JP6743758B2 - Battery manufacturing method - Google Patents

Description

The present invention relates to a battery manufacturing method including a battery performance test for determining the quality of a battery by measuring an IV resistance value at a predetermined battery voltage.

For batteries such as lithium-ion secondary batteries, various battery performance tests are performed before shipment. For example, during the initial charging process, the battery under test is initially charged with a predetermined charging current value Id to a predetermined test voltage Va, and then the IV resistance value Rb of the battery under test is measured. A performance test is known in which the battery under test is determined to be non-defective if the following is true. For non-defective batteries, the initial charging process is further continued. As a related art related to this, for example, Patent Document 1 can be cited.

JP, 2016-162559, A

By the way, when performing the above-mentioned battery performance inspection, stack a plurality of test batteries, restrain both ends of the stacked test battery groups with restraint jigs, and perform the performance test of each test battery at the same time. Is possible. In this inspection, when each inspected battery is initially charged to the inspection voltage Va with the same charging current value Id as described above, the inspection voltage Va is reached due to the difference in the location where each inspected battery is placed. It has been found that the battery temperature Td(n) reached by each battery under test sometimes varies.

The reason why the battery temperature Td(n) varies in this way is considered as follows. That is, the battery to be inspected generates heat by charging and the battery temperature rises. However, each battery to be inspected in the restraint jig may be placed between the batteries or between the battery and the restraint jig depending on the place where the battery is placed. Have different heat transfer properties. Also, depending on the location of the battery to be inspected, the airflow for air temperature adjustment in the inspection space such as in the constant temperature chamber may differ. The environment may differ. In these cases, it is considered that the battery temperature Td(n) varies when the inspection voltage Va reaches the arrangement position of each inspected battery.

On the other hand, it has also been found that the IV resistance value Rb(n) varies depending on the battery temperature Td(n). Specifically, the IV resistance value Rb(n) tends to increase as the battery temperature Td(n) decreases, and the IV resistance value Rb(n) tends to decrease as the battery temperature Td(n) increases. Therefore, when determining the quality of the battery under test based on the value of the IV resistance value Rb(n), if the battery temperature Td(n) of the battery is different from the reference temperature, the measured IV resistance value Rb( It is difficult to make a determination by comparing n) with a predetermined threshold value.

The present invention has been made in view of the present situation, and the IV resistance value Rb(n) is set after charging a plurality of batteries to be inspected arranged at a predetermined arrangement location under a predetermined temperature environment. An object of the present invention is to provide a method for manufacturing a battery, which is capable of appropriately determining the quality of each inspected battery when measuring and determining the quality of each inspected battery based on the magnitude of the IV resistance value Rb(n). To do.

One mode of the present invention for solving the above-mentioned problem is a charging step of charging a plurality of batteries to be inspected, which are respectively arranged at predetermined arrangement locations, to the same inspection voltage Va under a predetermined temperature environment. Following the charging step, a resistance value measuring step of measuring the IV resistance values Rb(n) of the plurality of tested batteries, and the IV resistance value Rb(n) of the plurality of tested batteries being a threshold value. A determination step of determining the following inspected battery as a non-defective product, and arranging a plurality of evaluation batteries having the same configuration as the inspected battery at each of the arrangement locations, and under the temperature environment, the same evaluation charge When the battery is charged to the inspection voltage Va at the current value Ic, the plurality of batteries to be inspected are charged in the charging step based on the evaluation battery temperatures Tc(n) reached by the evaluation batteries when the inspection voltage Va is reached. The inspection charging current value Ia(n) of the charging current to be passed is as small as the inspected battery arranged in the location where the evaluation battery temperature Tc(n) is high, and all of the plurality of inspected batteries are In the case of a non-defective product, the variation of the inspected battery temperature Ta(n) reached by each of the inspected batteries when the inspection voltage Va reaches in the charging step is smaller than the variation of the evaluation battery temperature Tc(n). In the above, the charging step is a method of manufacturing a battery in which each of the plurality of batteries to be inspected is charged with the inspection charging current value Ia(n) determined for each location.

