JP2018045874A - Battery manufacturing method - Google Patents

Abstract

The present invention can prevent or suppress ions contained in an electrolytic solution, which carry electric conductivity, from being diffused to a negative electrode active material layer which is located at the outermost side of an electrode body and does not contribute to a charge / discharge reaction of a battery. To provide a method for manufacturing a battery in which formation of a battery is easy. A method of manufacturing a battery includes a method in which a positive electrode plate and a negative electrode plate are alternately stacked with a separator interposed therebetween, and the uppermost negative electrode plate is separated from the upper side EA on the uppermost positive electrode plate with the separator interposed therebetween. The step S3 of forming the electrode body 20 so that the lowermost positive electrode plate 31B overlaps the lowermost positive electrode plate 21B from the lower EB via the separator 41 on the lowermost positive electrode plate 21B, the step S4 of assembling the battery 1, and the charged battery 1 And step S8 of detecting whether or not the battery 1 has an internal short circuit based on the amount of voltage drop ΔV of the battery voltage. [Selection diagram] FIG.

Description

  The present invention relates to a method of manufacturing a battery including a stacked electrode body in which a plurality of positive electrode plates and a plurality of negative electrode plates are alternately stacked via a separator, and an electrolyte solution impregnated in the electrode body.

  As a battery, a battery including an electrode body in which positive and negative electrode plates each having an active material layer formed on a current collector foil are stacked with a separator interposed therebetween is known. For example, Patent Document 1 discloses a battery including a wound electrode body in which a strip-shaped positive electrode plate and a strip-shaped negative electrode plate are alternately stacked with a pair of strip-shaped separators and wound flatly around an axis. Yes. Furthermore, in the wound electrode body of Patent Document 1, a portion of the negative electrode plate forming the outermost periphery of the electrode body is not provided with a negative electrode active material layer on the outer surface of the negative electrode current collector foil, that is, the outermost electrode body. There is no negative electrode active material layer on the outer periphery, and the negative electrode current collector foil is exposed (see FIG. 9 of Patent Document 1, claim 1, etc.). Thereby, ions responsible for electrical conduction such as lithium ions contained in the electrolyte solution are located on the outermost periphery of the electrode body and do not face the positive electrode active material layer via the separator (does not contribute to the charge / discharge reaction of the battery). Diffusion to the negative electrode active material layer can be prevented.

JP 2006-072012 A

  However, when manufacturing the electrode body as in Patent Document 1 (when the electrode body is formed by winding the positive electrode plate and the negative electrode plate a predetermined number of times through a separator), the electrode body may vary depending on the thickness variation of the positive electrode plate and the negative electrode plate. Since the lengths of the positive electrode plate and the negative electrode plate necessary for forming the electrode plate fluctuate, the positive electrode plate so that the portion of the negative electrode plate where the negative electrode active material layer is not formed outside is located on the outermost periphery of the electrode body. It is difficult to wind the negative electrode plate and the separator.

For this reason, in Patent Document 1, a portion where the negative electrode active material layer does not exist on the outer side of the negative electrode plate is formed longer, and the negative electrode active material layer on the outer side of the negative electrode plate exists by winding while confirming the winding state. By forming a negative electrode active material layer additionally in a portion not necessary, the above-described electrode body in which the outer negative electrode active material layer does not exist only at the outermost periphery of the electrode body is manufactured.
Alternatively, the negative electrode plate provided with the negative electrode active material layers on both sides in the entire longitudinal direction of the negative electrode plate is wound while confirming the winding state, and the negative electrode active material outside the outermost part of the negative electrode plate A method of forming the above-described electrode body in which the outer negative electrode active material layer does not exist only at the outermost periphery of the electrode body by peeling the layers is also conceivable.
However, in any of the methods, it is not easy to form an electrode body because it takes man-hours.

  The present invention has been made in view of the current situation, and the negative electrode active material layer in which the ions responsible for electrical conduction contained in the electrolyte solution are located on the outermost side of the electrode body and do not contribute to the charge / discharge reaction of the battery. It is an object of the present invention to provide a method for manufacturing a battery that can prevent or suppress the diffusion of the electrode body and can easily form an electrode body.

  One embodiment of the present invention for solving the above problems includes a stacked electrode body in which a plurality of positive plates and a plurality of negative plates are alternately stacked via a separator, and an electrolyte solution impregnated in the electrode body. The electrode body has an uppermost negative electrode plate that overlaps from the upper side through the separator on an uppermost positive electrode plate that is positioned on the uppermost side in the stacking direction among the positive electrode plates, and the positive electrode plates The lowermost layer positive electrode plate located on the lowermost side in the stacking direction has a lowermost layer negative electrode plate that overlaps from the lower side through the separator, and each of the plurality of positive electrode plates is a positive electrode current collector foil. And positive electrode active material layers formed on both surfaces of the positive electrode current collector foil, and the uppermost negative electrode plate is formed on the first negative electrode current collector foil and the lower surface of the first negative electrode current collector foil. And the uppermost positive electrode plate facing through the separator A first lower negative electrode active material layer that is larger than the positive electrode active material layer over the entire circumference, and has no negative electrode active material layer on the top surface of the first negative electrode current collector foil, or in the stacking direction. When the first lower negative electrode active material layer is projected, the first lower negative electrode active material layer has a smaller first upper negative electrode active material layer over the entire circumference than the first lower negative electrode active material layer. A current collector foil and a second upper negative electrode active material layer formed on the upper surface of the second negative electrode current collector foil and larger than the positive electrode active material layer of the lowermost positive electrode plate facing each other via the separator; The second upper negative electrode active material has no negative electrode active material layer on the lower surface of the second negative electrode current collector foil, or when the second upper negative electrode active material layer is projected in the stacking direction. Having a second lower negative electrode active material layer that is smaller than the entire circumference, Among the negative electrode plates, a plurality of inner negative plates located between the uppermost negative electrode plate and the lowermost negative electrode plate are formed on both sides of the third negative electrode current collector foil and the third negative electrode current collector foil, respectively. And a third negative electrode active material layer that is larger than the positive electrode active material layer opposed across the separator, and is larger than the positive electrode active material layer, and includes a plurality of positive electrode plates and a plurality of negative electrode plates. Layered alternately via the separator, the uppermost layer negative electrode plate overlaps the uppermost layer positive electrode plate via the separator from the upper side, and the lowermost layer negative electrode plate overlaps the lowermost layer positive electrode plate via the separator. An electrode body forming step for forming the electrode body in an overlapping form from the lower side, an assembly step for assembling the battery using the electrode body, and leaving the charged battery open in a terminal-open state, Voltage And a short-circuit detecting step for detecting the presence or absence of an internal short circuit of the battery based on the amount of decrease.

