JP5089176B2 - Control valve type lead storage battery manufacturing method - Google Patents

Description

The present invention is a control produced by storing a positive electrode plate and a negative electrode plate containing carbon alternately in a battery case in a state of high pressure, and forming a battery case. The present invention relates to a method for manufacturing a valve-type lead-acid battery.

Conventionally, lead-acid batteries can be broadly classified into two types: liquid-type lead-acid batteries and control-valve-type lead-acid batteries. Of these, the control-valve-type lead-acid batteries include a positive electrode plate in which an active material paste is filled in a lead-based substrate. After forming the negative electrode plate unformed or in a dedicated chemical tank, and alternately laminating them through a mat-like separator mainly composed of fine glass fibers to form a plate group, The ears are connected by welding to form an electrode plate group, which is stored in the battery case in a compressed state, and a lid having an opening for injecting and exhausting is adhered to the battery case with welding or an adhesive. The electrolyte is injected so that the liquid surface height is about 110% of the electrode plate group height excluding the electrode plate ears, and if the positive and negative electrode plates are not formed, a battery case is formed. It is manufactured by covering a rubber valve (control valve) over an opening for liquid or exhaust. The control valve type lead-acid battery produced in this way is a lead-acid battery that eliminates the need for water replenishment by absorbing oxygen generated at the positive electrode at the time of overcharging, and is sealed in various fields. It is used in.

In recent years, control valve type lead-acid batteries that do not require replenishment, replenishment of electrolyte, and the like are becoming mainstream from the viewpoint of maintenance-free, and the penetration rate is rapidly expanding. For this reason, improvements are being made to withstand cycle use that repeats deep charge and discharge for power storage, as compared to float use such as backup of communication equipment. In such applications, the life of the lead-acid battery is often extended by softening and mudification of the positive electrode active material. To suppress this and improve the adhesion between the grid and the active material, the electrode plate group is placed in the battery case. It is inserted in a compressed state of about 40 kPa.

In addition, when storing natural energy such as sunlight or wind power in a storage battery, the cycle is often repeated in a partially charged state (PSOC; Partial State Of Charge), and the life of the lead storage battery is reduced by sulfation of the negative electrode active material. Sometimes. For this reason, a conductive material such as carbon may be added for the purpose of improving the power receiving property of the negative electrode.

When carbon is contained in the negative electrode plate of a lead storage battery, depending on the amount of addition, carbon is discharged together with the gas from the surface of the negative electrode plate, especially from the surface crack, when hydrogen gas is generated during charging during battery case formation, and a separator in contact with this Easy to flow out to the surface. In particular, when the electrode plate group is pressed for the purpose of suppressing the softening of the positive electrode plate, the distance between the positive electrode plate and the negative electrode plate is reduced, and the carbon that has flowed out to the separator surface further penetrates into the separator and causes an internal short circuit. There was a case.

As a countermeasure, a separator for sealed lead-acid batteries (Patent Document 1) or a granular silica-type sealed battery, characterized in that glass fiber, silica powder, and silica sol are mixed into a separator mainly composed of glass fibers. In US Pat. No. 6,053,836, a carbon material having 0.5 to 5.0 mass% of the amount of the negative electrode active material added to the negative electrode active material has been proposed.

JP-A-7-29560 JP-A-6-283176

However, when the separator described in Patent Document 1 is used, the separator becomes hard due to the presence of a large amount of silica in the glass fiber, which makes it difficult to handle during stacking of electrode plates, or the amount of electrolytic solution retained. There are problems, such as fewer. In addition, it is conceivable to increase the thickness of the separator. However, if the thickness is significantly increased in a limited volume battery case, the number of electrode plates is reduced, resulting in insufficient capacity. Even if it can be made slightly thicker, the effect is insufficient. Furthermore, when a relatively hard separator having excellent short circuit resistance is used, there is a problem that cycle performance is not good.
Moreover, although the method of patent document 2 shows improvement in charge acceptability, when the formation at the time of producing a lead storage battery is performed by battery case formation, the carbon added by the generated hydrogen gas is a negative electrode. It leaves the plate and flows out into the electrolyte solution and floats upward. As a result, a large amount of carbon collects in the upper part and enters the separator and eventually causes a short circuit.

