JP2005285378A - Alkali secondary battery and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an alkali secondary battery wherein plumping of an electrode plate is effectively suppressed in charging/discharging even having a low-rigid outer package, a cycle life property is hardly declined, and high quality can be maintained over a long period of time, and to provide its manufacturing method. <P>SOLUTION: An electrode body 14 has a structure in which a plurality of positive electrode plates 141 housed in bag-like separators 143 are arranged, and negative electrode plate 142 are sandwiched between them. Some areas of the positive electrode plates 141 and the negative electrode plates 142 are exposed from both end parts in X-direction respectively. The positive electrode current collector 15a and the negative electrode current collector 15b are joined to both ends of the electrode body 14. A restraining band 16 having an inner circumference size almost equivalent to its outer circumference size is fitted to a part of an outer peripheral surface of the electrode body 14. The restraining band 16 is set to cover a range of 20-90% of the surface area of the whole outer circumference of the electrode body 14. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an alkaline secondary battery and a method for manufacturing the same, and particularly to a technique for suppressing expansion of an electrode body.

  Alkaline secondary batteries are widely used as power sources for portable devices, power tools, vehicles, and the like. In particular, in recent years, an alkali having an advantage that energy density is significantly higher than that of a lead battery for a hybrid electric vehicle (HEV) and an electric vehicle (Pure-Electric Vehicle) that have been developed. Secondary batteries (hereinafter simply referred to as “batteries”) are used.

As a battery, there are a battery in which an electrode body having a winding structure is housed in an exterior body and a battery in which an electrode body having a laminated structure is housed. Among these, the electrode body having a laminated structure is superior in space efficiency as compared with that having a wound structure, and thus is used for applications in which high energy efficiency is required.
Some batteries have a structure in which a resin protective tape is attached to the outer periphery of the electrode body for the purpose of preventing foreign matter from entering the electrode body during manufacture (Patent Document 1).

By the way, as a battery for the HEV or the like, a battery having a resin exterior body has been developed. Thus, in a battery having a resin outer casing, the electrode plate is likely to swell during charging and discharging, and when the battery is used for a long period of time, the electrode plate is compared with the one having a metal outer casing. There is a problem that the cycle life characteristics are likely to be deteriorated due to the swelling of the steel.
On the other hand, even in the conventional battery, it is considered that the rib provided on the exterior body suppresses the expansion of the electrode plate, so that it is somewhat effective. However, the rib of the exterior body is provided in order to secure the refrigerant passage of the battery even when a plurality of batteries are arranged in parallel.
JP 2001-307760 A

However, the conventional battery cannot sufficiently suppress the expansion of the electrode plate. That is, even when a resin protective tape is wound around the outer periphery of the electrode body as in the battery of Patent Document 1, there is almost no effect of suppressing the expansion of the electrode plate, and the outer body is secured to secure the refrigerant passage. The provided ribs alone are not sufficient in suppressing the expansion of the electrode plate.
The present invention has been made to solve the above-mentioned problem, and even when a low-rigidity exterior body is provided, the expansion of the electrode plate is effectively suppressed, and the cycle life characteristics are hardly deteriorated. It is an object of the present invention to provide a battery capable of maintaining high quality over a wide range and a method for manufacturing the same.

In order to achieve the above object, the present invention has the following features. In addition, the “battery” used below indicates “alkaline secondary battery” as described above.
(1) A battery in which an electrode body in which a positive electrode plate and a negative electrode plate are sequentially stacked with a separator interposed therebetween is housed in an exterior body. And the other region is exposed inside the exterior body. This restraining member has alkali resistance, and its constituent material has a higher elongation rigidity than the material constituting the exterior body. It is characterized by having.

(2) In the battery according to (1), the restraining member fitted on the electrode body is an annular body covering a region of 20% to 90% with respect to the total surface area of the electrode body. Features.
(3) In the battery according to (1) or (2), the exterior body is made of a resin material, the restraining member is made of a metal material, and the electrode body is poled by the restraining member. In order not to cause a short circuit between the plates, the separator is interposed between at least one of the positive electrode plate and the negative electrode plate and the restraining member.

  (4) In the battery according to (3), the separator has a bag shape, and at least one of the positive electrode plate and the negative electrode plate is housed inside the separator and formed in a non-existing region of the restraining member. The electrode body is formed by alternately laminating each of the positive electrode plate and the negative electrode plate so that the end portion of each electrode plate protrudes. And a current collector plate is joined to an end portion of each electrode plate.

