JP2011204469A - Square sealed secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a square sealed secondary battery more improved in safety and reliability against a rise of the internal pressure of the battery and leakage of electrolyte by improving an impact resistance of the square sealed secondary battery relative to external force such as vibration force and a fall impact, while properly maintaining sensitivity of a gas discharge valve.SOLUTION: In this square sealed secondary battery, a seal plate including the gas discharge valve is disposed, and an insulating plate and a spacer are disposed under the seal plate. The insulating plate having a peripheral edge wall part 201 and/or the spacer having a peripheral edge wall part is provided with a bridging part 202 or a pair of ribs to reinforce the impact resistance of these members.

Description

  The present invention relates to a technique for increasing impact resistance of a rectangular sealed secondary battery.

  In recent years, mobile electronic devices such as mobile phones and laptop computers that use secondary batteries as a drive source, hybrid vehicles (HEV), and electric vehicles (EV) are making rapid progress. There is a need for excellent secondary batteries.

  When the sealed battery is left in a high temperature environment or overcharged, the battery internal pressure increases, but the increase in the battery internal pressure causes the battery to burst. For this reason, the sealed battery incorporates a gas discharge valve that discharges the gas that is the cause of the battery internal pressure to the outside of the battery when the battery internal pressure increases to a certain value or more. The gas discharge valve is preferably one that responds sensitively to changes in gas pressure from the viewpoint of enhancing safety against the gas inside the battery.

  However, battery safety cannot be achieved by only increasing the sensitivity of the gas discharge valve. For example, when a battery or a battery-mounted device is vigorously vibrated or accidentally dropped, the pressure inside the battery fluctuates, and the pressure rises momentarily near the gas discharge valve. There is. Such a momentary increase in battery internal pressure may cause the gas discharge valve to operate. As a result, there is a problem that the electrolyte leaks out of the battery and damages the equipment around the battery.

  In other words, from the viewpoint of enhancing the safety against the gas generated inside the battery, a gas discharge valve that reacts sensitively to changes in gas pressure is preferable, but from the viewpoint of preventing malfunction, it does not operate due to vibration or a drop impact. A gas exhaust valve that is not too high is desirable. However, it is difficult to realize a gas discharge valve that satisfies these two conflicting requirements.

  For this reason, Patent Document 1 arranges an insulating plate between a power generation element in a battery can and a lid having a gas discharge valve that covers the battery can, and the insulating plate is used for the gas discharge valve portion. We have proposed a technology that increases the durability against drop impacts by covering the entire surface.

  Patent Document 2 proposes a gas discharge valve mechanism incorporating a temperature sensor for detecting battery temperature.

JP 2008-192414 A Japanese Patent Laid-Open No. 11-25938

  The object of the present invention is to increase the impact resistance when a vibration force or a drop impact force is applied to the battery while maintaining the sensitivity of the gas discharge valve appropriately, thereby ensuring safety and reliability against battery internal pressure and electrolyte leakage. Is to further increase

  A first invention relating to a rectangular sealed secondary battery for solving the above-described problem is that a positive electrode plate having a positive electrode tab and a negative electrode plate having a negative electrode tab are wound and processed into a flat shape via a separator. An electrode body, a bottomed rectangular battery can that accommodates the electrode body, a sealing plate that seals an opening of the battery can, and a gas exhaust valve, and the electrode body that is accommodated in the battery can An insulating spacer disposed above and an insulating plate disposed between the spacer and the sealing plate, the spacer and the insulating plate covering the sealing plate side of the electrode body In the square sealed secondary battery arranged in the above, the insulating plate has a substantially rectangular shape with a through-hole through which gas can pass, and the height of the insulating plate peripheral wall constituting the outer peripheral edge of the insulating plate is , Higher than the inside, and in the straight part of the peripheral wall of the insulating plate Insulating plate bridge which extends to the opposite sides are formed, characterized in that.

  The “substantially rectangular shape” of this configuration includes a rectangular shape, a shape in which four corners of the rectangle are dropped, or a track shape having a pair of semicircular corners and a substantially straight portion connecting both corners. "Shaped shape" includes a shape with rounded corners and a shape with obtuse angles (the same applies hereinafter).