Accordingly, an object of the present invention is to provide a control valve type lead-acid battery having good formation efficiency without short-circuiting due to outflow of carbon even when a negative electrode is formed by laminating electrode plates containing carbon on the negative electrode at high pressure. It is what.

In order to solve the above-mentioned problems, the present invention provides a positive electrode plate in which a lattice substrate made of lead or a lead alloy is filled with a paste-like active material, and a paste-like active material containing carbon in a lattice substrate made of lead or a lead alloy. An electrode plate group formed by laminating a negative electrode plate filled with glass via a retainer mat mainly composed of glass fibers is housed in a battery case at a group pressure of 40 to 100 kPa, and after covering the lid, dilute sulfuric acid In the control valve type lead-acid storage battery that is formed by injecting the electrolyte and forming the battery case, and then replenishing and replenishing the battery.
1) The amount of the dilute sulfuric acid electrolyte solution after the lid is sealed is 95 to 105% of the electrode plate group height excluding the electrode plate ears.
2) The charging current from when the charge amount with respect to the theoretical capacity of the negative electrode active material reaches 100% until the charge amount with respect to the theoretical capacity of the positive electrode active material reaches 100% is 4.5 mA with respect to the total surface area of the positive electrode plate. / Cm ² or less,
3) Then charge it,
4) The present invention provides a control valve type lead-acid battery manufacturing method characterized in that the replacement fluid and the auxiliary charge are performed.

Here, it is preferable that the group pressure when the electrode plate group is accommodated in the battery case is in a high pressure state of 40 to 100 kPa. This is because if the group pressure when the electrode plate group is stored in the battery case is less than 40 kPa, the effect of suppressing the softening of the positive electrode active material is weak, and conversely if it exceeds 100 kPa, the group of electrode plate groups is inserted into the battery case. This is because the distance between the positive and negative electrode plates becomes short and short-circuiting easily occurs.
In addition, high pressure in this application is accommodating an electrode group in a battery case with the group pressure of 40 kPa or more.

Further, the optimization of the initial liquid injection amount of 1) will be described in detail below. If the height of the surplus liquid surface after the first injection is higher than 105% of the height of the electrode plate group excluding the ears of the electrode plate group, the entire electrode plate group is immersed in the liquid until immediately before the end of the battery case formation. In addition, the negative electrode absorption of oxygen gas generated from the positive electrode during charging is inhibited. For this reason, the negative electrode potential shifts to the hydrogen generation potential, the hydrogen gas generation section during the formation of the battery case becomes longer, and carbon may easily flow out. On the other hand, if the height of the liquid level is lower than 95%, an unformed part remains at the upper part of the electrode plate, resulting in poor conversion efficiency.

Next, the reduction of the charging current in the vicinity of the hydrogen gas generation potential of 2) will be described in detail below. During the formation of the battery case, the negative electrode potential starts to rise from around 90% of the charge amount relative to the theoretical capacity of the negative electrode active material, and when the charge amount reaches 100%, hydrogen gas starts to be generated (the mercuric sulfate electrode is used as the reference electrode). The hydrogen generation potential is around -1.5V). In a preliminary experiment, several places were extracted at a predetermined charge amount with respect to the theoretical capacity of the negative electrode active material and disassembled, and the charge amount from 100% to the charge amount with respect to the theoretical capacity of the positive electrode active material reached 100%. As a result of the optimization of the charging current in this section, it was found that carbon outflow could be suppressed at 4.5 mA / cm ² or less with respect to the total surface area of the positive electrode plate. If the current is larger than this current, the outflow of carbon cannot be suppressed, and the lower the current, the better. However, if it is too low, the charging time becomes longer and the production efficiency becomes worse. There is a need. Accordingly, the charging current is preferably 2.6 to 4.5 mA / cm ² .
The total surface area of the positive electrode plate in the present invention is defined as the surface area of the front and back surfaces of the positive electrode plate excluding the ears and feet of the positive electrode plate and the circumferential side surfaces (upper and lower left and right) of the positive electrode plate x the number of positive electrode plates. It is.