(5) The battery according to any one of (1) to (4), wherein the alkaline secondary battery has a sealed structure, that is, an alkaline sealed secondary battery. .
(6) The battery according to any one of (1) to (5), wherein a plurality of electrode bodies are accommodated in the exterior body, and the internal space of the exterior body corresponds to the number of electrode bodies accommodated. The electrode bodies are divided into a plurality of cell chambers, and each of the plurality of electrode bodies is stored separately for each cell chamber and is connected in series.

(7) A method for manufacturing a battery, having the following steps and features.
1) Electrode body forming step: A positive electrode plate and a negative electrode plate are laminated in order with a separator interposed therebetween to form an electrode body.
2) External fitting step: The annular restraining member is externally fitted to the electrode body from the direction intersecting with the stacking direction of the electrode bodies.

3) Current collector plate joining step: Two current collector plates are joined to both ends of the electrode member in the direction of external fitting of the restraining member.
4) Storage step: The electrode body after the current collector plate is joined is stored in the internal space of the case, and an electrolyte is injected into the internal space.

5) Sealing step: The lid is placed on the opening of the case and sealed by joining together.
And in the battery manufacturing method according to the present invention, the restraint member used in the external fitting step is made of an alkali-resistant material and has a higher elongation rigidity than the material constituting the case. Yes.

In the battery according to the present invention, a constraining member is externally fitted in a partial region on the outer periphery of the electrode body, and the constraining member has a higher elongation rigidity than the material constituting the exterior body. For this reason, in the battery according to the present invention, the expansion of the electrode plate is effectively suppressed by the restraining member, and the cycle life is hardly reduced.
In addition, if the purpose is only to suppress the expansion of the electrode plate, it is conceivable that the entire outer periphery of the electrode body is externally fitted with a restraining member. Since gas is generated and this gas needs to be circulated, it is necessary to expose a partial region of the electrode body. For this reason, in the battery of this invention, the area | region where the restraint member in the outer periphery of an electrode body is not externally fitted is in the state exposed inside the exterior body. Therefore, in the battery according to the present invention, gas can be circulated inside and outside the electrode body, and high battery performance is ensured.

Therefore, in the battery according to the present invention, even when an exterior body having low rigidity is provided, the expansion of the electrode plate is effectively suppressed, the cycle life characteristics are hardly deteriorated, and high quality can be maintained over a long period of time.
As described in (2) above, it is possible to expand the electrode plate by setting the restraining member so as to cover a region in the range of 20 (%) to 90 (%) with respect to the total surface area of the electrode body. It is desirable from both aspects of the suppression effect and the suppression effect of occurrence of short circuit caused by the restraining member.

Moreover, in the battery manufacturing method according to the present invention, an electrode body having a laminated structure is produced, and then a restraining member is externally fitted, and then a current collector plate is joined. By doing in this way, the restraint member which can suppress the expansion | swelling of an electrode plate reliably can be easily fitted on the outer periphery of an electrode body.
Therefore, in the method for producing a battery according to the present invention, even when a low-rigidity exterior body is provided, expansion of the electrode plate is effectively suppressed, the cycle life characteristics are hardly deteriorated, and high quality is maintained over a long period of time. Can be easily manufactured.

The best mode for carrying out the present invention will be described with a nickel-hydrogen (Ni-MH) sealed secondary battery (hereinafter simply referred to as “battery”) 1 as an example with reference to the drawings. Here, the battery 1 is for HEV, and is, for example, a battery with a voltage of 7.2 (V) and a nominal capacity of 6000 (mAh). The battery 1 described below is an example of the present invention, and the present invention is not limited thereto.
(Configuration of battery 1)
The configuration of the battery 1 will be described with reference to FIG. In addition, in FIG. 1, the battery 1 is shown by the expanded structure for convenience.

  As shown in FIG. 1, the battery 1 includes a case 10 and a lid 11 that constitute an exterior body, and six electrode body units 17 that are accommodated inside the case 10. Of these, the case 10 and the lid 11 are both made of a synthetic resin material, and form an exterior body by welding with the openings facing each other. A plurality of ribs 10 </ b> R extending in the Z direction are formed on a part of the outer surface of the case 10. The rib 10 </ b> R of the case 10 is formed integrally with the case 10, and a part of the outer surface of the case 10 is projected in a beam shape toward the outside. Here, the rib 10R is provided in order to secure a refrigerant passage between the plurality of batteries 1 even when the batteries 1 are arranged in parallel.