In the above-described battery manufacturing method, the test charging current value Ia(n) of each inspected battery in the charging step is not set to a uniform value, but charged at different current values for each location of the inspected battery. To do. Specifically, as described above, the inspection charging current value Ia(n) of each inspected battery has a smaller value for the inspected battery placed at the location where the evaluation battery temperature Tc(n) is higher, and The variation of the inspected battery temperature Ta(n) is set in advance to a value smaller than the variation of the evaluation battery temperature Tc(n). Then, in the charging step, each inspected battery is charged with the inspection charging current value Ia(n) determined for each location. As a result, the variation in the inspected battery temperature Ta(n) of each inspected battery at the end of the charging process can be made smaller than in the case where the inspection charging current value Ia(n) is a uniform value. Therefore, the IV resistance value Rb(n) of each inspected battery can be appropriately measured in the resistance value measuring step, and the quality of each inspected battery can be appropriately determined by the predetermined threshold value in the determination step.

The “placement location” of the plurality of batteries to be inspected is, for example, when the charging process is performed in a state in which the plurality of batteries to be inspected are constrained using a restraint jig, The locations of the batteries to be inspected are listed. Therefore, in this case, arranging the plurality of evaluation batteries at the locations where the inspection batteries are arranged means that the plurality of evaluation batteries are constrained by using the same constraining jig as that used for the inspection batteries. Point to.
In addition, when arranging each battery to be inspected in a room where the charging process is performed, such as in a thermostatic chamber, consider the effect of the air flow in the room, and place each battery to be inspected in the room. Is the above-mentioned "placement location". Therefore, in this case, arranging a plurality of evaluation batteries at the locations of the batteries to be inspected means to arrange the batteries for evaluation at the same locations in the room as the locations of the batteries to be inspected. Point to.
In addition, the “temperature environment” in which the charging process is performed includes, for example, how the airflow hits. Therefore, charging a plurality of evaluation batteries under the temperature environment of the battery to be inspected means charging the evaluation battery in a state in which the airflow strikes are the same.

The “inspection voltage Va” is the battery voltage at which the measurement of the IV resistance value Rb(n) is started. Specifically, it is preferable that the battery voltage corresponds to SOC within the range of SOC 5% to SOC 50%, and further that the battery voltage corresponds to SOC within the range of SOC 10% to SOC 30%.
The "evaluation charging current value Ic" and the "inspection charging current value Ia(n)" are preferably in the range of 0.5C to 10.0C, respectively, and further in the range of 1.0C to 7.0C. It is preferable to set the inside.

Furthermore, in the above-described battery manufacturing method, the plurality of batteries to be inspected and the plurality of batteries for evaluation are both constrained by a constraining jig of a predetermined form, and the arrangement location is determined. The production method is preferable.

When the charging process is performed with a plurality of batteries to be inspected restrained by the restraint jig, the heat conductivity of the batteries to be inspected differs depending on the location of each of the batteries to be inspected, as described above. Therefore, if the inspection charging current value Ia(n) of each inspected battery is set to a uniform value, the inspected battery temperature Ta(n) at the end of the charging process tends to greatly vary.
On the other hand, in the battery manufacturing method described above, as described above, each inspected battery is charged at the inspection charging current value Ia(n) determined for each location. For this reason, even though the charging process is performed while the plurality of batteries to be inspected are held by the restraining jig, the variation in the temperature Ta(n) of the batteries to be inspected at the end of the charging process becomes small. Therefore, the IV resistance value Rb(n) of each inspected battery can be appropriately measured, and the quality of each inspected battery can be appropriately determined.