As described above, in the present invention, in the latter half of the battery formation, that is, before reaching the hydrogen generation potential, the negative electrode absorption of the oxygen gas generated from the positive electrode due to the exposure of the negative electrode plate surface due to liquid reduction is promoted, and the hydrogen generation potential is exceeded. By lowering, carbon outflow associated with the generation of hydrogen gas is prevented, and carbon outflow is suppressed throughout the entire chemical conversion.

The manufacturing method of the control valve type lead acid battery of this invention can prevent the internal short circuit by the carbon outflow at the time of battery case formation, and can provide the manufacturing method of the control valve type lead acid battery with favorable formation efficiency.

In the present invention, a positive electrode plate and a negative electrode plate are produced by a conventional method, carbon is added to the negative electrode plate, and the positive electrode plate and the negative electrode plate are alternately laminated via a retainer mat formed by making glass fibers. Configure the plate group, incorporate the electrode plate group into the battery case at the desired group pressure, strap weld the same polarity ear group by the usual method and simultaneously form the positive and negative terminals, weld the battery case and the lid, and then Then, the battery is formed with the charging current, and then the shortage with respect to the target liquid amount and the insufficient amount of electrolyte due to the liquid reduction are replenished and supplemented to produce a control valve type lead storage battery.
By using the control valve type lead-acid battery manufacturing method according to the present invention, in the first half of the battery case formation, the outflow of carbon is suppressed by weakening the hydrogen gas generation rate even under the hydrogen generation potential, and the second half of the battery case formation. Then, by absorbing the negative electrode of oxygen gas generated from the positive electrode due to exposure of the negative electrode plate surface due to liquid reduction and lowering it from the hydrogen generation potential, carbon outflow associated with hydrogen gas generation is prevented, and carbon outflow is performed throughout the entire chemical conversion. It is possible to suppress.

This control valve type lead acid battery was produced as follows. First, an unformed positive electrode plate obtained by filling a grid substrate mainly composed of lead with a positive electrode active material paste prepared by a conventional method, and carbon in the lattice substrate mainly composed of lead with respect to the amount of the negative electrode active material An unformed negative electrode plate added with 1% by mass was aged and dried to prepare positive and negative electrode plates, respectively. Then, these positive and negative plates are alternately laminated via a retainer mat formed by mainly making glass fibers to form an electrode plate group of 8 positive plates / 9 negative plates, and then the plate The group was assembled in a battery case under high pressure of 40 kPa. Next, the same polarity ear group was strap-welded by a conventional method, and at the same time, positive and negative electrode terminals were formed. Next, after the battery case and the lid are welded, a predetermined amount of dilute sulfuric acid electrolyte is injected so that the liquid surface height is 95% of the height of the electrode plate group excluding the electrode tab, and the theory of the negative electrode active material The charging current is applied at 5.3 mA / cm ² with respect to the total surface area of the positive electrode plate until the charge amount with respect to the capacity reaches 100%, and the charge amount with respect to the theoretical capacity of the negative electrode active material reaches 100%. The charging current is applied to the total surface area of the positive electrode plate until the amount of charge with respect to the theoretical capacity reaches 100% at 4.27 mA / cm ² , and then the amount of charge with respect to the theoretical capacity of the positive electrode active material reaches 200%. Energize with a current of 5.3 mA / cm ² with respect to the total surface area of the positive electrode plate, and then replenish the shortage with respect to the target liquid amount and the insufficient amount of electrolyte due to liquid reduction, and the charge amount with respect to the theoretical capacity of the positive electrode active material A supplemental charge is made so that becomes 1%, and 2V To prepare a control valve type lead-acid battery 200 Ah (Example 1).
In the same manner as described above, as shown in Table 1, the liquid level is 95 to 105% of the plate group height excluding the electrode tab, and the current density is 100% of the charge amount with respect to the theoretical capacity of the negative electrode active material. The charging current is 4.5 mA / cm ² or less with respect to the area of the negative electrode plate until the amount of charge with respect to the theoretical capacity of the positive electrode active material reaches 100%, and the group pressure when the electrode plate group is incorporated into the battery case Various 2V-200 Ah control valve type lead-acid batteries were prepared so as to be in a high pressure state of 40 to 100 kPa (Examples 2 to 9).