  The battery manufactured by the above-described manufacturing method includes a stacked electrode body. This electrode body does not have a negative electrode active material layer on the upper surface of the first negative electrode current collector foil of the uppermost negative electrode plate, or is smaller than the first lower negative electrode active material layer formed on the lower surface over the entire circumference. A first upper negative electrode active material layer is included. Also, the second lower side, which has no negative electrode active material layer on the lower surface of the second negative electrode current collector foil of the lowermost negative electrode plate, or is smaller than the second upper negative electrode active material layer formed on the upper surface over the entire circumference. It has a negative electrode active material layer. For this reason, in this battery, the ions contained in the electrolyte solution and responsible for electrical conduction are located on the outermost side of the electrode body and do not contribute to the charge / discharge reaction of the battery (the first upper side of the uppermost negative electrode plate). Diffusion to the negative electrode active material layer and the second lower negative electrode active material layer of the lowermost negative electrode plate can be prevented or suppressed.

In the battery manufacturing method described above, in the electrode body forming step, a plurality of positive plates and a plurality of negative plates including the uppermost negative plate, the lowermost negative plate and the inner negative plate are alternately arranged via separators. By laminating, the above-described electrode body is formed. As described above, in order to form the electrode body described in Patent Document 1, some device is required at the time of winding, and it was not easy to form the electrode body. Since it can form by laminating | stacking a some positive electrode plate and a some negative electrode plate alternately via a separator, formation of an electrode body is easy.
In addition, in the battery assembled in the assembly process, as described above, the ions included in the electrolyte and responsible for electrical conduction are the first upper negative electrode active material layer of the uppermost negative electrode plate and the second lower electrode of the lowermost negative electrode plate. Diffusion to the side negative electrode active material layer can be prevented or suppressed. For this reason, in a short circuit detection process, the time (self-discharge time) which leaves a battery in the state where the terminal was opened can be shortened, and the time required for the short circuit detection process can be shortened.

  Another aspect includes a stacked electrode body in which a plurality of positive plates and a plurality of negative plates are alternately stacked via a separator, and an electrolytic solution impregnated in the electrode body, and the electrode body includes: The uppermost positive electrode plate positioned on the uppermost side in the stacking direction of the plurality of positive electrode plates has an uppermost negative electrode plate that overlaps from the upper side with the separator interposed therebetween. The lowermost layer positive electrode plate located on the lower side has a lowermost layer negative electrode plate that overlaps from the lower side through the separator, and each of the plurality of positive electrode plates includes a positive electrode current collector foil and the positive electrode current collector foil. A positive electrode active material layer formed on each side of the first negative electrode current collector foil, the uppermost layer negative electrode plate is formed on the lower surface of the first negative electrode current collector foil, Than the positive electrode active material layer of the uppermost positive electrode plate facing A first lower negative electrode active material layer that has a large first lower negative electrode active material layer, and has no negative electrode active material layer on the upper surface of the first negative electrode current collector foil, or the first lower negative electrode active material in the stacking direction. When the layer is projected, the first upper negative electrode active material layer is smaller than the first lower negative electrode active material layer over the entire circumference, and the lowermost negative electrode plate includes the second negative electrode current collector foil and the second negative electrode current collector foil. A second upper negative electrode active material layer that is formed on the upper surface of the negative electrode current collector foil and is larger than the positive electrode active material layer of the lowermost positive electrode plate facing each other with the separator interposed therebetween. No negative electrode active material layer is formed on the lower surface of the negative electrode current collector foil, or when the second upper negative electrode active material layer is projected in the stacking direction, the second upper negative electrode active material layer is smaller than the second upper negative electrode active material layer. 2 having a lower negative electrode active material layer, of the plurality of negative electrode plates, A plurality of inner negative plates located between the layer negative electrode plate and the lowermost negative electrode plate are formed on the third negative electrode current collector foil and both surfaces of the third negative electrode current collector foil, respectively, and face each other via the separator And a third negative electrode active material layer that is larger than the positive electrode active material layer over the entire circumference.

  Since the above-described battery includes a laminated electrode body including the above-described uppermost layer negative electrode plate and lowermost layer negative electrode plate, ions included in the electrolyte solution and responsible for electrical conduction are located on the outermost side of the electrode body. Can be prevented or suppressed from diffusing into the negative electrode active material layer (the first upper negative electrode active material layer of the uppermost negative electrode plate and the second lower negative electrode active material layer of the lowermost negative electrode plate) that does not contribute to the charge / discharge reaction of .

It is a perspective view of the battery which concerns on Embodiment 1,2. 1 is a longitudinal sectional view of a battery according to Embodiments 1 and 2. FIG. 2 is a cross-sectional view of an electrode body according to Embodiment 1. FIG. 3 is a top view of a positive electrode plate according to Embodiments 1 and 2. FIG. 3 is a top view of an inner negative electrode plate according to Embodiments 1 and 2. FIG. About the uppermost layer negative electrode plate concerning Embodiment 1, (a) is a top view, (b) is a bottom view. (A) is a top view and (b) is a bottom view of the lowermost layer negative electrode plate according to Embodiment 1. 3 is a flowchart showing a method for manufacturing a battery according to Embodiment 1. 6 is a cross-sectional view of an electrode body according to Embodiment 2. FIG. About the uppermost layer negative electrode plate concerning Embodiment 2, (a) is a top view, (b) is a bottom view. (A) is a top view and (b) is a bottom view of the lowermost layer negative electrode plate according to Embodiment 2. It is a graph which shows the relationship between the elapsed time of self-discharge, and battery voltage about each battery of Embodiment 1, 2 and a comparative form. It is the graph which expanded the part enclosed with the broken line of FIG. The elapsed time from the measurement of the battery voltage V1, the voltage variation ΔVc of the voltage drop amount ΔV of each of the batteries of Embodiments 1 and 2, and the comparative example, and the voltage drop amount ΔV of the non-defective product and the voltage drop amount ΔV of the defective product It is a graph which shows the relationship with voltage difference (DELTA) Vd.

(Embodiment 1)
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. 1 and 2 are a perspective view and a longitudinal sectional view of a lithium ion secondary battery (hereinafter also simply referred to as “battery”) 1 according to the first embodiment. FIG. 3 shows a cross-sectional view of the electrode body 20. FIG. 4 shows a top view of the positive electrode plate 21. 5 shows a top view of the inner negative electrode plate 31C, FIG. 6 shows a top view and a bottom view of the uppermost negative electrode plate 31A, and FIG. 7 shows a top view and a bottom view of the lowermost negative electrode plate 31B. Show. In the following description, the battery thickness direction BH, the battery lateral direction CH, and the battery vertical direction DH of the battery 1 are defined as the directions shown in FIGS. 1 and 2.

  The battery 1 is a rectangular and sealed lithium ion secondary battery mounted on a vehicle such as a hybrid car, a plug-in hybrid car, or an electric car. The battery 1 includes a battery case 10, a stacked electrode body 20 accommodated therein, a positive terminal member 50 and a negative terminal member 60 supported by the battery case 10 (FIGS. 1 and 2). reference). In addition, a non-aqueous electrolyte (electrolytic solution) 19 is accommodated in the battery case 10, and a part thereof 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 the first embodiment). The battery case 10 is composed of a bottomed rectangular tube-shaped case main body member 11 that is open only on the upper side, and a rectangular plate-shaped case lid member 13 that is welded in a form that closes the opening of the case main body member 11. The A positive terminal member 50 made of aluminum is fixed to the case lid member 13 while being insulated from the case lid member 13. The positive electrode terminal member 50 is connected to and electrically connected to the positive electrode exposed portion 21m of the positive electrode plate 21 of the electrode body 20 in the battery case 10, and extends through the case lid member 13 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 and electrically connected to the negative electrode exposed portion 31m of the negative electrode plate 31 in the electrode body 20 in the battery case 10, and extends through the case lid member 13 to the outside of the battery.

