JP4679690B2 - Nickel metal hydride storage battery manufacturing method and nickel metal hydride storage battery manufacturing apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method and apparatus for manufacturing a nickel metal hydride storage battery using a hydrogen storage alloy.
[0002]
[Prior art]
In recent years, alkaline storage batteries have attracted attention as power sources for portable devices, portable devices, and the like, and as mobile power sources for electric vehicles, hybrid electric vehicles, and the like, and higher performance is required than ever. In particular, a nickel-hydrogen storage battery is a secondary battery having a positive electrode made of an active material mainly composed of nickel hydroxide and a negative electrode mainly made of a hydrogen storage alloy, and has a high energy density and excellent reliability. It is rapidly spreading as a secondary battery.
[0003]
The nickel-metal hydride secondary battery has a problem that the initial discharge capacity is small because the activity of the hydrogen storage alloy is low immediately after battery assembly. In order to solve this problem, a manufacturing method is generally used in which the hydrogen storage alloy is activated by charging and discharging the battery after the battery is assembled.
[0004]
Further, in the nickel hydride storage battery, when the internal pressure of the battery rises, a safety valve is formed in the battery case in order to prevent the internal gas from escaping and the internal pressure from becoming excessive.
[0005]
[Problems to be solved by the invention]
However, the conventional manufacturing method has a problem that the charge / discharge rate cannot be increased in the charge / discharge process for activating the hydrogen storage alloy, and charge / discharge takes time. This is because if the hydrogen storage alloy is not fully activated and charging / discharging at a high current value, the internal pressure becomes higher than the set value of the safety valve, the safety valve opens, and part of the electrolyte is in the battery. This is because it is discharged together with the gas. Therefore, the conventional manufacturing method has a problem that productivity and manufacturing cost are not sufficiently reduced.
[0006]
In order to solve the above-described problems, an object of the present invention is to provide a nickel-metal hydride storage battery manufacturing method and a manufacturing apparatus that can manufacture nickel-metal hydride storage batteries with high productivity and low cost.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, a method for producing a nickel metal hydride storage battery of the present invention includes a positive electrode containing nickel hydroxide, a negative electrode containing a hydrogen storage alloy, and a case provided with a safety valve that opens at an internal pressure equal to or higher than a set value. A method for manufacturing a nickel metal hydride storage battery, wherein a first step of assembling a battery by enclosing a positive electrode, a negative electrode, a separator and an electrolyte in a case, and a current for opening the battery at the set value of the safety valve while pressurizing the safety valve And a second step of charging / discharging with a value . In the manufacturing method of the present invention, since charging and discharging can be performed at a high current value in the second step, a nickel-metal hydride storage battery can be manufactured with high productivity and at low cost.
[0008]
In the said manufacturing method, it is preferable to pressurize a safety valve using air in a 2nd process. According to the above configuration, the safety valve can be pressurized easily and inexpensively.
[0009]
In the said manufacturing method, it is preferable to charge / discharge in the 2nd process, cooling a battery with a refrigerant | coolant. According to the said structure, charging / discharging can be performed with a high electric current value.
[0010]
The nickel hydride storage battery manufacturing apparatus of the present invention is a nickel hydride storage battery manufacturing apparatus including a positive electrode containing nickel hydroxide, a negative electrode containing a hydrogen storage alloy, and a case having a safety valve that opens at an internal pressure equal to or higher than a set value. A pressing jig having a recess, a pressing means for pressing the pressing jig against the case so as to store the safety valve in the recess, and a pressure for supplying air into the recess to pressurize the safety valve. and means, further, the set value of the battery the safety valve and said Rukoto comprises a charging and discharging means for charging and discharging at a current value of the valve opening. According to the manufacturing apparatus of the present invention, since charging and discharging can be performed with a high current value, a nickel-metal hydride storage battery can be manufactured with high productivity and low cost.
[0011]
The manufacturing apparatus of the present invention preferably further includes a fixing means for fixing the pressing jig in a state where the pressing jig is pressed against the case and the inside of the recess is airtight. According to the above configuration, the pressing jig can be easily pressed at a substantially constant pressure. In addition, since the battery can be moved while the holding jig is pressed against the case, it is easy to perform processes such as charging and discharging.
[0012]
Above manufacturing apparatus of the present invention, in order to perform the activation of the battery, comprising a charging and discharging means for charging and discharging the battery.