  According to the said structure, an insulating board bridge | crosslinking part reinforces the intensity | strength of an insulating board and acts so that the space volume between the spacers under an insulating board may be hold | maintained. Therefore, an instantaneous pressure increase generated by an external impact force is alleviated, and as a result, malfunction of the gas discharge valve is suppressed. The malfunction of the gas discharge valve results in electrolyte leakage and the end of the battery life, and the electrolyte leakage damages the device in which the battery is incorporated, but according to the above configuration, due to the simple structure of adding a bridging part, A highly reliable square sealed secondary battery in which the gas discharge valve does not operate unnecessarily can be realized.

  The second invention is a rectangular sealed secondary battery according to the first invention, wherein the square sealed secondary battery has a substantially rectangular shape provided with a through-hole through which a gas can pass instead of the insulating plate. The insulating plate peripheral wall portion constituting the height of the insulating plate peripheral wall portion is higher than the inner side thereof, and a pair of insulating portions is formed in the opposing straight portion of the insulating plate peripheral wall portion and the portion having the through hole in the middle. An insulating plate in which ribs extending from each of the plate peripheral wall portions to the front of the through hole are formed is used.

  In this configuration, the pair of ribs provided on the insulating plate acts so as to maintain the space volume between the spacers below the insulating plate. As a result, the same effects as those of the first invention can be obtained.

    According to a third aspect of the present invention, there is provided an electrode body in which a positive electrode plate having a positive electrode tab and a negative electrode plate having a negative electrode tab are wound through a separator and processed into a flat shape, and the electrode body is accommodated. A bottom square battery can, a sealing plate provided with a gas exhaust valve for sealing the opening of the battery can, an insulating spacer disposed above the electrode body housed in the battery can, and An insulating plate disposed between a spacer and the sealing plate, wherein the spacer and the insulating plate are disposed so as to cover the sealing plate side of the electrode body. Is a substantially rectangular shape having a slit through which gas and a negative electrode tab can pass, and the height of the spacer peripheral wall portion constituting the outer peripheral edge of the spacer is higher than the inside thereof, and the spacer peripheral wall On the opposite side of the straight part. Bridge extending is formed, characterized in that.

  In this configuration, the bridging portion provided in the spacer acts so as to maintain the space volume with the insulating plate. As a result, the same effects as those of the first invention can be obtained.

  Further, a fourth invention is a rectangular sealed secondary battery according to the third invention, wherein the square sealed secondary battery has a substantially rectangular shape provided with a slit through which a gas and a negative electrode tab can be passed instead of the spacer. The height of the spacer peripheral wall portion constituting the outer peripheral edge of the spacer is higher than the inside thereof, and is a straight portion of the spacer peripheral wall portion where the slit is located between the opposing spacer peripheral wall portions In addition, a spacer in which a rib extending from each of the pair of spacer peripheral wall portions to the front of the slit is formed is used.

  In this configuration, the pair of ribs provided on the spacer acts so as to maintain the space volume with the insulating plate. As a result, the same effects as those of the first invention can be obtained.

  According to a fifth aspect of the present invention, in the prismatic sealed secondary battery according to the first aspect, the spacer has a substantially rectangular shape with a slit through which a gas and a negative electrode tab can pass. The height of the spacer peripheral wall portion constituting the peripheral edge is higher than the inside thereof, and a bridging portion extending to the opposite side is formed in the linear portion of the spacer peripheral wall portion. .

  In this configuration, since both the bridging portion provided on the insulating plate and the bridging portion provided on the spacer act so as to maintain the space volume between the insulating plate and the spacer, the space volume can be more reliably maintained. .

According to a sixth aspect of the present invention, in the prismatic sealed secondary battery according to the first aspect, the spacer has a substantially rectangular shape having a slit through which gas and a negative electrode tab can pass. The height of the spacer peripheral wall portion constituting the periphery is higher than the inside thereof,
Ribs extending from each of the pair of spacer peripheral wall portions to the front of the slit are formed in the straight portion of the spacer peripheral wall portion where the slit is located between the opposing spacer peripheral wall portions. It is characterized by that.

  In this configuration, both the bridging portion provided on the insulating plate and the pair of ribs provided on the spacer act so as to maintain the space volume between the insulating plate and the spacer, so that the space volume can be more reliably maintained. it can.

