front.

[0052] To sum up, (1) Left front position: 18.95 (mm) (2) Left rear position: 19.95 (mm) (3) Right front position: 19.95 (mm) (4) Right rear position: 20.95 (mm) This becomes:

[0053] The expansion estimation unit 112 identifies the average position in the left direction as 19.45 (millimeters) (= (18.95 + 19.95) / 2) as the position of the inspection plate 120b. Similarly, the expansion estimation unit 112 determines the average position in the right direction as 20.45 (millimeters) (= (19.95) + 20.95 / 2). Because there is a gap of 2.0 millimeters between adjacent electrode patterns 122 in the X direction, the expansion estimation unit 112 calculates the width W2 of the expanded secondary battery 110 as 19.45 + 2.0 + 20.45 = 41.9 (millimeters). Because the width W1 in the unexpanded state is 28 (millimeters), the expansion estimation unit 112 estimates the amount of expansion of the secondary battery 110 as 13.9 (millimeters) (= 41.9 - 28).

[0054] FIG. 12 is a flowchart showing the process of the charging test. When conducting a charging test, the user (tester) sets a limit value T for the amount of expansion in advance. The charge / discharge control unit 104 of the battery inspection device 100 automatically stops the charging test when the amount of expansion of the secondary battery 110 to be tested exceeds the limit value T. The user first sets charging conditions in the charge / discharge control unit 104 (S10). The charge / discharge control unit 104 starts charging the secondary battery 110 in accordance with the charging conditions.

[0055] The test recording unit 106 periodically measures the internal temperature of the secondary battery 110 using a temperature measuring device (not shown) that is preset in the secondary battery 110 (S12). The expansion estimation unit 112 calculates the amount of expansion of the secondary battery 110 after measuring the temperature using the method described above (S14). The expansion estimation unit 112 calculates the expansion rate (=(W2-W1) / W1) from the amount of expansion. The test recording unit 106 records the expansion rate together with the charging time and temperature in the test data 190 (see FIG. 13).

[0056] If the expansion amount is less than the limit value T (N in S18), the process returns to S12, and thereafter, the temperature measurement, the expansion rate measurement, and the recording in the test data 190 are repeated. If the expansion amount is equal to or greater than the limit value T (Y in S18), the charge / discharge control unit 104 stops charging (S20). The expansion amount is measured simultaneously with charging, and charging is automatically stopped when the expansion amount reaches the limit value T, so that the charge test can be performed safely. Similar processing can be applied to other tests such as discharge tests and temperature tests.

[0057] FIG. 13 is a diagram showing the data structure of the test data 190. The test recording unit 106 records the temperature and expansion rate measured periodically during the charging test in the test data 190. After the charging test is completed, the user can refer to the test data 190 to quantitatively know how much the secondary battery 110 expands depending on the temperature and charging time of the secondary battery 110 being tested.

[0058] [summary] The battery inspection device 100 has been described above based on the embodiment. In addition to charge / discharge tests, there are also situations where it is desirable to intentionally increase the internal pressure of the secondary battery 110 to simply measure the amount of expansion in order to check the heat resistance of the secondary battery 110. The battery inspection device 100 of this embodiment can measure the amount of expansion of the secondary battery 110 using a combination of relatively simple and inexpensive components, such as the inspection plate 120, electrode pattern 122, and inspection circuit 108. In the electrode pattern 122 of this embodiment, the width of the conductive portion 154 and insulating portion 156 is 2.0 millimeters. Therefore, the amount of expansion of the secondary battery 110 can be measured with a resolution of 2.0 millimeters. Reducing the width of the conductive portions 154, etc. enables higher-resolution measurements. On the other hand, reducing the number of conductive portions 154, etc., reduces measurement resolution but reduces the cost of the entire device.

[0059] The battery inspection device 100 contains almost no precision parts, making it less prone to breakdowns and easier to withstand harsh test conditions such as high temperature and humidity. Furthermore, if the battery inspection device 100 is provided with multiple inspection units 102, multiple secondary batteries 110 (cells) can be simultaneously tested at low cost.