External connection terminals 13 a and 13 b are attached to both end surfaces of the case 10 in the X direction. In FIG. 1, for convenience, only the terminal 13a is shown out of the two external connection terminals 13a and 13b, and the illustration of the terminal 13b is omitted.
The internal space in the case 10 is divided into six cell chambers 102 by five partition walls 101. The partition wall 101 is formed up to the inner bottom surface of the case 10 so as to prevent the electrolyte solution from flowing between the cell chambers 102. Each of the partition walls 101 in the case 10 is formed with a through hole 101h upward in the Z direction.

The lid 11 is provided with five partition walls 111 corresponding to the partition walls 101 provided in the case 10. Each of the partition walls 111 of the lid 11 is formed with a notch 111a in a partial region, and the gas generated in each of the six cell chambers 102 flows through the notch 111a. It is possible.
In addition, a safety valve 12 is attached to the outside of the upper surface of the lid 11 for discharging the internal gas to the outside when the internal pressure reaches a specified value or more. The safety valve 12 is attached to each cell chamber 102 so as to allow gas to flow.

  The electrode body unit 17 includes an electrode body 14, positive and negative current collecting plates 15 a and 15 b that are joined to both ends of the electrode body 14 in the X direction, and a binding band that is externally fitted to a partial region on the outer periphery of the electrode body 14 16. These six electrode body units 17 are housed separately in each cell chamber 102 in the case 10, and the joint portions 15 p in the current collector plates 15 a and 15 b of the adjacent electrode body units 17 are welded through the through holes 101 h in the partition wall 101. Are joined in series. In addition, for the electrode body units 17 located at both ends in the X direction, the joint portions 15p of the respective one of the current collector plates 15a and 15b are joined to the external connection terminals 13a and 13b.

Although not shown in FIG. 1 and the like, a predetermined amount of electrolytic solution is injected into each cell chamber 102. The injection amount of the electrolytic solution is an amount sufficient for charging and discharging each electrode body unit 17 and is set to an amount that does not reach the notch portion 111a of the lid 11 only by tilting the battery 1 several times. Yes.
(Configuration of electrode body unit 17)
Next, the structure of the electrode body unit 17 which is the most characteristic part in the present embodiment among the respective parts constituting the battery 1 will be described with reference to FIG.

  As shown in FIGS. 2A and 2B, among the constituent elements of the electrode body unit 17, with respect to the electrode body 14, the positive electrode plate 141 and the negative electrode plate 142 are alternately stacked with the separator 143 interposed therebetween. It has the form which was made. Specifically, the positive electrode plate 141 is housed inside a bag-like separator 143, and the negative electrode plate 142 is sandwiched between each of the plurality of separators 143 containing the positive electrode plate 141. And from the both ends of the X direction in the electrode body 14, the partial area | region of the positive electrode plate 141 and the negative electrode plate 142 is in the state exposed, respectively. In addition, in the Y direction of FIG. 2A, the negative electrode plate 142 is disposed on both main surface portions of the electrode body 14.

A positive electrode current collector plate 15 a is joined to the end side of the positive electrode plate 141 in the electrode body 14, and a negative electrode current collector plate 15 b is joined to the end side of the negative electrode plate 142. As shown in the enlarged portion of FIG. 2A, each current collector plate 15a, 15b is formed with a joint portion 15p processed in a dimple shape in the upper portion in the Z direction.
In addition, a constraining band 16 having an inner peripheral size substantially the same as the outer peripheral size is externally fitted to a partial region of the outer periphery of the electrode body 14. The restraint band 16 is set to a size that covers a range of 20% to 90% with respect to the entire outer surface area of the electrode body 14. The restraint band 16 is made of a material having higher elongation rigidity than the synthetic resin that is a material constituting the case 10 and the lid 11 of FIG. As an example of such a material, Ni plating SPCD is used in the present embodiment. Here, SPCD indicates a cold rolled steel sheet.