It is a perspective view of the battery which concerns on embodiment. It is a longitudinal section of a battery concerning an embodiment. 4 is a flowchart of a method for manufacturing a battery according to an embodiment. FIG. 6 is an explanatory diagram showing a state in which a plurality of batteries are restrained by a restraint jig according to the embodiment. It is a graph which shows the relationship between the arrangement|positioning location of seven to-be-tested batteries, and the to-be-tested battery temperature Ta (n) at the time of reaching|attaining the test voltage Va. 7 is a graph showing the relationship between the locations of seven evaluation batteries and the evaluation battery temperature Tc(n) when the inspection voltage Va is reached. 5 is a graph showing a relationship between a charging current value I and a battery temperature T reached when the charging current value I is charged up to the inspection voltage Va. 7 is a graph showing the relationship between the battery temperature T when the inspection voltage Va is reached and the IV resistance value Rb measured at the battery temperature T.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 and 2 show a perspective view and a vertical sectional view of a battery 1 according to this embodiment. In the following description, the battery thickness direction BH, the battery horizontal direction CH, and the battery vertical direction DH of the battery 1 will be described as the directions shown in FIGS. 1 and 2.
The battery 1 is a square and sealed lithium-ion secondary battery that is mounted in a vehicle such as a hybrid car, a plug-in hybrid car, an electric vehicle, or the like. The battery 1 includes a battery case 10, an electrode body 20 housed inside the battery case 10, a positive electrode terminal member 50 and a negative electrode terminal member 60 supported by the battery case 10. Further, the electrolytic solution 17 is contained in the battery case 10, and a part of the electrolytic solution 17 is impregnated in the electrode body 20.

Of these, the battery case 10 has a rectangular parallelepiped box shape and is made of metal (aluminum in this embodiment). The battery case 10 is composed of a bottomed rectangular tubular case body member 11 having an opening only on the upper side, and a rectangular plate-like case lid member 13 welded to close the opening of the case body member 11. It A positive electrode terminal member 50 made of aluminum is fixed to the case lid member 13 in a state of being insulated from the case lid member 13. The positive electrode terminal member 50 is connected to the positive electrode plate 21 of the electrode body 20 in the battery case 10 so as to be conductive, while penetrating the case lid member 13 and extending to the outside of the battery. Further, a negative electrode terminal member 60 made of copper is fixed to the case lid member 13 while being insulated from the case lid member 13. The negative electrode terminal member 60 is connected to the negative electrode plate 31 of the electrode body 20 in the battery case 10 so as to be conductive, while penetrating the case lid member 13 and extending to the outside of the battery.

The electrode body 20 has a flat shape and is accommodated in the battery case 10 in a state of being laid sideways. A bag-shaped insulating film surrounding body 19 made of an insulating film is arranged between the electrode body 20 and the battery case 10. The electrode body 20 includes a strip-shaped positive electrode plate 21 and a strip-shaped negative electrode plate 31, which are stacked on each other via a pair of separators 41 and 41 made of a resin-made porous film and wound around an axis to be flattened. It is compressed. The positive electrode plate 21 has a positive electrode active material layer made of a positive electrode active material, a conductive material, and a binder provided in a belt shape at predetermined positions on both main surfaces of a positive electrode current collector foil made of a belt-shaped aluminum foil. Further, the negative electrode plate 31 is provided with a strip of a negative electrode active material layer composed of a negative electrode active material, a binder and a thickener at predetermined positions on both main surfaces of a negative electrode current collector foil made of a strip-shaped copper foil.

Next, a method for manufacturing the battery 1 will be described (see FIG. 3). First, in the "assembly step S1", the battery 1 is assembled. Hereinafter, the assembled battery 1 is also referred to as a battery 1 to be inspected. Specifically, the positive electrode plate 21 and the negative electrode plate 31 are wound on top of each other with a pair of separators 41, 41 interposed therebetween, and compressed into a flat shape to form the electrode body 20. Next, the case lid member 13 is prepared, and the positive electrode terminal member 50 and the negative electrode terminal member 60 are fixedly attached thereto (see FIGS. 1 and 2). Then, the positive electrode terminal member 50 and the negative electrode terminal member 60 are welded to the positive electrode plate 21 and the negative electrode plate 31 of the electrode body 20, respectively. Next, the electrode body 20 is covered with the insulating film surrounding body 19, these are inserted into the case body member 11, and the opening of the case body member 11 is closed with the case lid member 13. Then, the case body member 11 and the case lid member 13 are welded together to form the battery case 10. After that, the electrolytic solution 17 is injected into the battery case 10 through the injection hole 13h to impregnate the inside of the electrode body 20. Then, the sealing member 15 seals the liquid injection hole 13h.