  According to a seventh aspect of the present invention, in the prismatic sealed secondary battery according to the second aspect of the present invention, the spacer has a substantially rectangular shape with a slit through which gas and a negative electrode tab can pass. The height of the spacer peripheral wall portion constituting the peripheral edge is higher than the inside thereof, and a bridging portion extending to the opposite side is formed in the linear portion of the spacer peripheral wall portion. .

  In this configuration, both the pair of ribs provided on the insulating plate and the bridging portion provided on the spacer act so as to maintain the space volume between the insulating plate and the spacer, so that the space volume can be more reliably maintained. it can.

  An eighth invention is the prismatic sealed secondary battery according to the second invention, wherein the spacer has a substantially rectangular shape with a slit through which gas and a negative electrode tab can pass. A pair of spacer peripheral wall portions constituting the peripheral edge have a height higher than the inner side thereof, and a straight portion of the spacer peripheral wall portion where a slit is positioned between the opposing spacer peripheral wall portions. Ribs extending from each of the spacer peripheral wall portions to the front of the slit are formed.

  In this configuration, both the pair of ribs provided on the insulating plate and the pair of ribs provided on the spacer act so as to maintain the space volume between the insulating plate and the spacer. Can do.

  According to a ninth invention, in the rectangular sealed secondary battery according to any one of the first to eighth inventions, the insulating plate bridging portion and the spacer bridging portion are configured such that the gas discharge valve of the sealing plate is connected to the battery can axis direction. It is characterized in that it is located in the vicinity of the projection plane, not in the projection plane.

  When the bridging portion is in the gas passage, smooth discharge of the gas in the battery is disturbed. Therefore, it is preferable that the bridging portion be positioned not in the projection plane when the gas discharge valve is projected in the battery can axis direction but in the vicinity of the projection plane. This is because the projection plane is the shortest path from the gas generated in the battery to the sealing plate gas discharge valve, and it is preferable to secure this path as a gas passage.

  According to a tenth aspect of the invention, in the rectangular sealed secondary battery according to any one of the second to eighth aspects of the invention, the insulating plate rib and the spacer rib project the gas discharge valve of the sealing plate toward the battery can axis. And is located in or near the projection plane.

  Unlike the bridging portion, the rib has a structure that does not block the through hole or slit, which is a passage for gas, so that the passage of gas is not obstructed even in the projection plane. Therefore, the rib is preferably positioned in the projection plane or in the vicinity thereof.

  According to the present invention, since the impact resistance of the battery when a vibration force or a drop impact force is applied to the battery can be remarkably enhanced, the safety of the battery internal pressure and electrolyte leakage is maintained while maintaining the sensitivity of the gas discharge valve appropriately. It is possible to provide a square sealed secondary battery that is excellent in reliability and reliability.

1 is an external perspective view of a square sealed secondary battery according to Example 1. FIG. FIG. 2 is a cross-sectional view when the line XX in FIG. 1 is lowered vertically. Fig.3 (a) is a top view which shows the back surface of the insulating board which has a bridge | crosslinking part, (b) is a side view. FIG. 4 is a perspective view showing a back surface shape of the insulating plate having the bridging portion shown in FIG. Fig.5 (a) is a top view of the front surface of the spacer which has a bridge | crosslinking part, (b) is a YY sectional view taken on the line. FIG. 6 is a perspective view showing a front surface shape of a spacer having a bridging portion shown in FIG. FIG. 7A is a plan view of a front surface of a spacer having ribs, and FIG. 7B is a cross-sectional view taken along line YY. FIG. 8 is a cross-sectional view taken along the line Z-Z in FIG. Fig.9 (a) is a top view of the back surface of the insulating board which has a rib, (b) is a YY sectional view taken on the line. FIG. 10 is a perspective view showing the back surface shape of the insulating plate having the rib shown in FIG. FIG. 11 is a plan view of a front surface of a spacer provided with neither a bridging portion nor a rib, and (b) is a cross-sectional view taken along line YY. FIG. 12 is a plan view of the back side of the insulating plate in which neither the bridging portion nor the rib is provided, and (b) is a cross-sectional view taken along the line YY. FIG. 13 is a plan view of the back surface of an insulating plate in which neither a bridging portion nor a rib is provided and only one through hole is provided, and (b) is a cross-sectional view taken along line YY. FIG. 14 shows an insulating plate having a structure in which neither a bridging portion nor a rib is provided and a through hole on one end side is provided on a flat surface, (A) is a plan view of the back surface, and (b). Is a cross-sectional view taken along line YY. FIG. 15 shows a spacer having a structure in which neither a bridging portion nor a rib is provided and a slit on one end side is provided on a flat surface, (A) is a plan view of its front surface, and (b) is a plan view of its front surface. It is a YY line sectional view.