[0060] The test voltage can be output as a digital value by arranging the conductive portions 154 and insulating portions 156 alternately in the electrode pattern 122. The method estimates the amount of expansion of the secondary battery 110 based on the combination of the test voltage and the expansion conversion table 160, so the algorithm can also be simplified.

[0061] The amount of expansion of the secondary battery 110 is measured at multiple points using eight test electrodes 144. The upper plate 132 and the lower plate 134 are loosely connected by the enclosure member 136 but can move independently, making it possible to measure distortion caused by expansion of the secondary battery 110 to a certain extent. In addition, the biasing force of the spring 142 keeps the test plate 120 in constant contact with the secondary battery 110, allowing the amount of expansion of the secondary battery 110 to be measured appropriately.

[0062] The battery inspection device 100 includes an inspection unit 102 that measures the amount of expansion, as well as a charge / discharge control unit 104 and a test recording unit 106. This allows the amount of expansion of the secondary battery 110 to be recorded while a charging test is being performed. While checking the amount of expansion of the secondary battery 110, the user can determine the specifications of a newly designed secondary battery 110, in other words, the conditions under which the secondary battery 110 can be used safely.

[0063] The present invention is not limited to the above-described embodiments and modifications, and the components can be modified without departing from the spirit of the invention. Various inventions can be formed by appropriately combining multiple components disclosed in the above-described embodiments and modifications. Furthermore, some components can be omitted from all the components shown in the above-described embodiments and modifications.

[0064] [Variations] In this embodiment, the spring 142 biases the annular member 152 to bring the inspection plate 120 and the secondary battery 110 into close contact with each other. However, this is not limiting, and an elastic body other than the spring 142 may be used to ensure close contact between the inspection plate 120 and the secondary battery 110. For example, a rubber piece may be connected between the inspection plates 120a and 120b, and the contraction force of the rubber may be used to firmly sandwich the secondary battery 110 between the inspection plates 120a and 120b.

[0065] The containment member 136 is not essential. The upper plate 132 and the lower plate 134 may be movable completely independently, or they may be connected by a spring, rubber, or string. The upper plate 132 may be configured as two plates, one for the front and one for the rear, which can move independently. The same applies to the lower plate 134.

[0066] In this embodiment, the expansion estimation unit 112 calculates the left front position of the secondary battery 110 based on a combination of the test voltage (FLT) and the test voltage (FLB). Similarly, the expansion estimation unit 112 calculates the left rear position of the secondary battery 110. The inspection unit 102 calculates the average value of the left front position and the left rear position as the left side position, and calculates the amount of expansion of the secondary battery 110 based on the left side position and the right side position. As a variant, the inspection unit 102 may determine either the left front position or the left rear position, for example, the larger, as the left side position. The same applies to the right side position.

[0067] One or more heat dissipation holes may be formed in the upper plate 132 and the lower plate 134. The number and shape of the heat dissipation holes may be arbitrary. The upper plate 132 and the lower plate 134 may be configured as a metal mesh, or a heat sink may be attached to the upper plate 132 and the lower plate 134. The heat sink may be equipped with fins for heat dissipation, or may be cooled by water or air.

[0068] In the present embodiment, a total of eight test electrodes 144 are installed on each side of one secondary battery 110, four on each side, to measure the amount of expansion of the secondary battery 110 at multiple points. As a modified example, only one side of the secondary battery 110 may be the measurement target. For example, the amount of expansion on the left side of the secondary battery 110 may be calculated from the test voltage (FLT), test voltage (FLB), test voltage (BLT), and test voltage (BLB), and twice this amount may be regarded as the amount of expansion of the secondary battery 110.

[0069] The number of test electrodes 144 may be nine or more, or seven or less. Only one test electrode 144 may be installed on the left side of the secondary battery 110, and the amount of expansion of the secondary battery 110 may be estimated from a single test voltage. Reducing the number of test electrodes 144 reduces the measurement resolution, but allows the battery test device 100 to have a simpler configuration. The number of test electrodes 144 and the number of conductive portions 154 and insulating portions 156 in the electrode pattern 122 may be adjusted as desired based on required specifications such as resolution and cost.