[0013]
In the manufacturing apparatus of the present invention, it is preferable to further include a cooling means for cooling the battery in order to activate the battery.
[0014]
In the manufacturing apparatus of the present invention, it is preferable that the pressurizing means includes a pipe connected to the recess and an air coupler connected to the pipe. According to the said structure, the pressurization to a recessed part can be performed easily. In addition, the battery can be freely moved while being pressed into the recess.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below.
[0016]
(Embodiment 1)
Embodiment 1 demonstrates the manufacturing method of the nickel hydride storage battery of this invention.
[0017]
In the method for producing a nickel-metal hydride storage battery of the present invention, first, a positive electrode, a negative electrode, a separator, and an electrolytic solution are sealed in a case to assemble a battery (first step). In the first step, as the positive electrode, the negative electrode, the separator, the electrolytic solution, and the case, those generally used for nickel metal hydride storage batteries can be used. Specifically, for example, foamed nickel filled with an active material mainly composed of nickel hydroxide can be used as the positive electrode. As the negative electrode, for example, a hydrogen storage alloy containing Mm (Misch metal), nickel, aluminum, cobalt, and manganese can be used. As the separator, for example, a sulfonated polypropylene separator can be used. As the electrolytic solution, an alkaline aqueous solution mainly composed of potassium hydroxide can be used. The case also includes a safety valve that opens at an internal pressure equal to or higher than a set value . When the internal pressure in the case becomes higher than the threshold value, the safety valve releases the internal gas until the internal pressure in the case becomes equal to or lower than the threshold value. The same applies to a module battery in which a plurality of unit cells are combined.
[0018]
Thereafter, the battery assembled in the first step is charged and discharged with a current value that opens at the set value of the safety valve while pressurizing the safety valve of the case (second step). The charging / discharging is performed to activate the active material of the assembled battery. In the second step, it is preferable to pressurize the safety valve using air. In the second step, it is preferable to charge and discharge the battery while cooling it with a refrigerant.
[0019]
In the manufacturing method of the nickel hydride storage battery of the present invention, charging and discharging are performed while pressurizing the safety valve in the second step. For this reason, the operating pressure of the safety valve increases by the increased amount. For this reason, in the said manufacturing method, even if the hydrogen storage alloy is not fully activated, charging / discharging can be performed with a high electric current value, and activation can be performed in a short time. Therefore, according to the said manufacturing method, a nickel hydride storage battery can be manufactured cheaply with high productivity.
[0020]
(Embodiment 2)
Embodiment 2 demonstrates the manufacturing apparatus of the nickel-metal hydride storage battery of this invention.
[0021]
An apparatus for producing a nickel metal hydride storage battery according to the present invention is an apparatus for producing a nickel metal hydride storage battery including a positive electrode containing nickel hydroxide, a negative electrode containing a hydrogen storage alloy, and a case having a safety valve that opens at an internal pressure equal to or higher than a set value. A pressing jig provided with a recess, a pressing means for pressing the pressing jig against the case so as to store the safety valve in the recess, and air is supplied into the recess to pressurize the safety valve. and a pressure means for further, in the set value of the battery the safety valve and said Rukoto comprises a charging and discharging means for charging and discharging at a current value of the valve opening.
[0022]
According to the manufacturing apparatus of the second embodiment, a nickel-metal hydride storage battery can be manufactured with high productivity and low cost.
[0023]
【Example】
Hereinafter, the present invention will be described in more detail with reference to examples.
[0024]
First, the nickel metal hydride storage battery manufactured in this example will be described. In Example 1, a module battery 10 in which a plurality of single cells (nickel metal hydride storage batteries) were connected was produced.
[0025]
A top view and a side view of the module battery 10 are schematically shown in FIGS. 1A and 1B, respectively. Also, a vertical sectional view of the module battery 10 is schematically shown in FIG.
[0026]
Referring to FIG. 1, the module battery 10 includes a case 30 including an integrated battery case 11 and a lid 20. A positive electrode terminal 12 and a negative electrode terminal 13 are formed on the side surface of the integrated battery case 11. The lid 20 is formed with a safety valve 21 and a sensor mounting hole 22 for mounting a sensor for detecting the internal temperature. In addition, although the integrated battery case 11 and the lid | cover 20 equip the surface with the unevenness | corrugation for improving the heat dissipation in use, illustration is abbreviate | omitted in FIG. 1 and FIG.