  The electrode body 20 (see also FIG. 3) has a substantially rectangular parallelepiped shape, the stacking direction EH1 of the electrode body 20 matches the battery thickness direction BH, the electrode body lateral direction FH1 matches the battery lateral direction CH, The direction GH1 is accommodated in the battery case 10 so as to coincide with the battery vertical direction DH. Further, in this case, regarding the stacking direction EH1, in FIG. 3, the upper side is the upper side EA and the lower side is the lower side EB, but the gravity direction is not related to the upper side and the lower side. This electrode body 20 is formed by laminating a plurality of rectangular positive plates 21 and a plurality of rectangular negative plates 31 alternately in the laminating direction EH1 via separators 41 made of a rectangular porous resin film. Become.

  Specifically, in each positive electrode plate 21, the positive electrode plate thickness direction EH2 coincides with the stacking direction EH1 of the electrode body 20, the positive electrode plate lateral direction FH2 coincides with the electrode body lateral direction FH1, and the positive electrode plate longitudinal direction GH2 They are stacked in a form that matches the electrode body longitudinal direction GH1. In each negative electrode plate 31, the negative electrode plate thickness direction EH3 coincides with the stacking direction EH1 of the electrode body 20, the negative electrode plate lateral direction FH3 coincides with the electrode body lateral direction FH1, and the negative electrode plate longitudinal direction GH3 corresponds to the electrode body longitudinal direction. They are stacked in a form that matches the direction GH1. Further, the electrode body 20 includes an uppermost negative electrode plate 31 </ b> A that overlaps the uppermost EA via the separator 41 on the uppermost positive electrode plate 21 </ b> A located on the uppermost EA among the plurality of positive electrode plates 21. The electrode body 20 has a lowermost layer negative electrode plate 31 </ b> B that overlaps with the lowermost layer EB through the separator 41 on the lowermost layer positive electrode plate 21 </ b> B located on the lowermost side EB among the plurality of positive electrode plates 21.

  A plurality of positive electrode plates 21 (see FIGS. 4 and 3) including the uppermost positive electrode plate 21A and the lowermost positive electrode plate 21B are both surfaces (upper surface 22c and lower surface) of a positive electrode current collector foil 22 made of a rectangular aluminum foil. 22d), positive electrode active material layers 23 and 23 are provided in a rectangular shape in a region extending in the positive electrode plate vertical direction GH2 in a part (right side in FIG. 4) near the positive electrode plate horizontal direction FH2. The positive electrode active material layer 23 includes a positive electrode active material, a conductive material, and a binder. In the positive electrode plate 21, one end of the positive electrode plate lateral direction FH2 (the left end in FIG. 4) has no positive electrode active material layer 23 in the positive electrode plate thickness direction EH2, and the positive electrode current collector foil Reference numeral 22 denotes a positive electrode exposed portion 21m exposed in the positive electrode plate thickness direction EH2. The positive electrode exposed portion 21m of each positive electrode plate 21 is bundled in the stacking direction EH1 (positive electrode plate thickness direction EH2) and welded to the positive electrode terminal member 50 described above.

  Next, the negative electrode plate 31 will be described (see FIGS. 5 to 7 and 3). Between the aforementioned uppermost negative electrode plate 31A and lowermost negative electrode plate 31B, there are a plurality of inner negative electrode plates 31C. These inner negative plates 31C (see FIG. 5) are formed on both surfaces (upper surface 32c (32Cc) and lower surface 32d (32Cd)) of a negative electrode current collector foil 32 (third negative electrode current collector foil 32C) made of a rectangular copper foil. Among them, the negative electrode active material layers 33 and 33 (third negative electrode active material layers 33C and 33C) are rectangularly formed in a region (left side in FIG. 5) near the negative electrode plate lateral direction FH3 and extending in the negative electrode plate vertical direction GH3. It is provided in the shape. The third negative electrode active material layer 33 </ b> C is formed to be larger over the entire circumference than the positive electrode active material layer 23 of the positive electrode plate 21 opposed via the separator 41. The third negative electrode active material layer 33C includes a negative electrode active material, a binder, and a thickener. Of the inner negative electrode plate 31C, the other FH3B end portion (the right end portion in FIG. 5) of the negative electrode plate lateral direction FH3 does not have the third negative electrode active material layer 33C in the negative electrode plate thickness direction EH3. The negative electrode current collector foil 32C is a negative electrode exposed portion 31m exposed in the negative electrode plate thickness direction EH3.

  On the other hand, the uppermost negative electrode plate 31A (see FIG. 6) is a part of the lower surface 32Ad of the negative electrode current collector foil 32 (first negative electrode current collector foil 32A) made of a rectangular copper foil, close to the negative electrode plate lateral direction FH3. A negative electrode active material layer 33 (first lower negative electrode active material layer 33A2) is provided in a rectangular shape in a region extending in the negative electrode plate longitudinal direction GH3 (left side in FIG. 6). The first lower negative electrode active material layer 33A2 has a perimeter more than the positive electrode active material layer 23 of the uppermost positive electrode plate 21A opposed via the separator 41, like the third negative electrode active material layer 33C of the inner negative electrode plate 31C. Largely formed over. On the other hand, no negative electrode active material layer is provided on the upper surface 32Ac of the first negative electrode current collector foil 32A.

On the other hand, the lowermost negative electrode plate 31B (see FIG. 7) is a part of the upper surface 32Bc of the negative electrode current collector foil 32 (second negative electrode current collector foil 32B) made of a rectangular copper foil, close to the negative electrode plate lateral direction FH3. A negative electrode active material layer 33 (second upper negative electrode active material layer 33B1) is provided in a rectangular shape in a region extending in the negative electrode plate longitudinal direction GH3 (left side in FIG. 7). The second upper negative electrode active material layer 33B1 is opposed to the third negative electrode active material layer 33C of the inner negative electrode plate 31C and the first lower negative electrode active material layer 33A2 of the uppermost negative electrode plate 31A via the separator 41. It is larger than the positive electrode active material layer 23 of the lowermost positive electrode plate 21B over the entire circumference. On the other hand, no negative electrode active material layer is provided on the lower surface 32Bd of the second negative electrode current collector foil 32B.
The negative electrode exposed portion 31m of each negative electrode plate 31 (the uppermost negative electrode plate 31A, the lowermost negative electrode plate 31B, and the inner negative electrode plate 31C) is bundled in the stacking direction EH1 (negative electrode plate thickness direction EH3), and the negative electrode terminal member described above 60 is welded.