(Comparative Example 1)
As shown in Table 1, the liquid level is 90 to 110% of the height of the electrode plate group excluding the electrode plate ear, the current density is 4.76 mA / cm ² or less with respect to the total surface area of the positive electrode plate, and the electrode plate group is electrically charged. The group pressure at the time of incorporating in the tank is 20 to 120 kPa, the liquid level height, the amount of charge with respect to the theoretical capacity of the negative electrode active material reaches 100%, and the amount of charge with respect to the theoretical capacity of the positive electrode active material reaches 100%. 2V-200 Ah control valve type lead-acid battery as in Example 1 except that at least one item of current density and group pressure with respect to the total surface area of the positive electrode is changed outside the specified value of the present invention. (Comparative Examples 1 to 11).

Of the various control valve lead-acid batteries produced above, the electrolyte level reaches 100% of the electrode plate group height, and the charge amount with respect to the theoretical capacity of the negative electrode active material reaches 100%. Control valve-type lead acid batteries (Examples 7 to 9, Comparative Example 10) in which the charging current until the amount of charge with respect to the theoretical capacity of the active material reaches 100% is 4.5 mA / cm ² with respect to the total surface area of the positive electrode plate. 11) and the amount of charge with respect to the theoretical capacity of the positive electrode active material is 100% after the liquid surface height of the electrolyte reaches 100% of the electrode plate group height and the amount of charge with respect to the theoretical capacity of the negative electrode active material reaches 100%. For the control valve type lead storage battery in which the charging current until reaching% is 4.27 mA / cm ² (Example 2) and 4.76 mA / cm ² (Comparative Example 7) with respect to the total surface area of the positive electrode plate, Make two of each, one of which is fixed at 25 ° C. After putting into the tank and discharging for 2 hours at a discharge current of 0.25 CA (DOD 50%), charging is performed 90% at 0.25 CA, further charging is 15% at 0.15 CA, and the charge amount is 105% in total. The following cycle test was conducted. In the cycle test, a capacity test was performed every 100 cycles, and the time when 70% of the rated capacity was cut was regarded as the life.
In the capacity test, discharging was performed at a current of 0.1 CA and a final voltage of 1.8 V in a 25 ° C. environment, and charging was performed at 90% at a current of 0.1 CA and then at 30% at 0.05 CA (120% in total with respect to the rated capacity). Charging).

The evaluation results of Examples 1 to 9 and Comparative Examples 1 to 11 are shown in Table 1. Table 1 shows the electrolyte level, current density, group pressure when inserting the electrode plate group, presence or absence of carbon outflow, short circuit condition, condition of electrode plate formation, number of cycles, and comprehensive judgment results. did.
In addition, the presence or absence of carbon outflow was evaluated on the basis of the carbon outflow level after chemical conversion based on a five-stage evaluation by observing the cross section of the separator, and the extent of carbon outflow from the negative electrode to the positive electrode with respect to the thickness direction of the separator was judged. 1 is carbon outflow stays within 20% or less of the separator thickness, 2 is 20% or more and less than 40%, 3 is 40% or more and less than 60%, 4 is 60% or more and less than 80% In this case, 5 has 80% or more of carbon movement or a short circuit due to penetration to the positive electrode plate. The carbon flowed out by visual observation of the entire electrode plate group and the upper part of the end plate.
In addition, the column which described the arrow in a table | surface shows that it is the same as the number described in the column immediately above which the arrow points.