Next, prior to performing the "first charging step S2", the battery 1 to be inspected is restrained by the restraint jig 200 of a predetermined form (see FIG. 4). Specifically, a plurality of (7 in this embodiment) tested batteries 1 and 3 dummy batteries 1x are prepared, and these tested batteries 1 and dummy batteries 1x are arranged in a row in the battery thickness direction BH. .. The dummy battery 1x described above does not function as a battery because it does not contain the electrolytic solution 17, and is otherwise the same as the battery 1 to be inspected.
It should be noted that in the following, the leftmost placement location NO. The battery 1 to be inspected arranged in No. 1 is the first battery 1A to be inspected, and the arrangement location NO. The battery 1 to be inspected arranged in No. 2 is the second battery 1B to be inspected, and the arrangement location NO. The inspected battery 1 arranged in No. 3 is called the third inspected battery 1C in order, and the arrangement location NO. The inspected battery 1 arranged in No. 7 is referred to as a seventh inspected battery 1G. In addition, the location NO. 8 is the first dummy battery 1xA, the dummy battery 1x arranged on the right side of the dummy battery 1x. 9 is the second dummy battery 1xB, and the dummy battery 1x located at the rightmost placement position NO. The dummy battery 1x arranged in No. 10 is referred to as a third dummy battery 1xC.

Then, the first inspection battery 1 (first inspection battery 1A to seventh inspection battery 1G) and the dummy battery 1x (first dummy battery 1xA to third dummy battery 1xC) that are stacked on both ends The side surface 10c having the largest area of the inspected battery 1A and the third dummy battery 1xC is sandwiched between the pair of plate-shaped end plates 210, 210 of the restraint jig 200 in the battery thickness direction BH, and the end plates 210, 210 are not separated from each other. The spaces are connected by a plurality of restraining rods 220. Thereby, the plurality of batteries 1 (1A to 1G) to be inspected and the plurality of dummy batteries 1x (1xA to 1xC) are constrained in a state of being pressed in the battery thickness direction BH. In the present embodiment, the plurality of batteries 1 to be inspected and the plurality of dummy batteries 1x are thus restrained by the restraint jig 200 in the “first charging step S2” to the “aging step S6” described below. Do in the state.

After that, the restraint jig 200, the plurality of batteries 1 (1A to 1G) to be inspected and the plurality of dummy batteries 1x (1xA to 1xC) restrained by the restraint jig 200 are arranged at predetermined positions in the room where the air conditioner is installed. To do. Further, in the present embodiment, the way in which the airflow from the air conditioner hits the inspected battery 1 and the dummy battery 1x is NO. 1-NO. 10, the temperature environment differs for each inspected battery 1 and each dummy battery 1x. Under this temperature environment, "first charging step S2" to "second charging step S5" are performed.

Next, in the "first charging step S2", the test battery 1 (1A to 1G) is initially charged. Specifically, a charging/discharging device is connected to each inspected battery 1, and all inspected batteries 1 are charged to the same inspection voltage Va (3.44 V corresponding to SOC 15% in this embodiment). It should be noted that, for each dummy battery 1x (1xA to 1xC), this initial charging and measurement of the IV resistance value Rb described later are not performed.
In the first charging step S2, the arrangement location NO. 1-NO. Each to-be-tested battery 1 is charged with a predetermined test charging current value Ia(n) for each 7. Specifically, as shown in Table 1, the test charging current value Ia(1) of the first tested battery 1A is 3.75C, and the test charging current value Ia(2) of the second tested battery 1B is 2. 50C, inspection charge current value Ia(3) of the third inspected battery 1C is 3.75C, inspection charge current value Ia(4) of fourth inspected battery 1D is 2.50C, inspection of the fifth inspected battery 1E The charging current value Ia(5) is 3.75C, the inspection charging current value Ia(6) of the sixth tested battery 1F is 3.75C, and the inspection charging current value Ia(7) of the seventh tested battery 1G is 3. 75C. The method of setting these inspection charging current values Ia(n) will be described later.