  An embodiment for carrying out the present invention will be described using a rectangular sealed secondary battery using a flat spiral electrode body.

Example 1
A square sealed secondary battery according to Example 1 was manufactured as follows. A positive electrode active material made of lithium cobalt oxide (LiCoO ₂ ), a carbon-based conductive agent such as acetylene black or graphite, and a binder such as polyvinylidene fluoride (PVDF) are mixed with an organic solvent (for example, N-methyl-2-pyrrolidone). The positive electrode active material slurry was prepared by mixing the binder solution dissolved in (1) at an appropriate ratio. This positive electrode active material slurry was applied to a strip-shaped aluminum foil and dried to form a positive electrode plate 107.

  On the other hand, a negative electrode active material slurry was prepared by appropriately mixing graphite powder as a negative electrode active material, a binder (for example, styrene butadiene rubber), a thickener (for example, carboxymethyl cellulose), and water. This slurry was applied to a strip-shaped copper foil and dried to form a negative electrode plate 106.

  The positive electrode plate and the negative electrode plate are overlapped with a separator made of a polyolefin-based microporous film interposed therebetween, wound up with a winder, and then terminated with an insulating winding tape to wind up the wound body It was. The wound body was pressure-molded to form a flat electrode body 108.

  This electrode body is configured such that the positive electrode core (aluminum foil) is exposed at the outermost periphery, and a cut portion for cutting out a part of the aluminum foil is formed in advance at a portion located at the outermost periphery. After making it a take-up electrode body with a winder, the cut portion was raised to form a positive electrode tab. On the other hand, a tab made of nickel was previously attached to the winding start end side of the strip-shaped copper foil as the negative electrode core, and this was used as the negative electrode tab.

  The battery assembly procedure will be described with reference to FIGS. FIG. 1 is an external view of a rectangular sealed secondary battery of Example 1, and FIG. 2 is a cross-sectional view when the XX line of FIG. 1 is lowered vertically. 3A is a plan view of the back surface of the insulating plate 200 as viewed from the inside of the battery, and FIG. 3B is a cross-sectional view taken along line YY in FIG. FIG. 4 is a perspective view of the insulating plate 200 as seen from the battery inner side (back side). 11 shows a spacer 600 having no reinforcing structure used in Example 1, (a) is a plan view of the front surface of the spacer 600, and (b) is a cross-sectional view taken along line YY in (a).

[Preparation of sealing body]
The sealing plate 102 made of aluminum alloy provided with the gas discharge valve 103, the liquid injection port 105, and the electrode external terminal mounting hole 104 'and the insulating plate 200 are connected to the electrode external terminal hole 104' and the insulating plate fastening hole 204. The gasket and the electrode internal terminal member were arranged at predetermined positions, and the electrode external terminal was inserted into the hole and crimped by a known method to form a sealing body in which the members were integrated.

[Battery assembly]
The flat electrode body 108 was accommodated in the rectangular battery can 101, and a spacer 600 made of an insulating resin was disposed above the electrode body 108. At this time, a positive electrode tab was sandwiched between the inner wall of the prismatic battery can 101 and the end portion of the spacer 600, and the tip thereof was led to the opening of the battery can 101 along the inner wall of the battery can 101. On the other hand, the negative electrode tab was guided upward through one slit 603 of the spacer 600 and connected to the electrode internal terminal member of the sealing body.