  As described above, the battery 1 of the first embodiment includes the stacked electrode body 20. In the electrode body 20, there is no negative electrode active material layer on the upper surface 32Ac of the first negative electrode current collector foil 32A of the uppermost negative electrode plate 31A, and the lower surface 32Bd of the second negative electrode current collector foil 32B of the lowermost negative electrode plate 31B. There is no negative electrode active material layer. For this reason, as will be described later, when the battery 1 is left to be discharged (self-discharge) with the terminals open in the short-circuit detection step S8 (see FIG. 8), the negative electrode active material layer 33 is provided. Lithium ions inserted into can be prevented from diffusing through the non-aqueous electrolyte 19 to the negative electrode active material layer that is located on the outermost side of the electrode body 20 and does not contribute to the charge / discharge reaction of the battery 1.

  Next, a method for manufacturing the battery 1 will be described (see FIG. 8). First, in the “positive electrode plate forming step S <b> 1”, a plurality of positive electrode plates 21 are manufactured. That is, a positive electrode active material, a conductive material, and a binder are kneaded together with a solvent to produce a positive electrode paste. And this positive electrode paste is apply | coated to the upper surface 22c of the positive electrode current collection foil 22 with a die-coat method, and it heat-drys, and forms the positive electrode active material layer 23. FIG. Similarly, a positive electrode paste is applied to the lower surface 22 d of the positive electrode current collector foil 22 and dried by heating to form the positive electrode active material layer 23. Thereafter, the positive electrode plate is compressed by a pressure roll to increase the density of the positive electrode active material layers 23 and 23. Thereby, the positive electrode plate 21 is formed.

  Separately, in the “negative electrode plate forming step S <b> 2”, a plurality of negative electrode plates 31 are manufactured. That is, a negative electrode active material, a binder, and a thickener are kneaded with a solvent to prepare a negative electrode paste. And about the inner side negative electrode plate 31C, this negative electrode paste is apply | coated to the upper surface 32Cc of the 3rd negative electrode current collector foil 32C by the die-coating method, and it heat-drys, and forms the 3rd negative electrode active material layer 33C. Similarly, a negative electrode paste is applied to the lower surface 32d of the third negative electrode current collector foil 32C, and is heated and dried to form the third negative electrode active material layer 33C. Thereafter, the inner negative electrode plate is compressed by a pressure roll to increase the density of the third negative electrode active material layers 33C and 33C. Thereby, the inner negative electrode plate 31C is formed.

For the uppermost negative electrode plate 31A, the above-described negative electrode paste is applied to the lower surface 32Ad of the first negative electrode current collector foil 32A and dried by heating to form the first lower negative electrode active material layer 33A2. On the other hand, no negative electrode active material layer is formed on the upper surface 32Ac of the first negative electrode current collector foil 32A. Thereafter, the negative electrode plate is compressed to increase the density of the first lower negative electrode active material layer 33A2. As a result, the uppermost negative electrode plate 31A is formed.
For the lowermost negative electrode plate 31B, the above-described negative electrode paste is applied to the upper surface 32Bc of the second negative electrode current collector foil 32B and dried by heating to form the second upper negative electrode active material layer 33B1. On the other hand, the negative electrode active material layer is not formed on the lower surface 32Bd of the second negative electrode current collector foil 32B. Thereafter, the negative electrode plate is compressed to increase the density of the second upper negative electrode active material layer 33B1. Thereby, the lowermost negative electrode plate 31B is formed.

  Next, in “electrode body forming step S3”, the electrode body 20 is formed. Specifically, a plurality of positive plates 21 and a plurality of negative plates 31 are alternately stacked via separators 41. The uppermost layer positive electrode plate 21A of the uppermost EA among the plurality of positive electrode plates 21 is overlaid with the uppermost layer negative electrode plate 31A from the upper side EA via the separator 41, and the lowermost layer of the lowermost EB of the plurality of positive electrode plates 21 On the positive electrode plate 21 </ b> B, the lowermost layer negative electrode plate 31 </ b> B is stacked from the lower side EB via the separator 41 to form the stacked electrode body 20.

  Next, in “assembly step S4”, the battery 1 is assembled. Specifically, the positive terminal member 50 and the negative terminal member 60 are fixed to the case lid member 13 (see FIGS. 1 and 2). Furthermore, the positive electrode terminal member 50 and the negative electrode terminal member 60 are welded to the electrode body 20, respectively. Thereafter, the electrode body 20 is 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 battery case 10 is formed by laser welding the case main body member 11 and the case lid member 13. Thereafter, the nonaqueous electrolytic solution 19 is injected into the battery case 10 from the injection hole 13 h provided in the case lid member 13 and impregnated in the electrode body 20, and then injected into the electrode body 20 with the sealing member 15. Is sealed.

Next, the battery 1 is restrained prior to performing the “initial charging step S5”. Specifically, the wide side surface of the battery case 10 is sandwiched in the battery thickness direction BH by a pair of plate-shaped pressing jigs, and the battery 1 is restrained while being pressed in the battery thickness direction BH. In the present embodiment, the “initial charging step S5” to the “short circuit detection step S8” described below are performed in a state where the battery 1 is restrained in this manner.
After the battery 1 is restrained, the battery 1 is initially charged in the “initial charging step S5”. Specifically, a charging / discharging device is connected to the battery 1 and is initially charged to SOC 100% by constant current constant voltage charging (CCCV charging) at room temperature (25 ± 5 ° C.).

  Next, in the “high temperature aging step S <b> 6”, the battery 1 is left at a high temperature for aging. Specifically, the battery 1 after initial charging is left to age for 20 hours with the terminals open at a temperature of 50 to 80 ° C. (60 ° C. in the present embodiment).

  Next, in “SOC adjustment step S7”, the battery 1 is discharged to adjust the SOC value. Specifically, a charging / discharging device is connected to the battery 1 to forcibly discharge to SOC 0% at room temperature (25 ± 5 ° C.).

  Next, in “short circuit detection step S <b> 8”, the voltage drop amount ΔV due to self-discharge is acquired, and the presence or absence of an internal short circuit of the battery 1 is detected. Specifically, the battery 1 is left (self-discharged) at room temperature (25 ± 5 ° C.) with the terminals open and for a predetermined leaving time (8.0 days in this embodiment). The battery voltage V1 at the time 1.0 days after the start of the self-discharge and the battery voltage V2 at the end of the self-discharge (after 8.0 days and 7.0 days after the measurement of the battery voltage V1) are measured. Thus, the voltage drop amount ΔV = V1−V2 is calculated.

  The battery voltage increases conversely immediately after the end of the “SOC adjustment step S7” (see FIGS. 12 and 13), and after about one day has elapsed since the start of self-discharge in the “short circuit detection step S8”. As described above, the measurement of the battery voltage V1 was performed 1.0 day after the start of self-discharge. Specifically, when the voltage drop amount per unit time after 3.0 days from the start of self-discharge is ΔVt, the first time when the voltage drop amount per unit time becomes ΔVt / 2 is measured for the battery voltage V1. Time (= 1.0 day).

  Then, the voltage drop amount ΔV of the battery 1 is compared with the reference voltage drop amount ΔVa. When the voltage drop amount ΔV is larger than the reference voltage drop amount ΔVa (ΔV> ΔVa), an internal short circuit occurs in the battery 1. The battery 1 is removed. On the other hand, when the voltage drop amount ΔV of the battery 1 is smaller than the reference voltage drop amount ΔVa (ΔV ≦ ΔVa), the battery 1 is determined to be normal (a non-defective product without an internal short circuit). Thus, the battery 1 is completed.