As shown in FIG. 2B, the electrode body 14 and the restraining band 16 have a positional relationship in a state where there is almost no gap between the inner and outer peripheries thereof. As shown in the enlarged portion, the restraining band 16 and the negative electrode plate 142 are in contact with each other on both main surface portions of the electrode body 14, but the restraining band 16 and the positive electrode plate 141 are electrically connected by the separator 143. Insulation is ensured. When the positive electrode plate 141 is not housed inside the bag-shaped separator 143 as in the electrode body 14 according to the present embodiment, a strip-shaped separator is interposed between the electrode plates 141 and 142. Therefore, it is necessary to separately insert an insulating member between the electrode body and the restraining band 16.
(Superiority of battery 1)
The superiority of the battery 1 having the above structure will be described below.

  In the battery 1, a restraining band 16 is externally fitted to each electrode body unit 17 housed in each cell chamber 102 of the case 10. Since the constituent material of the restraining band 16 is made of Ni-plated SPCD having higher elongation rigidity than the constituent material of the case 10 and the lid 11, the case 10 made of a synthetic resin material and having low rigidity is used. In this case, the expansion of the electrode plates 141 and 142 during charging / discharging is reliably suppressed. That is, as shown in FIG. 2, the restraint band 16 is fitted to the outer periphery of the electrode body 14 with almost no gap, so that the electrode plates 141 and 142 constituting the electrode body 14 are expanded during charging and discharging. Can be suppressed.

  In a conventional battery that does not include the restraining band 16, the outer body is responsible for suppressing the expansion of the electrode plate during charging and discharging. However, as the development is progressing for HEV applications and the like, a resin material is used for the outer body. In the case of using, the rigidity of the exterior body becomes low, and it is difficult to effectively suppress the expansion of the electrode plate. In particular, when the thickness of the exterior body is reduced in order to reduce the weight or the size, it is difficult to suppress the expansion. Therefore, in such a conventional battery, the cycle life is shortened. Further, even if a protective tape (made of a resin material) is attached to the outer periphery of the electrode body as in the battery of Patent Document 1, the elongation rigidity is low and the electrode plate may have a function of suppressing the expansion of the electrode plate. Absent.

On the other hand, since the battery 1 according to the present embodiment has the restraining band 16 made of a material having higher rigidity than the case 10 as described above, it has excellent characteristics with a long cycle life.
Moreover, in the battery 1 according to the present embodiment, the restraint band 16 having a size within a range capable of covering an area of 20% or more and 90% or less with respect to the entire outer peripheral area of the electrode body 14 is externally fitted. Therefore, it is possible to prevent a short circuit between the current collecting plates 15a and 15b while maximizing the expansion restraining effect with the metal restraining band 16. Furthermore, by setting the size of the restraint band 16 in this way, the gas generated from the electrode body 14 during charging / discharging is well discharged toward the cell chamber.
(Method of forming electrode body unit 17)
Below, the formation method of the electrode body unit 17 which has the characteristics in this Embodiment is demonstrated using FIG. 3 and FIG.

(1) Formation of the electrode body 14 First, as shown to Fig.3 (a), (b), the positive electrode plate 141 is accommodated inside the bag-shaped separator 143. As shown in FIG. The separator 143 has a bag shape sealed on three sides, and the X-direction dimension in the internal space is set slightly smaller than the X-direction width dimension of the positive electrode plate 141. When the positive electrode plate 141 is accommodated in the separator 143 having such a size relationship, a part of the positive electrode plate 141 is exposed on the lower left side in the X direction as shown in FIG.

A plurality of separators 143 accommodating positive electrode plates 141 are prepared inward, and negative electrode plates 142 are sandwiched between separators 143, respectively. In this way, the positive electrode plate 141 and the negative electrode plate 142 are sequentially laminated in the Y direction, and the electrode body 14 is completed.
(2) External Fit of Restraint Band 16 Next, a method for externally fitting the restraint band 16 to the outer periphery of the electrode body 14 will be described with reference to FIG.

  The restraint band 16 is externally fitted in the X direction while keeping the laminated form of the electrode body 14 formed by laminating the positive and negative bipolar plates 141 and 142. The restraint band 16 is made of Ni-plated SPCD as described above, and is an annular body having an opening 16a having a size substantially equal to the cross-sectional size of the electrode body 14 in the YZ plane direction. For this reason, it is not necessary to use a special device when the restraint band 16 is externally fitted. The restraint band 16 is merely slid in the upper right direction in the X direction while applying a slight compressive force to the electrode body 14 in the Y direction. it can.