[0027]
The integrated battery case 11 is made of polypropylene and includes a partition 11a formed inside. That is, the integrated battery case 11 is divided into a plurality of battery cases 11b by the partition 11a. In each battery case 11b, an electrode plate group 14 and an electrolyte (not shown) are sealed.
[0028]
The partition 11a includes an opening on the upper side. A current collector 15 (hatching is omitted) of the electrode plate group 14 accommodated in each battery case 11b and a current collector 16 (hatching is omitted) of the adjacent electrode plate group 14 are connected fittings 17 arranged in the opening. Are electrically connected. The connection fittings 17 located at both ends are connected to the positive terminal 12 and the negative terminal 13.
[0029]
The safety valve 21 is a valve for discharging the internal gas until the internal pressure becomes equal to or lower than the threshold when the internal pressure in the integrated battery case 11 becomes equal to or higher than the threshold. In this embodiment, the safety valve 21 that opens when the internal pressure of the module battery 10 becomes 0.5 MPa or more is used. The lid 20 is formed with a through hole (not shown) for connecting the adjacent battery cases 11b, and the internal pressure of each battery case 11b is substantially equal.
[0030]
A cross-sectional view in the horizontal direction of the electrode plate group 14 is schematically shown in FIG. Referring to FIG. 3, electrode group 14 includes positive electrodes 31 and negative electrodes 32, bag-shaped separators 33, and current collectors 15 and 16 that are alternately arranged. The positive electrode 31 is inserted into a bag-like separator 33 (hatching is omitted). The positive electrode 31 is welded to the current collector 15, and the negative electrode 32 is welded to the current collector 16. Further, an outer peripheral separator 34 (hatching is omitted) is disposed on the side surface of the electrode plate group 14.
[0031]
As described above, the module battery 10 is a battery in which six cells including the electrode plate group 14 are connected in series.
[0032]
Below, the manufacturing method of the module battery 10 is demonstrated.
[0033]
The positive electrode 31 was produced by filling foamed nickel with a positive electrode active material paste, followed by drying, rolling, and cutting. As the positive electrode active material, nickel hydroxide to which cobalt oxide was added was used. The negative electrode 32 was prepared by applying a negative electrode paste to a punching metal made of nickel, followed by drying, rolling, and cutting. A hydrogen storage alloy was used for the negative electrode. For the separator 33, a sulfonated polypropylene was used. Moreover, the electrolyte solution which has potassium hydroxide as a main component was used for electrolyte solution.
[0034]
The positive electrode 31 was inserted into a bag-shaped separator 33, and the positive electrode 31 and the negative electrode 32 were alternately stacked. The positive electrode group 14 was formed by welding the positive electrode 31 to the current collector 15 and welding the negative electrode 32 to the current collector 16. The electrode plate group 14 was inserted into each battery case 11b, and the adjacent electrode plate groups 14 were connected in series by a connection fitting 17. Thereafter, the electrolytic solution was injected, and the integrated battery case 11 was sealed with the lid 20. In this way, a module battery 10 having a rated capacity of 6.5 Ah was assembled.
[0035]
The module battery 10 was initially charged / discharged. Specifically, charging is first performed at a current equivalent to 0.1 C (1 C = 6.5 A) until the SOC (State Of Charge (charge state), which is the ratio of the charged amount to the rated capacity) becomes 130%. After that, the battery was discharged at a current corresponding to 4C until the SOC reached 0%. By this initial charge / discharge, Co and Co (OH) ₂ contained in the positive electrode 31 were oxidized to CoOOH.
[0036]
Thereafter, as shown in FIG. 4, the module battery 10 that had been initially charged and discharged was mounted on an aluminum cooling jig 41. The cooling jig 41 has a U-shape, and has a through hole 41a on its side. The side upper surface 41 b of the cooling jig 41 was formed at a position so as not to touch the positive electrode terminal 12 and the negative electrode terminal 13. Since the cooling jig 41 is U-shaped, the module battery 10 can be easily attached and detached. The cooling jig 41 preferably has a concavo-convex shape that fits with the concavo-convex shape on the surface of the module battery 10 on the surface that contacts the module battery 10.
[0037]
Then, as shown in FIG. 5, the some cooling jig 41 with which the module battery 10 was mounted | worn was connected. At this time, the bolt 51 was easily passed through the through hole 41a provided in the side portion of the cooling jig 41 and could be fixed easily. Each module battery 10 was arranged so that the direction was opposite to that of the adjacent module battery 10. Further, an end plate 52 is disposed at one end of the connected cooling jig 41 to restrain the whole.