  As described above, in the manufacturing method of the battery 1 described above, in the electrode body forming step S3, a plurality of positive plates 21, a plurality of uppermost negative plates 31A, a lowermost negative plate 31B, and a plurality of inner negative plates 31C are included. The electrode body 20 is formed by alternately laminating the negative electrode plates 31 with the separators 41 interposed therebetween. As described above, in order to form the electrode body described in Patent Document 1, some device is required at the time of winding, and it is not easy to form the electrode body. Since the plurality of positive plates 21 and the plurality of negative plates 31 can be alternately stacked via the separators 41 in S3, the electrode body 20 can be easily formed.

  In addition, the battery 1 assembled in the assembly step S4 is, as will be described later, in the short circuit detection step S8, when the battery 1 is left to discharge (self-discharge) with the terminals open, the negative electrode active material layer 33 Lithium ions inserted into can be prevented from diffusing through the non-aqueous electrolyte 19 to the negative electrode active material layer that is located on the outermost side of the electrode body 20 and does not contribute to the charge / discharge reaction of the battery 1. This is because such a negative electrode active material layer does not exist. For this reason, in the short-circuit detection step S8, as will be described later, it is possible to shorten the time (self-discharge time: 8.0 days in the first embodiment) in which the battery 1 is left with the terminals open, and the short-circuit detection step S8 is started. Time can be shortened.

(Embodiment 2)
Next, a second embodiment will be described. In contrast to the battery 1 of the first embodiment, in the battery 101 of the second embodiment, the uppermost negative electrode plate 131A (see FIG. 10) and the lowermost negative electrode plate 131B (see FIG. 11) of the stacked electrode body 120 (see FIG. 9). The form of reference) is different. Other than that is the same as the battery 1 of the first embodiment.

  Specifically, in the uppermost layer negative electrode plate 31A of Embodiment 1, the negative electrode active material layer was not formed on the upper surface 32Ac of the first negative electrode current collector foil 32A (see FIG. 6A). On the other hand, in the uppermost layer negative electrode plate 131A of Embodiment 2, the first upper negative electrode active material layer 133A1 is also formed on the upper surface 32Ac of the first negative electrode current collector foil 32A (see FIG. 10A). . However, the first upper negative electrode active material layer 133A1 is obtained when the first lower negative electrode active material layer 33A2 (see FIG. 10B) formed on the lower surface 32Ad is projected in the stacking direction EH1 (negative electrode plate thickness direction EH3). As shown by a broken line in FIG. 10A, the first lower negative electrode active material layer 33A2 is formed smaller by being pulled down by 10.0 mm or more (10.0 mm in the second embodiment) over the entire circumference. Yes.

  The uppermost negative electrode plate 131A is manufactured as follows. That is, first, as in the first embodiment, the negative electrode paste is applied to the lower surface 32Ad of the first negative electrode current collector foil 32A, and is heated and dried to form the first lower negative electrode active material layer 33A2. Thereafter, the negative electrode paste is also applied to the upper surface 32Ac of the first negative electrode current collector foil 32A, and is heated and dried to form the first upper negative electrode active material layer 133A1. Thereafter, the uppermost negative electrode plate 131A is formed by compressing it.

  Further, in the lowermost layer negative electrode plate 31B of Embodiment 1, the negative electrode active material layer was not formed on the lower surface 32Bd of the second negative electrode current collector foil 32B (see FIG. 7B). On the other hand, in the lowermost layer negative electrode plate 131B of Embodiment 2, the second lower negative electrode active material layer 133B2 is also formed on the lower surface 32Bd of the second negative electrode current collector foil 32B (see FIG. 11B). ). However, the second lower negative electrode active material layer 133B2 is obtained when the second upper negative electrode active material layer 33B1 (see FIG. 11A) formed on the upper surface 32Bc is projected in the stacking direction EH1 (negative electrode plate thickness direction EH3). 11B, the second upper negative electrode active material layer 33B1 is formed smaller than the second upper negative electrode active material layer 33B1 by being lowered by 10.0 mm or more (10.0 mm in the second embodiment). .

  The lowermost negative electrode plate 131B is manufactured as follows. That is, first, similarly to the first embodiment, the negative electrode paste is applied to the upper surface 32Bc of the second negative electrode current collector foil 32B, and is heated and dried to form the second upper negative electrode active material layer 33B1. Thereafter, the negative electrode paste is also applied to the lower surface 32Bd of the second negative electrode current collector foil 32B, and dried by heating to form the second lower negative electrode active material layer 133B2. Then, the lowest layer negative electrode plate 131B is formed by compressing this.

  As described above, the battery 101 according to the second embodiment also includes the stacked electrode body 120. The electrode body 120 has a first upper negative electrode active material layer 133A1 that is smaller than the first lower negative electrode active material layer 33A2 on the upper surface 32Ac of the first negative electrode current collector foil 32A of the uppermost negative electrode plate 131A. In addition, the second lower negative electrode active material layer 133B2 that is smaller than the second upper negative electrode active material layer 33B1 is provided on the lower surface 32Bd of the second negative electrode current collector foil 32B of the lowermost negative electrode plate 131B. For this reason, as will be described later, in the battery 101, when the battery 101 is self-discharged in the short circuit detection step S8, the lithium ions inserted into the negative electrode active material layer 33 are passed through the non-aqueous electrolyte 19 to the electrode body. It is possible to suppress diffusion to the first upper negative electrode active material layer 133 </ b> A <b> 1 and the second lower negative electrode active material layer 133 </ b> B <b> 2 that are located on the outermost side of 20 and do not contribute to the charge / discharge reaction of the battery 1.

  The manufacturing method of the battery 101 of the second embodiment is the same as the manufacturing method of the battery 1 of the first embodiment except for the formation of the uppermost negative electrode plate 131A and the lowermost negative electrode plate 131B described above. Therefore, also in the manufacture of the battery 101 of the second embodiment, the electrode body 120 can be easily formed in the electrode body forming step S3. Further, in the short circuit detection step S8, as will be described later, the time for which the battery 101 is left with the terminals opened (self-discharge time: 8.0 days in the second embodiment) can be shortened, and the time required for the short circuit detection step S8. Can be shortened.

(Test results)
Subsequently, the result of the test conducted in order to verify the effect of this invention is demonstrated. A plurality (n = 100) of the batteries 1 of Embodiment 1 were manufactured. As described above, the battery 1 of Embodiment 1 has no negative electrode active material layer on the upper surface 32Ac of the first negative electrode current collector foil 32A of the uppermost negative electrode plate 31A, and the second negative electrode of the lowermost negative electrode plate 31B. There is no negative electrode active material layer on the lower surface 32Bd of the current collector foil 32B (see FIG. 3 and the like).
A plurality (n = 100) of the batteries 101 of the second embodiment were manufactured. As described above, the battery 101 of Embodiment 2 is pulled down 10.0 mm over the entire circumference of the upper surface 32Ac of the first negative electrode current collector foil 32A of the uppermost negative electrode plate 131A from the first lower negative electrode active material layer 33A2. A small first upper negative electrode active material layer 133A1 is provided (see FIG. 9 and the like). Further, a small second lower negative electrode active material layer 133B2 that is pulled down 10.0 mm over the entire circumference of the second upper negative electrode active material layer 33B1 on the lower surface 32Bd of the second negative electrode current collector foil 32B of the lowermost layer negative electrode plate 131B. Have.