Further, the battery temperature Te(n) of each of all the batteries 1 to be inspected was measured immediately before starting the initial charging. As shown in Table 1, the battery temperature Te(n) of each of the batteries 1 (1A to 1G) to be inspected was 18.5°C immediately before the start of charging.

Further, the temperature Ta(n) of the inspected batteries at the end of the first charging step S2 (when the inspection voltage Va reached) was measured for each of the inspected batteries 1. As shown in Table 1 and FIG. 5, the inspected battery temperature Ta(1) of the first inspected battery 1A was 20.3° C. The inspected battery temperature Ta(2) and the inspected battery temperature Ta(4) of the second inspected battery 1B and the fourth inspected battery 1D were 21.0°C. The inspected battery temperature Ta(3) of the third inspected battery 1C was 20.2°C. The inspected battery temperature Ta(5) and the inspected battery temperature Ta(6) of the fifth inspected battery 1E and the sixth inspected battery 1F were 20.8°C. The inspected battery temperature Ta(7) of the seventh inspected battery 1G was 20.4°C. The variation σa of these inspected battery temperatures Ta(n) was 0.336. The magnitude of this variation σa will be described later.
Each value of the inspected battery temperature Ta(n) shown in Table 1 is the inspected battery temperature Ta(n) of the inspected battery 1 which is determined as a non-defective product in the determination step S4 described later.

Here, a method of setting the inspection charging current value Ia(n) of the charging current flowing through each inspected battery 1 in the first charging step S2 will be described. The inspection charging current value Ia(n) was determined as follows. That is, a plurality (seven in the present embodiment) of evaluation batteries 2 having the same configuration as the above-described inspected battery 1 and the above-described three dummy batteries 1x were prepared. The evaluation battery 2 and the dummy battery 1x are used by using the above-described restraint jig 200 used to restrain the tested batteries 1A to 1G and the dummy batteries 1xA to 1xC, and the tested batteries 1A to 1G and the dummy. Batteries 1xA to 1xC were restrained in the same manner as when restrained.

In addition, in FIG. 1 (the same position as the first battery 1A to be inspected), the evaluation battery 2 is the first evaluation battery 2A, and the arrangement location NO. The evaluation batteries 2 arranged in the second evaluation battery 2B (at the same position as the second inspected battery 1B) are referred to as the second evaluation battery 2B in order, and the arrangement location NO. The evaluation battery 2 arranged in 7 (at the same position as the seventh inspection battery 1G) is referred to as a seventh evaluation battery 2G.

Then, the first charging step S2 is performed on the test batteries 1 (1A to 1G) of the evaluation batteries 2 (2A to 2G) and the dummy batteries 1x (1xA to 1xC) which are restrained by the restraint jig 200. Arranged in the same room and in the same place. In addition, the setting of the air conditioner in this room is the same as the setting of the first charging step S2 for the battery 1 to be inspected.
Next, with respect to all the evaluation batteries 2, the battery temperature Tf(n) immediately before starting the initial charging was measured. The arrangement location and temperature environment of each of the evaluation batteries 2 in the room are the same as in the case of each of the batteries to be inspected 1 described above. Therefore, as shown in Table 1, the battery temperature Tf(n) of any of the evaluation batteries 2 (2A to 2G) immediately before the start of charging is the battery temperature Te(n) of each of the tested batteries 1 immediately before the start of charging. The same was 18.5°C.

After that, all the batteries 2 for evaluation were charged to the above-described inspection voltage Va (3.44 V in this embodiment) with the same evaluation charging current value Ic (5.00 C in this embodiment). Then, the evaluation battery temperature Tc(n) reached by each evaluation battery 2 when the inspection voltage Va reached was measured. As shown in Table 1 and FIG. 6, the evaluation battery temperature Tc(1) of the first evaluation battery 2A is 21.3° C., the evaluation battery temperature Tc(2) of the second evaluation battery 2B is 21.9° C., The evaluation battery temperature Tc(3) and the evaluation battery temperature Tc(7) of the third evaluation battery 2C and the seventh evaluation battery 2G are 21.0° C., and the evaluation battery temperature Tc(4) of the fourth evaluation battery 2D is The evaluation battery temperature Tc(5) of the second evaluation battery 2E was 22.3° C., and the evaluation battery temperature Tc(6) of the sixth evaluation battery 2F was 21.8° C. Further, the variation σc of these evaluation battery temperatures Tc(n) is 0.489.