(3) Joining of Current Collector Plates 15a and 15b Next, a method for joining the current collector plates 15a and 15b to the electrode body 14 with the restraining band 16 fitted on the outer periphery will be described with reference to FIG. .
As shown in FIG. 4B, each of the current collector plates 15a and 15b has a strip shape elongated in the Z direction. The Y-direction width dimension of the current collector plates 15a and 15b is set to be approximately equal to the Y-direction dimension of the electrode body 14, and the Z-direction height dimension is set to be higher than the Z-direction dimension of the electrode body 14. . And the junction part 15p which is a location used as a welding point when connecting between each electrode body unit 17 is previously formed in the Z direction upper direction in each current collecting plate 15a, 15b.

For joining the current collector plates 15a and 15b to the electrode body 14, a resistance welding method, a laser welding method, or the like can be used. Moreover, you may give the burring process to the joining area | region with the electrode body 14 in each of each current collecting plate 15a, 15b.
(Effect confirmation experiment)
Below, the experiment implemented in order to confirm the predominance of the battery concerning the present invention is explained.

(Production of electrode body)
Nickel positive electrode plate: A substrate made of nickel foam having a thickness of 1.7 (mm) is filled with a predetermined amount of an active material slurry containing nickel hydroxide powder on which a highly conductive film of a sodium-containing cobalt compound is formed, and then dried. Then, rolling was performed until the thickness became 0.50 (mm) and cut into a predetermined size to produce a non-sintered nickel positive electrode plate.

Hydrogen storage alloy negative electrode plate: A hydrogen storage alloy paste is applied to both sides of a core made of punching metal, dried at room temperature, rolled to a predetermined thickness, cut into a predetermined size, and then a hydrogen storage alloy A negative electrode plate was produced.
Separator: A separator made of polypropylene non-woven fabric was sealed on three sides and processed into a bag shape.

Formation of electrode body: A nickel positive electrode plate was accommodated in a separator bag, and an electrode body was formed by alternately laminating this and a hydrogen storage alloy negative electrode plate.
(Example 1)
A constraining band having a size covering 10% of the total surface area of the outer periphery of the electrode body was externally fitted in the same manner as in the above embodiment. The restraint band made of Ni-plated SPCD and having a thickness of 0.5 (mm) was used. Subsequently, a current collector plate was joined to each of the positive and negative electrode plates of the electrode body to produce an electrode body unit. Six such electrode body units were prepared and stored separately for each cell chamber of the case as shown in FIG. 1, and the current collector plates were welded together. Thereafter, an electrolytic solution was injected into the case, and a lid was joined to produce a battery according to Example 1.

This battery has a voltage of 7.2 (V) and a nominal capacity of 6000 (mAh).
(Example 2)
The difference between the battery according to Example 2 and the battery according to Example 1 is the size of the restraining band that is fitted around the outer periphery of the electrode body. That is, in the battery according to Example 2, a restraining band having a size covering 20% with respect to the total surface area of the electrode body was used. About another structure, it is the same as that of the battery which concerns on Example 1. FIG.

(Example 3)
The battery according to the third embodiment is different from the batteries according to the first and second embodiments in that the restraining band has a size covering 40% with respect to the total surface area of the electrode body. . About another structure, it is the same as that of the battery which concerns on Example 1,2.
(Comparative Example 1)
The battery according to Comparative Example 1 is different from the batteries according to Examples 1 to 3 in that a binding band is not provided. The other configurations are the same.

(Comparative Example 2)
The battery according to Comparative Example 2 is different from the battery according to Example 1 in that an adhesive tape is attached to the outer periphery instead of the restraining band, and the other configurations are the same including the covering ratio. Have. The pressure-sensitive adhesive tape used in the battery according to Comparative Example 2 is formed by applying an acrylic pressure-sensitive adhesive material on a base material made of polypropylene, and has a thickness of 0.1 (mm).

In addition, the elongation rigidity in the constituent material of the restraint band used in the above (Example 1) to (Example 3) had the following relationship with each constituent material of the exterior body and the adhesive tape.
Adhesive tape <Exterior body <Restraint band (Experiment)
1. Measurement of thickness of positive electrode plate before battery assembly The thickness of the positive electrode plate was measured for each of the above Examples 1 to 3 and Comparative Examples 1 and 2, and the average thickness X per unit was calculated.

2. Cycle test Each of the batteries of Examples 1 to 3 and Comparative Examples 1 and 2 was in an atmosphere at a temperature of 45 (° C.), and SOC (State of Charge) was in the range of 20 to 80 (%) While controlling so as to be maintained, intermittent charge / discharge of 50 (A) was repeated 20000 (cycles).