On the other hand, as a comparative example (see FIG. 3), the batteries 1 and 101 of the first and second embodiments are different from the batteries 1 and 101 in the manufacture of a plurality (n = 100) of batteries having different forms of the uppermost negative electrode plate 931A and lowermost negative electrode plate 931B. did. In this comparative battery, the uppermost negative electrode plate 931A and the lowermost negative electrode plate 931B are the same as the inner negative electrode plate 31C. That is, the first upper negative electrode active material layer 33A2 having the same size as the first lower negative electrode active material layer 33A2 is also formed on the upper surface 32Ac of the first negative electrode current collector foil 32A of the uppermost negative electrode plate 931A, as indicated by a broken line in FIG. A material layer 933A1 is included. In addition, the lower surface 32Bd of the second negative electrode current collector foil 32B of the lowermost layer negative electrode plate 931B also has a second lower negative electrode active material having the same size as the second upper negative electrode active material layer 33B1, as indicated by a broken line in FIG. A material layer 933B2 is included.
In this test, for each of the batteries of the first and second embodiments and the comparative embodiment, the measurement of the battery voltage V2 is measured from the measurement of the battery voltage V1, as in the short-circuit detection step S8, separately from the short-circuit detection step S8. After a sufficiently long time (specifically, 30.0 days), the voltage drop amount ΔV = V1−V2 is calculated, and the presence / absence of an internal short circuit is determined from the magnitude of the voltage drop amount ΔV (battery quality) Judgment). Thus, the “non-defective battery group” and the “defective battery group” described below were distinguished afterwards, and the following were examined retrospectively from the survey results.

  In the manufacturing process of each battery of the first and second embodiments and the comparative embodiment, the relationship between the elapsed time of self-discharge in the short circuit detection step S8 and the battery voltage was investigated. For each of the first and second embodiments and the comparative embodiment, an average battery is selected from the aforementioned “good battery group” determined not to have an internal short circuit, and the results are shown in FIGS. It is shown in FIG. FIG. 13 is an enlarged graph of a portion surrounded by a broken line in FIG. Moreover, in FIG.12 and FIG.13, the battery voltage of the battery 1 of Embodiment 1 1.0 days after the start of self-discharge is shown as a reference (= 0 mV).

  First, as is clear from FIG. 13, in the comparative average quality battery, it takes about 1.3 days from the start of self-discharge until the battery voltage rises to a peak, and then the battery voltage gradually decreases. I will do it. On the other hand, in each of the average non-defective batteries 1 and 101 of Embodiments 1 and 2, it took only about 0.9 days from the start of self-discharge until the increase in battery voltage reached a peak. The battery voltage gradually decreases. Therefore, in the batteries 1 and 101 of the first and second embodiments, the measurement timing of the first battery voltage V1 for calculating the voltage drop amount ΔV in the short circuit detection step S8 can be made earlier than the battery of the comparative form. The standby time from the start of self-discharge to the measurement of the battery voltage V1 can be shortened.

  In addition, it is considered that the reason why the time from the start of self-discharge until the rise of the battery voltage reaches the peak is shorter in the batteries 1 and 101 of the first and second embodiments than in the comparative battery is as follows. . That is, the battery of the comparative example has the first upper negative electrode active material layer 933A1 on the uppermost negative electrode plate 931A and the second lower negative electrode active material layer 933B2 on the lowermost negative electrode plate 931B. Therefore, after completion of the SOC adjustment step S7, lithium ions present in the first upper negative electrode active material layer 933A1 of the uppermost negative electrode plate 931A and in the second lower negative electrode active material layer 933B2 of the lowermost negative electrode plate 931B. However, it gradually diffuses through the non-aqueous electrolyte 19 to the negative electrode active material layer 33 facing the positive electrode active material layer 23 over time. For this reason, the time from the start of self-discharge until the rise in battery voltage reaches a peak becomes longer.

  On the other hand, in the battery 1 of Embodiment 1, the first upper negative electrode active material layer does not exist in the uppermost negative electrode plate 31A, and the second lower negative electrode active material layer does not exist in the lowermost negative electrode plate 31B. The diffusion of lithium ions as in the comparative example cannot occur. In the battery 101 of the second embodiment, the first upper negative electrode active material layer 133A1 of the uppermost negative electrode plate 131A is pulled down by 10.0 mm over the entire circumference, and the second lower negative electrode active material layer 133B2 of the lowermost negative electrode plate 131B is reduced. Since the entire circumference is lowered by 10.0 mm, the lithium ions present in the first upper negative electrode active material layer 133A1 and the second lower negative electrode active material layer 133B2 are in contact with the negative electrode active material layer 23. Difficult to diffuse to material layer 33. For this reason, it is considered that the batteries 1 and 101 of Embodiments 1 and 2 have a shorter time from the start of self-discharge until the rise in battery voltage reaches a peak than the batteries of the comparative embodiments.

  Specifically, as described in the first embodiment, for example, the voltage drop amount per unit time after 3.0 days from the start of self-discharge is ΔVt, and the voltage drop amount per unit time is ΔVt / 2. When the battery voltage V1 is measured as the first time, the standby time from the start of self-discharge until the battery voltage V1 is measured is shown in Table 1, FIG. 12, and FIG. 1.5 days. On the other hand, in each of the batteries 1 and 101 of Embodiments 1 and 2, this standby time is 1.0 day. Therefore, in the first and second embodiments, the standby time from the start of self-discharge to the measurement of the battery voltage V1 can be shortened by 1.5−1.0 = 0.5 days compared to the comparative embodiment.

  Further, as apparent from FIG. 12, when the increase in the battery voltage reaches a peak, the average battery of the non-defective product of the comparative form greatly decreases as the self-discharge time elapses. Compared to the above, in the good average batteries 1 and 101 of Embodiments 1 and 2, the amount of decrease in battery voltage is small. Specifically, in the average battery of the non-defective product of the comparative form, for example, the voltage drop amount ΔV for 4.0 days from 2.0 days to 6.0 days after the start of self-discharge is ΔV = 29.4 ( On the other hand, in the non-defective average batteries 1 and 101 of the first and second embodiments, the voltage drop amount ΔV for 4.0 days was as small as ΔV = 5.6 (mV). It was.