The reason why the evaluation battery temperature Tc(n) greatly varies depending on the evaluation battery 2 is considered as follows. That is, although each evaluation battery 2 generates heat by charging and the battery temperature rises, each evaluation battery 2 in the restraint jig 200 has its location NO. 1-NO. 7 has different heat conductivity. Therefore, the location of the evaluation battery 2 in the restraint jig 200 is NO. 1-NO. 7, it is considered that the evaluation battery temperature Tc(n) varies greatly. Further, the location of the evaluation battery 2 is NO. 1-NO. Since the way the airflow from the air conditioner hits differs depending on the location No. 7, 1-NO. It is considered that the evaluation battery temperature Tc(n) largely varies due to No. 7.

Here, the relationship between the charging current value I when the evaluation battery 2 is initially charged and the battery temperature T reached when charging the inspection voltage Va with the charging current value I will be described (see FIG. 7 ). FIG. 7 shows the charging current value I and the inspection voltage Va when the evaluation battery 2 in a state where the battery temperature T is 22.5° C. immediately before the start of charging is initially charged to the above-described inspection voltage Va=3.44V. The relationship with the battery temperature T at the time of arrival is shown. As is clear from FIG. 7, the smaller the charging current value I, the lower the battery temperature T when the inspection voltage Va reaches. Therefore, the location NO. 1-NO. If the charging current value I is set to be smaller for the evaluation battery 2 in which the evaluation battery temperature Tc(n) becomes higher due to No. 7, the arrangement location NO. 1-NO. It is considered that variation in the evaluation battery temperature Tc(n) due to No. 7 can be suppressed.

Therefore, in the first charging step S2, the inspection charging current value Ia(n) of the charging current flowing through each inspected battery 1 is set to the location NO. 1-NO. The battery 1 to be inspected arranged in No. 7 is set to a smaller value. In the present embodiment, the arrangement location NO. 3 where the evaluation battery temperature Tc(n) was particularly high. 2, NO. 4, the inspection charging current values Ia(2) and Ia(4) in the first charging step S2 were set to a low value of 2.50C as shown in Table 1. On the other hand, the arrangement location NO. 1, NO. 3, NO. 5 to NO. For No. 7, the inspection charging current values Ia(1), Ia(3), Ia(5) to Ia(7) were set to 3.75C. Then, by setting the inspection charging current value Ia(n) in this way, the variation σa=0.336 (see also FIG. 5) of the inspected battery temperature Ta(n) becomes equal to the evaluation battery temperature Tc(n). The variation was smaller than σc=0.489 (see also FIG. 6).

After the completion of the first charging step S2, the "resistance value measuring step S3" is performed to measure the IV resistance value Rb(n) of each of the tested batteries 1 (1A to 1G). Specifically, the resistance value measuring step S3 is performed without waiting for the other test battery 1 to reach the test voltage Va from the test battery 1 whose battery voltage has reached the test voltage Va in the first charging step S2. I do. The inspected battery 1 whose battery voltage has reached the inspection voltage Va is discharged at a predetermined discharge current value Ih=5.00C=25.0A for 5.00 seconds, and t1 seconds (in the present embodiment, from the start of this discharge). The battery voltage V1(n) after t1=0.00 seconds) and the battery voltage V2(n) after t2 seconds (t2=4.00 seconds in this embodiment) are measured, respectively, and Rb(n) is measured. =(V1(n)-V2(n))/Ih was used to calculate the IV resistance value Rb(n) of each battery 1 to be inspected.