As shown in Table 1, in Examples 1 to 9 according to the present invention, although some carbon outflow is observed, internal short-circuiting does not occur, and the electrode plates located at both ends of the electrode plate group The chemical formation was also good.
On the other hand, in Comparative Examples 1 to 11 in which at least one item of the liquid level height, current density, and group pressure is outside the specified values of the present invention, the carbon outflow level is as large as 3 to 5, and of these, the carbon outflow In the case of level 5, internal short circuit occurs (Comparative Examples 8 and 9), or even if the carbon outflow level is small, the formation of the electrode plates positioned at both end plates of the electrode plate group is poor (Comparative Examples 1 and 3). ).
The liquid level is 100% of the plate group height excluding electrode plate ears, the current density is 4.50 mA / cm ² , and the group pressure when incorporating the plate group into the battery case is 20 to 120 kPa. In Example 5 and Examples 7 to 9 and Comparative Examples 10 to 11 respectively changed, Example 5 and Examples 7 to 9 having a group pressure of 40 to 100 kPa are excellent in cycle life. The comparative example 10 which set 20 kPa and the comparative example 11 which made the group pressure 120 kPa were a low value compared with Example 5 and Examples 7-9. The former has a low group pressure, so the effect of suppressing the softening of the positive electrode active material is low. The latter has a short distance between the positive and negative electrodes, and a short circuit due to carbon outflow causes the early capacity decrease.
Further, the liquid level is 100% of the height of the electrode plate group excluding the electrode plate ear, the group pressure when the electrode plate group is incorporated into the battery case is 40 kPa, and the current density is 4.27 to 4.76 mA / cm ^2. In Examples 2 and 5 and Comparative Example 7 respectively changed, it was confirmed that the cycle life characteristics improved as the current density decreased.
In this example, the amount of carbon added to the negative electrode plate was 1.0% by mass, but the amount of carbon added was 0.2 to 2.0% by mass in the same manner as in Example 1 and Comparative Example 1. The same effect was also obtained in the case of.

As described above, the amount of the diluted sulfuric acid electrolyte solution after the lid is sealed is 95 to 105% of the plate group height excluding the electrode plate ears, and the liquid surface height is 95 to 105% of the theoretical capacity of the negative electrode active material. The charging current from when the amount of charge reaches 100% until the amount of charge with respect to the theoretical capacity of the positive electrode active material reaches 100% is set to 4.5 mA / cm ² or less with respect to the total surface area of the positive electrode plate. By performing replenishment and replenishment, before reaching the hydrogen generation potential, hydrogen gas is absorbed by promoting negative electrode absorption of oxygen gas generated from the positive electrode due to exposure of the negative electrode plate surface due to liquid reduction and lowering the hydrogen generation potential. It is possible to prevent the outflow of carbon accompanying the generation of carbon and suppress the outflow of carbon throughout the entire chemical conversion.

Claims (1)

A positive electrode plate obtained by filling a lattice substrate made of lead or a lead alloy with a paste-like active material, and a negative electrode plate made by filling a lattice substrate made of lead or a lead alloy with a paste-like active material containing carbon. The electrode plate group formed by laminating through the retainer mat mainly is stored in the battery case at a group pressure of 40 to 100 kPa, and after covering the lid, dilute sulfuric acid electrolyte is injected to form the battery case. In the control valve type lead acid battery,
1) The amount of the dilute sulfuric acid electrolyte solution after the lid is sealed is 95 to 105% of the electrode plate group height excluding the electrode plate ears.
2) The charging current from when the charge amount with respect to the theoretical capacity of the negative electrode active material reaches 100% until the charge amount with respect to the theoretical capacity of the positive electrode active material reaches 100% is 4.5 mA with respect to the total surface area of the positive electrode plate. / Cm ² or less,
3) Then charge it,
4) A method for producing a control valve type lead storage battery, characterized in that the solution is replenished and charged.