  The reason why the voltage drop amount ΔV is smaller in the batteries 1 and 101 of the first and second embodiments than in the battery of the comparative example is considered as follows. In other words, in the comparative battery, lithium ions inserted into the negative electrode active material layer 33 facing the positive electrode active material layer 23 through the separator 41 pass through the nonaqueous electrolyte 19 during self-discharge, and the uppermost negative electrode plate 931A. The first upper negative electrode active material layer 933A1 and the second lower negative electrode active material layer 933B2 of the lowermost negative electrode plate 931B are largely diffused. Then, as the lithium ions are released from the negative electrode active material layer 33, the negative electrode potential of the negative electrode plate increases, and the battery voltage decreases accordingly. For this reason, in the battery of a comparative form, even if it is a good battery which does not have an internal short circuit, voltage drop amount (DELTA) V becomes large.

  On the other hand, in the battery 1 of Embodiment 1, the first upper negative electrode active material layer does not exist in the uppermost negative electrode plate 31A, and the second lower negative electrode active material layer does not exist in the lowermost negative electrode plate 31B. For this reason, lithium ions inserted into the negative electrode active material layer 33 facing the positive electrode active material layer 23 via the separator 41 pass through the non-aqueous electrolyte 19 during the self-discharge and pass through the first upper negative electrode active material layer and the second It does not diffuse into the lower negative electrode active material layer. For this reason, due to the diffusion of lithium ions into the first upper negative electrode active material layer and the second lower negative electrode active material layer, lithium ions escape from the negative electrode active material layer 33 and the negative electrode potential of the negative electrode plate 31 increases. It is possible to prevent the battery voltage from decreasing. For this reason, in the battery 1 of Embodiment 1, the amount of voltage drop ΔV during self-discharge was small.

  In the battery 101 of the second embodiment, the first upper negative electrode active material layer 133A1 of the uppermost negative electrode plate 31A and the second lower negative electrode active material layer 133B2 of the lowermost negative electrode plate 31B are each lowered by 10.0 mm over the entire circumference. It is formed small. Therefore, the first upper negative electrode active material layer in which lithium ions inserted into the negative electrode active material layer 33 facing the positive electrode active material layer 23 through the separator 41 are pulled down through the non-aqueous electrolyte 19 during self-discharge. The diffusion to 133A1 and the second lower negative electrode active material layer 133B2 is suppressed. For this reason, due to the diffusion of lithium ions into the first upper negative electrode active material layer 133A1 and the second lower negative electrode active material layer 133B2, lithium ions are released from the negative electrode active material layer 33, and the negative electrode potential of the negative electrode plate 31 is reduced. It can suppress that it becomes high and a battery voltage falls. For this reason, in the battery 101 of the second embodiment, it is considered that the voltage drop amount ΔV during self-discharge is small.

  As described above, in the comparative battery, the voltage drop ΔV is large in a non-defective battery, but when the voltage drop ΔV is large in the non-defective battery as described above, the voltage of the voltage drop ΔV in the non-defective battery group. The variation ΔVc also tends to increase. The investigation results are shown in FIG. In FIG. 14, the average value ΔVm of the voltage drop amount ΔV is obtained for the non-defective battery group of the comparative form at that time, and the battery having the largest voltage drop amount ΔV among the good battery groups (that is, The battery closest to the defective product in the non-defective battery group (the voltage drop amount of this battery is assumed to be ΔVh) is selected, and the difference (ΔVh−ΔVm) is set as the voltage variation ΔVc.

  As can be seen from FIG. 14, in the non-defective battery group of the comparative form, when the elapsed time (inspection discharge time) from the measurement of the battery voltage V1 to the measurement of the battery voltage V2 is 7.0 days, the voltage drop amount ΔV is The voltage variation ΔVc was 0.49 mV, the elapsed time was 15.0 days, the voltage variation ΔVc was 0.81 mV, and the elapsed time was 19.0 days, and the voltage variation ΔVc was 0.98 mV.

  In the first and second embodiments, as in the comparative example described above, the voltage variation ΔVc (= ΔVh−ΔVm) of the voltage drop amount ΔV in each non-defective battery group was investigated (see FIG. 14). As can be seen from FIG. 14, in each of the good battery groups of Embodiments 1 and 2, when the elapsed time (inspection discharge time) is 7.0 days, the voltage variation ΔVc of the voltage drop amount ΔV is 0. It was only 30 mV.

  Regarding the battery 1 of the first embodiment, the relationship between the elapsed time from the measurement of the battery voltage V1 and the voltage difference ΔVd between the voltage drop amount ΔV of the non-defective battery group and the voltage drop amount ΔV of the defective battery group. Also investigated. Specifically, the above-described average value ΔVm of the voltage drop amount ΔV of the non-defective battery group and the battery 1 having the smallest voltage drop amount ΔV among the defective battery groups (that is, in the defective battery group) The voltage difference ΔVd = ΔVi−ΔVm with respect to the voltage drop amount ΔVi of the battery 1) closest to the non-defective product was also investigated. In addition, when the batteries of the embodiment 2 and the comparative embodiment were also investigated in the same manner, the same result as that of the battery 1 of the embodiment 1 was obtained. The result is shown in FIG.

  Here, when the elapsed time (inspection discharge time) is 7.0 days, in the non-defective battery group of the comparative form, the voltage variation ΔVc = 0.49 mV of the voltage drop amount ΔV, which is different from the above-mentioned non-defective products. The voltage difference ΔVd of the voltage drop ΔV of the non-defective product is larger than 0.36 mV. At this time, for example, the voltage drop amount ΔVh of the battery closest to the defective product in the non-defective battery group is ΔVh = ΔVm + 0.49 (mV) from Vc = ΔVh−ΔVm = 0.49 (mV). . On the other hand, the voltage drop amount ΔVi of the battery closest to the non-defective battery in the defective battery group is ΔVi = ΔVm + 0.36 (mV) from Vd = ΔVi−ΔVm = 0.36 (mV). Therefore, the voltage drop amount ΔVh (= ΔVm + 0.49) of the battery closest to the defective product in the non-defective battery group is the voltage drop amount ΔVi (= Vi of the battery closest to the non-defective product in the defective battery group. ΔVm + 0.36) (ΔVh> ΔVi). That is, at the time when 7.0 days have passed, some of the batteries determined to be non-defective after 30.0 days from the measurement of the battery voltage V1 are determined to be defective after 30.0 days. The voltage drop amount ΔV is larger than that. Therefore, at the time when 7.0 days have elapsed, it is not possible to appropriately determine whether the battery is good or bad.

  Next, when the elapsed time (inspection discharge time) is 15.0 days, in the non-defective battery group of the comparative form, the voltage variation ΔVc = 0.81 mV of the voltage drop ΔV, which is different from the above-mentioned non-defective products. The voltage difference ΔVd of the voltage drop ΔV of the non-defective product is larger than 0.77 mV. Therefore, even after the passage of 15.0 days, the voltage drop amount ΔV for some of the batteries that are later determined to be non-defective products is larger than that of the batteries that are subsequently determined to be defective. It is not possible to make an appropriate judgment.