Next, in the "judgment step S4", the IV resistance value Rb(n) of the seven test batteries 1 (1A to 1G) is a predetermined threshold value Rs or less (Rb(n)≤Rs) The battery 1 is determined to be good. On the other hand, the inspected battery 1 whose IV resistance value Rb(n) exceeds the threshold value Rs is determined as a defective product, and after the "aging step S6" described later is completed and the restrained state of the inspected battery 1 is released, it is discarded.

Here, the relationship between the battery temperature T when the inspection voltage Va reaches and the IV resistance value Rb measured at the battery temperature T will be described (see FIG. 8 ). As is clear from FIG. 8, the IV resistance value Rb varies depending on the battery temperature T when the IV resistance is measured. Specifically, it can be seen that the lower the battery temperature T during the IV resistance measurement, the larger the IV resistance value Rb. Therefore, when the inspection battery temperature Ta(n) when the inspection voltage Va reaches (at the end of the first charging step S2) is significantly different from the reference temperature Ts (21.0° C. in the present embodiment), it was measured. It is difficult to properly determine the quality of each battery under test 1 based on the IV resistance value Rb(n) at a predetermined threshold value Rs. On the other hand, in the present embodiment, as described above, the inspection charging current value Ia(n) of each battery under test 1 in the first charging step S2 is set to the location NO. 1-NO. By setting every seven, the variation σa of the inspected battery temperature Ta(n) is reduced (σa=0.336), and the temperature difference from the reference temperature Ts is reduced. Therefore, based on the IV resistance value Rb(n), it is possible to appropriately determine the quality of each battery under test 1 with the predetermined threshold value Rs.

Next, in the "second charging step S5", recharging is performed in order from the battery 1 to be inspected, which has completed the determination step S4. Specifically, all the batteries 1 to be inspected are charged to 4.10V corresponding to SOC 100% by constant current constant voltage (CCCV) charging. Specifically, after charging at a constant current of 5.00C until the battery voltage reached 4.10V, this battery voltage=4.10V was maintained until the charging current value reached 0.25C. When the second charging step S5 is completed for all the inspected batteries 1, the next aging step S6 is performed.

Next, each inspected battery 1 (1A to 1G) and each dummy battery 1x constrained by the constraining jig 200 are moved to another room, and at a temperature of 40 to 85° C. in the “aging step S6”. Then, each inspected battery 1 is aged. Specifically, at a temperature of 63° C., each inspected battery 1 is left for 20 hours with its terminals open, and each inspected battery 1 is aged. After this aging step S6 is completed, the restraint jig 200 that restrains each inspected battery 1 and each dummy battery 1x is removed, and the restrained state of the inspected battery 1 and the dummy battery 1x is released. Further, the battery 1 to be inspected, which has been determined to be defective in the determination step S4, is discarded. Thus, the battery 1 is completed.

As described above, in the method for manufacturing the battery 1, the inspection charging current value Ia(n) of each inspected battery 1 (1A to 1G) in the first charging step S2 is not a uniform value, but Placement No. of the battery 1 to be inspected 1-NO. Charging is performed with a different current value for each 7. Specifically, as described above, the inspection charging current value Ia(n) of each inspected battery 1 is set to the location NO. 1 where the evaluation battery temperature Tc(n) is high. 1-NO. The battery 1 to be inspected arranged in No. 7 has a smaller value, and the variation σa of the battery temperature Ta(n) to be inspected is smaller than the variation σc of the evaluation battery temperature Tc(n).

Then, in the first charging step S2, the arrangement location NO. 1-NO. Each inspected battery 1 is charged with the inspection charging current value Ia(n) determined for each 7. Thereby, the variation σa of the inspected battery temperature Ta(n) of each inspected battery 1 at the end of the first charging step S2 can be made smaller than in the case where the inspection charging current value Ia(n) is set to a uniform value. Therefore, the IV resistance value Rb(n) of each battery under test 1 can be appropriately measured in the resistance value measuring step S3, and the quality of each battery under test 1 can be appropriately judged by the predetermined threshold value Rs in the judging step S4. ..