3. Disassembly investigation after cycle test Each battery according to Examples 1 to 3 and Comparative Examples 1 and 2 after cycle test was disassembled, the thickness of each positive electrode plate was measured, and the average thickness Y per unit was determined from the measurement results. Was calculated. And the ratio of the average thickness before and behind a cycle test was computed about each battery. The results are listed in Table 1.

4). Measurement of change in battery series resistance The battery series resistance before and after the cycle test was measured for each battery, and the ratio was calculated. The calculated results are shown in Table 1. The battery series resistance was measured by the following method before and after the cycle test.
40 (A) discharge ⇒ 40 (A) charge ⇒ 80 (A) discharge ⇒ 80 (A) charge ⇒ 120 (A) with 30 (min.) Charge at 6 (A) and controlled to SOC 50 (%) ) Discharge ⇒ 120 (A) charge ⇒ 160 (A) discharge ⇒ 160 (A) charge steps are performed with 10 (min.) Rest periods between them, and 10 ( min.) Energized every 10 (sec.) after the rest. And each battery voltage at the time of this 10 (sec.) Progress was measured for every discharge current.

  The measurement results were plotted with the discharge current value on the horizontal axis and the battery voltage value on the vertical axis, and the battery voltages R1 and R2 were determined from the slopes of the graphs obtained.

表１に示すように、正極板の厚み変化においては、実施例１〜３に係る電池では１．０６〜１．０９の範囲内の比率であったのに対して、比較例１、２の電池では、１．１６〜１．１８の範囲内の比率となっていた。即ち、拘束バンドを有していない比較例１に係る電池では、サイクル試験前後で正極板の厚みが１８（％）も膨化し、電極体の外周に粘着テープを被着した構成の比較例２の電池でも、正極板は１６（％）も膨化した。

As shown in Table 1, in the thickness change of the positive electrode plate, in the batteries according to Examples 1 to 3, the ratio was in the range of 1.06 to 1.09, whereas in Comparative Examples 1 and 2 In the battery, the ratio was in the range of 1.16 to 1.18. That is, in the battery according to Comparative Example 1 that does not have a restraining band, Comparative Example 2 having a configuration in which the thickness of the positive electrode plate expands by 18 (%) before and after the cycle test and the adhesive tape is attached to the outer periphery of the electrode body. Even in this battery, the positive electrode plate expanded by 16%.

On the other hand, in the batteries according to Examples 1 to 3 having a restraining band made of Ni-plated SPCD, the expansion of the positive electrode plate was suppressed to 1/3 to 1/2 compared to Comparative Examples 1 and 2. . In particular, in the batteries according to Examples 2 and 3 in which the covering ratio was 20 (%) or more, only 6 (%) of the positive electrode plate was expanded.
Also, as shown in Table 1, the change in battery series resistance (R2 / R1) was 0.62 to 0.65 in the batteries according to Comparative Examples 1 and 2, whereas Example 1 In the battery according to -3, the battery was excellent at 0.89-0.93. In particular, in the batteries according to Examples 2 and 3, 0.92 and 0.93, which are 0.9 points or more, were secured even after the cycle test with respect to the battery series resistance before the cycle test.

  From the above experimental results, in each battery according to Examples 1 to 3 including the restraining band made of the Ni-plated SPCD having higher elongation rigidity than the material constituting the exterior body, the positive electrode plate is expanded due to the cycle test. Suppressed and there was little change in battery series resistance. Among them, the batteries according to Examples 2 and 3 in which the restraining band was set so as to cover 20% or more of the entire surface of the electrode body were particularly effective. Therefore, in the alkaline secondary battery, the outer periphery of the electrode body is externally fitted with a restraining band having a higher elongation rigidity than the material constituting the exterior body, thereby having an advantage from the viewpoint of the cycle life of the battery. .

In particular, when a restraint band having a size covering 20% or more of the entire surface of the electrode body is provided, the effect becomes remarkable.
In addition, when the covering ratio of the restraining band to the surface of the electrode body is set to be larger than 90 (%), although it is excellent from the viewpoint of suppressing the expansion of the positive electrode plate, it tends to cause a short circuit with the current collector plate. The discharge property of the gas discharged from the electrode body at the time of charging / discharging is impaired.