  On the other hand, when the elapsed time (inspection discharge time) is 19.0 days, in the non-defective battery group of the comparative form, the voltage variation ΔVc = 0.98 mV of the voltage drop ΔV. The voltage difference ΔVd of the voltage drop amount ΔV is less than 0.99 mV. At this time, the voltage drop amount ΔVh of the battery closest to the defective product in the non-defective battery group is ΔVh = ΔVm + 0.98 (mV). On the other hand, the voltage drop amount ΔVi of the battery closest to the non-defective product in the defective battery group is ΔVi = ΔVm + 0.99 (mV). Accordingly, the voltage drop amount ΔVh (= ΔVm + 0.98) of the battery closest to the defective product in the non-defective battery group is the voltage drop amount ΔVi (= Vi) of the battery closest to the good product in the defective battery group. Smaller than (ΔVm + 0.99) (ΔVh <ΔVi). That is, at this time, the voltage drop amount ΔV of all batteries that are later determined to be non-defective products is smaller than the voltage drop amount ΔV of any battery that is subsequently determined to be defective. In other words, the same result can be obtained without waiting for 30.0 days from the measurement of the battery voltage V1 or by determining whether the battery is good after 19.0 days have passed. From this, in the comparative battery, as shown in Table 1, the inspection discharge time can be set to 19.0 days.

  On the other hand, in the non-defective battery groups of Embodiments 1 and 2, when the elapsed time (inspection discharge time) is 7.0 days, the voltage variation ΔVc of the voltage drop amount ΔV is only 0.30 mV, which is described above. The voltage difference ΔVd of the voltage drop amount ΔV between the good product and the defective product is smaller than 0.36 mV. The voltage drop amount ΔVh of the battery 1,101 closest to the defective product in the non-defective battery group is ΔVh = ΔVm + 0.30 (mV). On the other hand, the voltage drop amount ΔVi of the battery closest to the non-defective product in the defective battery group is ΔVi = ΔVm + 0.36 (mV). Therefore, the voltage drop ΔVh (= ΔVm + 0.30) of the battery 1,101 closest to the defective product in the non-defective battery group is the voltage drop amount ΔVi ( = ΔVm + 0.36) (ΔVh <ΔVi). That is, at the time when 7.0 days have passed, any battery 1 in which the voltage drop amount ΔV of all the batteries 1,101 determined to be non-defective after 30.0 days is determined to be defective after 30.0 days. , 101 is smaller than the voltage drop amount ΔV. For this reason, the quality of the battery can be properly determined already at the time when 7.0 days have elapsed. From this, in the batteries 1 and 101 of Embodiments 1 and 2, as shown in Table 1, the inspection discharge time can be set to 7.0 days. Thus, in the batteries 1 and 101 of the first and second embodiments, the inspection discharge time can be shortened by 19.0−7.0 = 12.0 days compared to the battery of the comparative example.

  As described above, in the batteries 1 and 101 of the first and second embodiments, the waiting time from the start of self-discharge to the measurement of the battery voltage V1 can be shortened by 0.5 days compared to the battery of the comparative example. The overall self-discharge time in the detection step S8 can be shortened by 0.5 + 12.0 = 12.5 days compared to the comparative battery.

  In the above, the present invention has been described with reference to the first and second embodiments. However, the present invention is not limited to the above-described first and second embodiments, and can be appropriately modified and applied without departing from the gist thereof. Needless to say, you can.

1,101 Battery 19 Non-aqueous electrolyte (electrolyte)
20, 120 Electrode body 21 Positive electrode plate 21A Uppermost layer positive electrode plate 21B Lowermost layer positive electrode plate 22 Positive electrode current collector foil 22c Upper surface 22d Lower surface 23 Positive electrode active material layer 31 Negative electrode plate 31A, 131A Uppermost layer negative electrode plate 31B, 131B Lowermost layer negative electrode plate 31C Inner negative electrode plate 32 Negative electrode current collector foil 32c Upper surface 32d Lower surface 32A First negative electrode current collector foil 32Ac (First negative electrode current collector foil) Upper surface 32Ad (First negative electrode current collector foil) Lower surface 32B Second negative electrode current collector foil 32Bc ( Upper surface 32Bd (of the second negative electrode current collector foil) lower surface 32C (Second negative electrode current collector foil) lower surface 32C Third negative electrode current collector foil 32Cc (third negative electrode current collector foil) upper surface 32Cd (third negative electrode current collector foil) lower surface 33 Negative active material layer 33A2 First lower negative active material layer 133A1 First upper negative active material layer 33B1 Second upper negative active material layer 133B2 Second lower negative active material layer 33C Third negative active material layer 41 Separate Data EH1 stacking direction EA (out of stacking direction) upper side EB (out of stacking direction) lower side S3 electrode body forming step S4 assembling step S8 short circuit detecting step V1, V2 battery voltage ΔV voltage drop amount

Claims (1)

A laminate type electrode body in which a plurality of positive electrode plates and a plurality of negative electrode plates are alternately laminated via a separator, and an electrolyte solution impregnated in the electrode body,
The electrode body is
The uppermost positive electrode plate positioned on the uppermost side in the stacking direction of the plurality of positive electrode plates has an uppermost negative electrode plate that overlaps from the upper side with the separator interposed therebetween. The lowermost layer positive electrode plate located on the lower side has the lowermost layer negative electrode plate overlapping from the lower side through the separator,
The plurality of positive electrode plates are all
A positive electrode current collector foil, and positive electrode active material layers respectively formed on both surfaces of the positive electrode current collector foil,
The uppermost negative electrode plate is
A first negative electrode current collector foil and a first lower negative electrode formed on the lower surface of the first negative electrode current collector foil and larger than the positive electrode active material layer of the uppermost positive electrode plate opposed via the separator over the entire circumference An active material layer,
When the upper surface of the first negative electrode current collector foil does not have a negative electrode active material layer, or when the first lower negative electrode active material layer is projected in the stacking direction, the first lower negative electrode active material layer is more than the first lower negative electrode active material layer. Having a small first upper negative electrode active material layer over the entire circumference,
The lowermost negative electrode plate is
A second negative electrode current collector foil, and a second upper negative electrode active material formed on the upper surface of the second negative electrode current collector foil and larger than the positive electrode active material layer of the lowermost positive electrode plate facing each other with the separator interposed therebetween. In addition to having a material layer,
There is no negative electrode active material layer on the lower surface of the second negative electrode current collector foil, or when the second upper negative electrode active material layer is projected in the stacking direction, the entire circumference is more than the second upper negative electrode active material layer. A small second lower negative electrode active material layer,
Among the plurality of negative electrode plates, the plurality of inner negative electrode plates positioned between the uppermost negative electrode plate and the lowermost negative electrode plate,
A third negative electrode current collector foil, and a third negative electrode active material layer formed on both surfaces of the third negative electrode current collector foil and larger than the positive electrode active material layer facing each other with the separator interposed therebetween. A battery manufacturing method comprising:
The plurality of positive electrode plates and the plurality of negative electrode plates are alternately stacked via the separator, and the uppermost layer positive electrode plate overlaps the uppermost layer positive electrode plate via the separator from above, and the lowermost layer positive electrode plate An electrode body forming step of forming the electrode body in a form in which the lowermost negative electrode plate overlaps from the lower side via the separator;
An assembly step of assembling the battery using the electrode body;
A short-circuit detection step of leaving the charged battery in a terminal-opened state and detecting the presence or absence of an internal short-circuit of the battery based on the amount of voltage drop of the battery voltage.

Images