Thereafter, the sealing body was covered with the rectangular battery can 101, and the entire periphery of the fitting portion was laser welded in a state where the positive electrode tab was sandwiched between the fitting portion of the sealing plate and the battery can. Thereafter, an electrolytic solution was injected from the injection port 105, and then a sealing plug was inserted into the injection port 105 and laser welding was performed to fix the sealing plug. As the electrolytic solution, an electrolytic solution in which LiPF ₆ was dissolved in a mixed solvent of ethylene carbonate, ethyl methyl carbonate, and diethyl carbonate was used.

  Thus, a rectangular sealed secondary battery having a battery external thickness of 5.2 mm, a width of 34 mm, and a height of 50 mm and a battery capacity of 1050 ItA was completed.

  Next, the structure of the insulating plate 200 (with the reinforcing structure) and the spacer 600 (without the reinforcing structure), which are the main members of the rectangular sealed secondary battery according to the first embodiment, will be described.

[Insulating plate]
As shown in FIGS. 3 and 4, the insulating plate 200 has a track shape in which both end portions are semicircular and the central portion in the longitudinal direction is slightly recessed inward. Its length (longitudinal length) is 32 mm, and its width (longitudinal length) is 4.0 mm. 3 and 4, reference numeral 201 denotes an insulating plate peripheral wall portion, and the insulating plate peripheral wall portion 201 on the back surface has a height (thickness) higher than the inner side thereof. The wall thickness (overall height) is 0.7 mm, the width is 0.4 mm, and the inner wall thickness is set to 0.3 mm.

  A fastening hole 204 is provided at the center of the insulating plate 200, and through holes 203 and 203 are provided on the left and right sides thereof. In addition, the insulating plate 200 is connected to the insulating plate 200 so that the two sides in the longitudinal direction (the opposing long sides of the insulating plate peripheral wall 201) are connected to each other slightly closer to the center than the one through hole 203. A unit 202 is provided. The insulating plate bridging portion 202 plays a role of reinforcing the strength of the insulating plate, and is formed to have the same thickness (0.7 mm) and width (0.4 mm) as the opposing long sides of the insulating plate peripheral wall portion 201. Has been. In addition, the bridging portion 202 is formed by positioning in advance in relation to the insulating plate so as to be disposed in the vicinity immediately below the gas discharge valve 103 when the insulating plate 200 is disposed below the sealing plate 102. Has been.

  Further, as shown in FIG. 4B, the insulating plate 200 is formed with convex portions 205 protruding downward at both end portions (corner portions) of the insulating plate peripheral wall portion 201 on the back surface side. The convex portion 205 is a portion to be fitted with a concave portion 304 of a spacer which will be described later. However, the convex portion 205 and the concave portion 304 are not indispensable elements. Here, the lower side means the bottom direction of the battery can, and the upper side means the opening side (external terminal side) of the battery can.

  There may be at least one through hole 203, but the through hole 203 is preferably positioned directly below the gas exhaust valve 103. Moreover, although the insulating plate bridge | bridging part 202 was made into one in Example 1, a bridge | crosslinking part can also be provided in two or more places.

[Spacer]
As shown in FIGS. 11A and 11B, the spacer 600 has a semicircular track shape at both ends, a length (longitudinal length) of 32 mm, and a width (short side length) of 4. .0 mm is set. In the figure, reference numeral 301 denotes a spacer peripheral wall portion, which has a shape in which the inside of the spacer peripheral wall portion 301 on the front surface is recessed. The spacer peripheral wall portion 601 has a thickness (overall height) of 0.6 mm and a width of 0.3 mm, and the inner thickness surrounded by the peripheral wall portion is 0.3 mm.

  In addition, two slits 603 and 603 each having a through hole are provided in a region surrounded by the spacer peripheral wall portion 601. Further, concave portions 304 are formed on both ends of the spacer 600 in the longitudinal direction, and the convex portions 205 of the insulating plate 200 described above are fitted into the concave portions 304. There may be at least one slit 603, and the slit 603 functions as a hole through which the negative electrode tab passes and also functions as a hole through which the gas inside the battery passes. When there is one slit, it is preferably provided at a position facing the gas discharge valve 103.