Accordingly, it is desirable that the covering ratio of the restraining band be in the range of 20 (%) to 90 (%).
(Other matters)
The above embodiment is an example of the present invention, and the present invention is not limited to the above embodiment. For example, in the above embodiment, the Ni-MH battery is taken as an example. However, the type of battery is not limited to this as long as it is an alkaline sealed secondary battery, such as a Ni-Cd battery or a Li battery. It can also be applied.

Moreover, in the said embodiment, although the battery 1 provided with the six electrode body units 17 inside was used, the accommodation number etc. of the electrode body unit 17 are not limited to this.
In addition, the materials of the electrode plates 141 and 142 and the material of the restraining band 16 employed in the battery 1 according to the above embodiment can be changed as appropriate in the present invention. However, as a material used for the configuration of the restraining band 16, it is desirable to use a material whose elongation per unit area is at least smaller than the material forming the case 10.

  Furthermore, although the alkaline sealed secondary battery is taken as an example in the above embodiment, the same effect as described above can be obtained by applying the present invention to an open-type alkaline secondary battery.

  The present invention is particularly useful for realizing an alkaline secondary battery having a configuration in which an electrode body is housed in an outer package made of a synthetic resin material such as a HEV battery.

1 is an exploded perspective view of an alkaline sealed secondary battery 1 according to an embodiment. (A) is an external appearance perspective view of the electrode body unit 17 of the alkaline sealed secondary battery 1, and (b) is an AA cross-sectional view thereof. (A) is a perspective view which shows the lamination | stacking process of the electrode body 14, (b) is the BB sectional drawing. (A) is a perspective view which shows the process of inserting the restraint band 16 in the outer periphery of the electrode body 14, (b) shows the joining process of the collector plates 15a and 15b for positive / negative bipolar electrodes to the electrode body 14. FIG. It is a perspective view.

Explanation of symbols

1. Alkaline secondary battery 10. Case 11. Lid 12. Safety valve 14. Electrode bodies 15a, 15b. Current collecting plate 16. Restraint band 17. Electrode unit 141. Positive plate 142. Negative electrode plate 143. Separator

Claims (7)

An electrode body in which a positive electrode plate and a negative electrode plate are sequentially stacked with a separator interposed therebetween is an alkaline secondary battery housed inside an exterior body,
The electrode body is in a state in which a restraining member is externally fitted to a part of the outer periphery of the electrode body, and the other area is exposed inside the exterior body,
The alkaline secondary battery, wherein the restraining member has alkali resistance, and the constituent material has a higher elongation rigidity than a material constituting the exterior body. The alkaline secondary battery according to claim 1, wherein the restraining member is an annular body that covers an area of 20% to 90% with respect to the total surface area of the electrode body. The exterior body is made of a resin material,
The restraint member is made of a metal material,
The alkali secondary according to claim 1, wherein the electrode body is formed in a state in which the separator is interposed between at least one of the positive electrode plate and the negative electrode plate and the restraining member. battery. The separator has a bag shape,
At least one of the positive electrode plate and the negative electrode plate is housed inside the separator and is in a state where a partial region is exposed from an opening portion of the separator formed in a non-existing region of the restraining member,
The electrode body is configured such that each of the positive electrode plate and the negative electrode plate is alternately laminated so that end portions of each electrode plate protrude, and a current collector plate is joined to each end portion. The alkaline secondary battery according to claim 3. The alkaline secondary battery according to any one of claims 1 to 4, wherein the alkaline secondary battery has a sealed structure. A plurality of the electrode bodies are accommodated in the exterior body,
The internal space of the exterior body is divided into a plurality of cell chambers according to the number of stored electrode bodies,
The alkaline secondary battery according to any one of claims 1 to 5, wherein each of the plurality of electrode bodies is housed separately for each cell chamber and is connected in series. An electrode body forming step in which a separator is sandwiched between each other, and a positive electrode plate and a negative electrode plate are sequentially laminated to form an electrode body;
An outer fitting step of fitting an annular restraining member to the electrode body from a direction intersecting the stacking direction of the electrode bodies;
A current collector plate joining step for joining two current collector plates respectively to both side portions of the electrode body in the direction of external fitting of the restraining member;
The step of storing the electrode body after the current collector plate bonding, in the internal space of the case, and injecting an electrolyte into the internal space;
A sealing step for sealing the opening by placing a lid on the opening of the case and joining them together;
The method for manufacturing an alkaline secondary battery, wherein the constraining member used in the external fitting step is made of an alkali-resistant material and has a higher elongation rigidity than a material constituting the case.

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