Further, in the present embodiment, since the first charging step S2 is performed in a state in which the plurality of batteries 1 to be inspected are restrained by the restraint jig 200, the arrangement location NO. 1-NO. The thermal conductivity of the inspected battery 1 varies depending on 7. Therefore, when the inspection charging current value Ia(n) of each inspected battery 1 is set to a uniform value, the inspected battery temperature Ta(n) at the end of the first charging step S2 tends to greatly vary. However, in the present embodiment, as described above, the location NO. 1-NO. Each inspected battery 1 is charged with the inspection charging current value Ia(n) determined for each 7. Therefore, even though the first charging step S2 is performed in a state in which the plurality of batteries 1 to be inspected are held by the restraint jig 200, the battery temperature Ta(n) to be inspected at the end of the first charging step S2 is The variation σa becomes small. Therefore, the IV resistance value Rb(n) of each inspected battery 1 can be appropriately measured, and the quality of each inspected battery 1 can be appropriately determined.

Although the present invention has been described above according to the embodiments, it goes without saying that the present invention is not limited to the above-described embodiments and can be appropriately modified and applied without departing from the scope of the invention.
For example, in the embodiment, the present invention relates to a plurality (7) of batteries 1 to be inspected when the plurality (7) of batteries 1 to be inspected and a plurality (3) of dummy batteries 1x are held by the holding jig 200. , But is not limited thereto. For example, the present invention can be applied to 10 inspected batteries 1 when 10 inspected batteries 1 are restrained by the restraint jig 200 described above without using the dummy battery 1x. Alternatively, the present invention is applied to seven inspected batteries 1 in the case where the seven inspected batteries 1 are restrained by a restraining jig different from the restraining jig 200 described above without using the dummy battery 1x. You can also The present invention can also be applied to the plurality of batteries 1 to be inspected even when the batteries 1 to be inspected are not constrained by a restraining jig such as placing a plurality of batteries 1 to be inspected at predetermined positions on a resin tray. it can.

1 battery (battery to be inspected)
2 Evaluation batteries 1A to 1G First inspected battery to seventh inspected battery 2A to 2G First evaluation battery to seventh evaluation battery 200 Restraining jig S1 Assembly step S2 First charging step S3 Resistance value measuring step S4 Judgment step NO. 1-NO. 10 Arrangement Place Ia(n) Inspection Charge Current Value Ic Evaluation Charge Current Value Va Inspection Voltage Te(n) Battery Temperature Tf(n) (Before Starting Charging of Battery Under Test) Battery (Before Starting Charging of Evaluation Battery) Battery Temperature Ta(n) Inspected battery temperature Tc(n) Evaluation battery temperature σa (Inspected battery temperature Ta(n)) variation σc (Evaluated battery temperature Tc(n)) variation Rb(n) IV resistance Rs threshold

Claims (1)

A charging step of charging a plurality of batteries to be inspected, which are respectively arranged at predetermined arrangement locations, to the same inspection voltage Va under a predetermined temperature environment;
Following the charging step, a resistance value measuring step of measuring the IV resistance values Rb(n) of the plurality of tested batteries, respectively.
A determination step of determining, as a non-defective battery, an inspected battery whose IV resistance value Rb(n) is equal to or less than a threshold value among the plurality of inspected batteries
When a plurality of batteries for evaluation having the same configuration as the battery to be inspected are respectively arranged at the above arrangement locations and are charged to the above inspection voltage Va at the same evaluation charging current value Ic under the above temperature environment, the above inspection voltage is obtained. Based on the evaluation battery temperatures Tc(n) that the evaluation batteries respectively reach when reaching Va,
The inspection charging current value Ia(n) of the charging current flowing through the plurality of batteries to be inspected in the charging step is
The battery to be inspected arranged at a location where the evaluation battery temperature Tc(n) is high has a smaller value, and
When all of the plurality of batteries to be inspected are non-defective, the variation in the battery temperature to be inspected Ta(n) reached by each of the batteries to be inspected when the inspection voltage Va reaches in the charging step is the evaluation battery temperature Tc. A value smaller than the variation of (n),
Have been set in advance,
The charging process is
A method of manufacturing a battery, wherein each of the plurality of batteries to be inspected is charged with the inspection charging current value Ia(n) determined for each location.

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