  The insulating plate 200 and the spacer 600 can be manufactured by a mold molding method, an injection molding method, or other methods. Examples of the material resin include polypropylene, tetrafluoroethylene-perfluoroalkyl vinyl ether polymerized resin, and ethylene-tetrafluoroethylene. A material that has an insulating property and does not react with the electrolytic solution, such as a polymer resin, polytetrafluoroethylene, polyphenylene sulfide resin, or polyether ether ketone resin, can be used. In addition to the track shape as described above, the shape may be a rectangular shape, or may be similar to the planar shape of the sealing plate or the cross-sectional shape of the outer can. Then, insulation is performed so as to cover the sealing plate side of the electrode body so that the sealing plate does not contact the electrode body.

  Note that, as for the reference numerals, the same numerals are assigned to the same structure and the same function in principle. For example, parts having the same reference numerals in FIGS. 11 and 5 and 6 have the same structure and the same function.

(Example 2)
In the square sealed secondary battery according to Example 2, the insulating plate 200 having the same bridging portion as in Example 1 was used. Moreover, the spacer 300 which has a bridge | crosslinking part was used also about the spacer. Except for this, a square sealed secondary battery was fabricated in the same manner as in Example 1.

  The structure of the spacer 300 used in Example 2 will be described with reference to FIGS. 5A is a plan view of the spacer front surface, and FIG. 5B is a cross-sectional view taken along line YY in FIG. 5A. FIG. 6 is a perspective view of the spacer 300. As shown in FIGS. 5 and 6, the spacer 300 has a semicircular track shape at both ends, like the spacer according to the first embodiment, and has a longitudinal length of 32 mm and a lateral length of 4.0 mm. Is set to The spacer peripheral wall 301 has a wall thickness (overall height) of 0.6 mm and a width of 0.3 mm, and the inner wall surrounded by the peripheral wall is 0.3 mm.

  However, unlike the spacer 600 used in the first embodiment, the spacer 300 according to the second embodiment has slits 303, 305, and 306 from the left to the middle, small, and large in the region surrounded by the spacer peripheral wall 301. Three spacer bridging portions 302 are provided between the middle and small slits. The spacer bridging portion 302 has the same thickness (0.6 mm) and width (0.3 mm) as the pair of opposing long sides of the spacer peripheral wall portion 301, and is formed so as to connect both long sides. The spacer bridging portion 302 is provided in the vicinity of the lower projection surface of the gas exhaust valve 103, and mainly serves as a barrier that reinforces the strength of the spacer 300 in the width direction and suppresses the compression of the space volume between the insulating plate and the spacer. Have a role.

  As in the case of the insulating plate, two or more spacer bridging portions 302 can be provided. Further, at least one slit 303 is sufficient.

(Example 3)
In Example 3, the insulating plate 700 having no bridging portion shown in FIG. 12 was used, and the spacer 300 (see FIG. 5) having the bridging portion similar to that used in Example 2 was used as the spacer. About the matter other than this, it carried out similarly to Example 1, and the square sealed secondary battery concerning Example 3 was produced.

  The insulating plate 700 used in Example 3 is the same as the insulating plate 200 except for the above-described insulating plate 200 (see FIGS. 3 and 4) in that the bridging portion 202 is not formed. Therefore, the description is omitted.

Example 4
In Example 4, the insulating plate 700 (see FIG. 12) having no bridging portion used in Example 3 was used, and the spacer 400 having the ribs 402 and 402 shown in FIG. 7 was used as the spacer. About the matter other than this, it carried out similarly to Example 1, and the square sealed secondary battery concerning Example 4 was produced. Therefore, the structure of the spacer 400 having ribs will be described here.

  FIG. 7A shows a plan view of the front surface of the spacer 400, and FIG. 7B shows a cross-sectional view taken along line YY in FIG. 7A. FIG. 8 is a cross-sectional view taken along the line ZZ in FIG. The spacer 400 has a spacer peripheral wall portion 301 having a thickness (overall height) of 0.6 mm and a width of 0.3 mm, and an inner thickness surrounded by the peripheral wall portion is 0.3 mm. As shown in FIG. 7A and FIG. 8, the rib 402 extends from a pair of long sides (longitudinal sides of the spacer peripheral wall 301) to the front of the slit 303 provided between the pair of long sides. It is an extended structure. The thickness (0.6 mm) and width (0.3 mm) are the same as those of the spacer peripheral wall, the length protruding from the spacer peripheral wall is 1.2 mm, and the gap between the tip of the rib 402 and the slit 306 is set. An interval of 0.3 mm is provided so that the rib does not hang over the slit 306.