[0038]
Thereafter, a pressing jig 61 was set on each safety valve 21 of the connected module battery 10. The process of setting the module battery 10 on the pressing jig 61 is schematically shown in FIG. As shown in FIG. 6, after setting the holding jig 64 on the safety valve 21, the wedge 63 is inserted into the hole 71 located at a fixed height of the fixed block 62 fixed to the pedestal 70, thereby pressing with a constant pressure. The pressing jig 64 for storing the safety valve 21 can be brought into close contact with the spring 68 by pressing the jig 61.
[0039]
FIG. 7 schematically shows a plan view of the structure of the pipe connected to the pressing jig 61 when viewed from the module battery 10 side. With reference to FIG. 7, the pressing jig 61 is connected to the pressing jig 64 and the pressing jig 64 disposed at a position corresponding to the safety valve 21 of the module battery 10 mounted on the cooling jig 41. A pipe 65 and an air coupler 66 connected to the tip of the pipe 65 are provided. The structure of the holding jig 64 is schematically shown in FIG. The holding jig 64 is movably connected to the support column 67 and is pressed against the case 30 side of the module battery 10 by a spring 68. The holding jig 64 includes a recess 64a in which the safety valve 21 is inserted and a holding rubber 64b. When the pressing jig 61 is pressed by the module battery 10, the pressing rubber 64 b comes into close contact with the periphery of the safety valve 21 and is in an airtight state. The recess 64 a is connected to the pipe 65. That is, the safety valve 21 can be pressurized by injecting compressed air from the air coupler 66. Further, after the pressing jig 61 is fixed to the module battery 10 using the fixing block 62 and the wedge 63, the compressed air is injected from the air coupler 66 and the air coupler 66 is closed, so that the safety valve 21 remains pressurized. The module battery 10 connected in a state can be moved. Therefore, by using the jig, it becomes easy to activate the safety valve 21 in a pressurized state.
[0040]
As described above, the nickel-metal hydride storage battery manufacturing apparatus according to the present embodiment includes a pressing jig 64 having a recess 64a and pressing means (spring) that presses the pressing jig 64 toward the case 30 so as to store the safety valve 21. 68) and pressurizing means (such as a pump (not shown)) for supplying air into the recess 64a and pressurizing the safety valve 21. Further, the nickel-metal hydride storage battery manufacturing apparatus of the present embodiment has a fixing means (fixing block 62) for fixing the pressing jig 64 in a state where the pressing jig 64 is pressed by the case 30 and the inside of the recess 64a is airtight. And a wedge 63). Moreover, the manufacturing apparatus of the nickel metal hydride storage battery according to the present embodiment may further include charge / discharge means for charging / discharging the battery. Moreover, the manufacturing apparatus of the nickel hydride storage battery of a present Example is provided with the cooling means (cooling jig 41) for cooling a battery. In the nickel-metal hydride battery manufacturing apparatus of this embodiment, the pressurizing means includes a pipe 65 connected to the recess 64 a and an air coupler 66 connected to the pipe 65.
[0041]
In this embodiment, a pressure of 0.5 MPa was applied to the safety valve 21 by injecting 0.5 MPa of compressed air from the air coupler 66. In this case, the safety valve 21 does not operate until the internal pressure in the module battery 10 reaches the same level (about 1.0 MPa) as the sum of the operating pressure of the safety valve 21 and 0.5 MPa. . Thereafter, the air coupler 66 was disconnected from the compressed air supply device (not shown) to make the inside of the pipe 65 airtight.
[0042]
Thereafter, the connected cooling jig 41 was placed in a water tank, and the cooling jig 41 and the module battery 10 were cooled by running water (refrigerant). At this time, the flowing water was controlled to a height that does not contact the positive terminal 12 and the negative terminal 13 of the module battery 10 and to cover the side upper surface 41 b of the cooling jig 41.
[0043]
Then, the charging / discharging cycle was repeated 20 times while charging with a current corresponding to 4C until the SOC reached 90% with flowing water flowing, and discharging until the SOC became 0% with a current corresponding to 4C. At this time, the internal temperature of the module battery 10 measured by the sensor mounted in the sensor mounting hole 22 increased to 50 ° C.