[0070] The amount of expansion may be measured simultaneously not only on one or two sides of the secondary battery 110 but also on three or more sides. For example, the inspection plate 120 may be installed on the XZ side of the secondary battery 110, and the amount of expansion in the Y direction may be measured in the same manner. The same applies to the Z direction.

[0071] In this embodiment, the secondary battery 110 is the object of measurement, but the object of measurement may also be a primary battery. The battery inspection device 100 may measure the amount of expansion of the primary battery while increasing the internal temperature of the primary battery.

[0072] The expansion measurement method described in this embodiment can be widely applied to products other than batteries, such as plastic containers and metal products, which may expand with temperature changes. [Explanation of symbols]

[0073] 100 Battery inspection device, 102 Inspection unit, 104 Charge / discharge control unit, 106 Test recording unit, 108 Inspection circuit, 110 Secondary battery, 112 Expansion estimation unit, 120 Inspection plate, 122 Electrode pattern, 124 Battery fixing base, 126 Bottom plate, 128 Outer frame plate, 130 Electrode support plate, 132 Top plate, 134 Bottom plate, 136 Enclosure member, 140 Rail member, 142 Spring, 144 Inspection electrode, 150 Through hole, 152 Annular member, 154 Conductive portion, 156 Insulating portion, 160 Expansion conversion table, 170 Operational amplifier, 190 Test data

Claims

1. one or more movable inspection electrodes that correspond to positions on a predetermined surface of the battery to be inspected; one or more electrode patterns extending along the expansion direction of the battery and contacting the test electrode; an inspection circuit that outputs an inspection voltage according to a contact point between the inspection electrode and the electrode pattern; an expansion estimation unit that estimates the amount of expansion of the battery according to the inspection voltage.

2. In the electrode pattern, conductive portions and insulating portions are arranged alternately, 2. The battery inspection device according to claim 1, wherein the inspection circuit outputs, as the inspection voltage, a divided voltage corresponding to a conductive portion that is in contact with the inspection electrode among a plurality of conductive portions arranged in the electrode pattern.

3. 3. The battery inspection device according to claim 2, wherein a length of the inspection electrode in the moving direction is shorter than a length of the insulating portion in the same direction.

4. 2. The battery testing device according to claim 1, further comprising one or more elastic members that urge the one or more testing electrodes in the direction of contraction of the battery.

5. the one or more inspection electrodes include a first inspection electrode provided corresponding to a first surface of the battery and a second inspection electrode provided corresponding to a second surface opposite to the first surface; the one or more electrode patterns include a first electrode pattern in contact with the first test electrode and a second electrode pattern in contact with the second test electrode; the test circuit detects first and second test voltages from the first test electrode and the second test electrode, respectively; The battery inspection device of claim 1, wherein the expansion estimation unit estimates a first expansion amount on the first surface of the battery from a first inspection voltage corresponding to the first inspection electrode, estimates a second expansion amount on the second surface of the battery from a second inspection voltage corresponding to the second inspection voltage, and estimates the expansion amount of the battery based on the first expansion amount and the second expansion amount.

6. the one or more test electrodes include a plurality of test electrodes provided corresponding to a first surface of the battery; the one or more electrode patterns include a plurality of electrode patterns in contact with the plurality of test electrodes, respectively; the inspection circuit detects an inspection voltage from each of the plurality of inspection electrodes; The battery inspection device according to claim 1 , wherein the expansion estimation unit estimates the amount of expansion of the first surface of the battery based on the plurality of inspection voltages.

7. further comprising an upper plate and a lower plate that are in contact with the first surface and are movable according to the position of the first surface; 7. The battery inspection device according to claim 6, wherein a plurality of inspection electrodes provided corresponding to the first surface are connected to either the upper surface plate or the lower surface plate.

8. 8. The battery inspection device according to claim 7, wherein heat dissipation holes are provided in both or one of the upper and lower plates.

9. The battery is a secondary battery, a charge / discharge control unit that controls charging and discharging of the secondary battery; 2. The battery inspection device according to claim 1, further comprising a test recording unit that records both or either of a set value and a measured value during charging and discharging in association with the estimated amount of expansion.

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