[0044]
In this way, the activation of the module battery 10 was completed. At this time, the electrolyte solution was not discharged by opening the safety valve. The total time required for activation by the above method was 12 hours. On the other hand, in the case of the conventional manufacturing method, when charging / discharging was performed at a current of 4 C, the internal pressure of the module battery 10 became larger than 0.5 MPa, the safety valve was opened, and the electrolyte was discharged. Therefore, in the case of the conventional manufacturing method, it is necessary to activate at a low current, and when charging / discharging at 1 C, it took 48 hours to activate.
[0045]
Thus, by using the manufacturing method and manufacturing apparatus of the present invention, a nickel-metal hydride storage battery could be manufactured with good productivity and low cost.
[0046]
Although the embodiments of the present invention have been described above by way of examples, the present invention is not limited to the above-described embodiments, and can be applied to other embodiments based on the technical idea of the present invention.
[0047]
For example, the manufacturing method of the present invention is not limited to the method for manufacturing the battery described in the above embodiment.
[0048]
【The invention's effect】
As described above, according to the manufacturing method and manufacturing apparatus of the nickel-metal hydride storage battery of the present invention, the battery can be activated in a short time, and therefore, the nickel-metal hydride storage battery can be manufactured inexpensively with high productivity.
[Brief description of the drawings]
FIG. 1A is a top view and FIG. 1B is a side view showing an example of a nickel-metal hydride storage battery manufactured with the nickel-metal hydride storage battery of the present invention.
2 is a vertical sectional view of the nickel-metal hydride storage battery shown in FIG. 1. FIG.
3 is a horizontal cross-sectional view of the electrode plate group of the nickel-metal hydride storage battery shown in FIG. 1. FIG.
FIG. 4 is a perspective view showing an example of one step in the method for producing the nickel-metal hydride storage battery of the present invention.
FIG. 5 is a plan view showing an example of another step in the method for producing a nickel-metal hydride storage battery of the present invention.
FIG. 6 is a perspective view showing an example of another step in the method for manufacturing a nickel metal hydride storage battery of the present invention.
FIG. 7 is a plan view showing an example of a pipe structure of a pressing jig used in the method for manufacturing a nickel metal hydride storage battery of the present invention.
8 is a partially enlarged cross-sectional view of the pressing jig shown in FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Module battery 11 Integrated battery case 11b Battery case 14 Electrode board group 21 Safety valve 30 Case 31 Positive electrode 32 Negative electrode 33 Separator 41 Cooling jig 61 Pressing jig 62 Fixing block 63 Wedge 64 Holding jig 65 Piping 66 Air coupler 70 Base 71 Hole

Claims (7)

A method for producing a nickel-metal hydride storage battery, comprising: a positive electrode containing nickel hydroxide; a negative electrode containing a hydrogen storage alloy; and a case provided with a safety valve that opens at an internal pressure equal to or higher than a set value .
A first step of assembling a battery by enclosing the positive electrode, the negative electrode, a separator and an electrolyte in the case;
And a second step of charging and discharging the battery at a current value that opens at the set value of the safety valve while pressurizing the safety valve.   The method for producing a nickel-metal hydride storage battery according to claim 1, wherein in the second step, the safety valve is pressurized using air.   The manufacturing method of the nickel hydride storage battery of Claim 1 or 2 which charges / discharges, cooling the said battery with a refrigerant | coolant in a said 2nd process. A nickel-metal hydride battery manufacturing apparatus comprising a positive electrode containing nickel hydroxide, a negative electrode containing a hydrogen storage alloy, and a case having a safety valve that opens at an internal pressure equal to or higher than a set value ,
A holding jig with a recess,
A pressing means for pressing the pressing jig against the case so as to store the safety valve in the recess;
Pressurizing means for supplying air into the recess to pressurize the safety valve ;
Furthermore, the manufacturing apparatus of the nickel-metal hydride storage battery, characterized in Rukoto comprises a charging and discharging means for charging and discharging the battery at a current value which is opened at the set value of the safety valve.   The nickel-metal hydride storage battery manufacturing apparatus according to claim 4, further comprising a fixing means for fixing the pressing jig in a state where the pressing jig is pressed by the case and the inside of the concave portion is airtight. The apparatus for manufacturing a nickel-metal hydride storage battery according to claim 4 , further comprising a cooling means for cooling the battery. The nickel hydrogen storage battery manufacturing apparatus according to any one of claims 4 to 6 , wherein the pressurizing means includes a pipe connected to the recess and an air coupler connected to the pipe.

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