  The rib 402 also functions as a barrier that suppresses the compression of the space volume between the insulating plate and the spacer, as in the spacer bridging portion described in the second embodiment. However, the rib 402 does not obstruct gas passage, It can be formed on or near the gas discharge valve projection surface from above the discharge valve 103.

(Example 5)
In Example 5, the insulating plate 200 (see FIGS. 3 and 4) having the bridging portion 202 and the spacer 400 (see FIG. 7) having the ribs 402 and 402 described above were used. About the matter other than this, it carried out similarly to Example 1, and the square sealed secondary battery concerning Example 5 was produced.

(Example 6)
In Example 6, the insulating plate 500 shown in FIGS. 9 and 10 having ribs and the spacer 600 of FIG. 11 having no reinforcing structure are used, and the other matters are the same as in Example 1 in Example 5. Such a square sealed secondary battery was produced.

  The insulating plate 500 is different from the insulating plate 200 shown in FIGS. 3 and 4 only in that it has ribs 502 and 502 but does not have the insulating plate bridging portion 202. As shown in FIG. 9 (back surface plan view) and FIG. 10 (back surface perspective view), the insulating plate ribs 502 and 502 are formed from a pair of long sides (longitudinal direction sides of the insulating plate peripheral wall 201). This structure extends to the front of the through hole 203 provided between the sides. Its thickness (0.7 mm) and width (0.4 mm) are the same as those of the peripheral wall of the insulating plate, the length protruding from the peripheral wall of the spacer is 1.2 mm, and it should not be placed over the through hole 203. It is.

  The insulating plate ribs 502 and 502 play a role of preventing malfunction of the gas discharge valve due to the compression of the space volume, like the insulating plate bridging portion 202 described in the first embodiment. As is apparent from FIGS. 9 and 10, the insulating plate ribs 502 and 502 do not interfere with the passage of gas, and unlike the case of the insulating plate bridging portion 202 described above, the gas discharge valve 103 is projected from above toward the bottom of the battery can. It may be formed on the projection surface of the gas discharge valve 103 at that time.

(Comparative Example 1)
In Comparative Example 1, an insulating plate 700 ′ having the same shape as that of the above-described insulating plate 700 (see FIG. 12) and a wall thickness of the insulating plate peripheral wall 1 mm smaller than that of the above-described insulating plate 700 was used. That is, the thickness of the peripheral wall portion of this insulating plate is 0.6 mm, the side width in the longitudinal direction is 0.3 mm, and the inner thickness surrounded by the peripheral wall portion of the insulating plate is 0.3 mm.

  Moreover, about the spacer, the spacer 600 (refer FIG. 11) which does not have the bridge | crosslinking part used in Example 1 was used. About the other matter, it carried out similarly to Example 1, and produced the square sealed secondary battery concerning the comparative example 1. FIG.

(Comparative Example 2)
In Comparative Example 2, the thickness of the peripheral wall of the insulating plate is 0.8 mm, and the same as the insulating plate 700 having no bridging portion in FIG. 12 except that the side width in the longitudinal direction is 0.5 mm. The shape of the insulating plate 700 ″ was used. Also, the spacer was used in Example 1 except that the spacer peripheral wall was 0.8 mm thick and the longitudinal side width was 0.5 mm. The spacer 600 ′ having the same shape as the spacer 600 having no bridging portion shown in FIG.11 was used, and the rectangular sealed secondary battery according to the comparative example 2 was manufactured in the same manner as in the example 1 with respect to other matters. did.

(Comparative Example 3)
In Comparative Example 3, the insulating plate 800 shown in FIG. 13 with one through hole as a gas passage is used, and the spacer 600 (FIG. 11) having no bridging portion similar to that in Example 1 is used as the spacer. For other matters, a rectangular sealed secondary battery according to Comparative Example 3 was fabricated in the same manner as in Example 1.

  The insulating plate 800 (FIG. 11) is the same as the insulating plate 700 (FIG. 12) except that one through hole is used and the thickness of the insulating plate peripheral wall is reduced by 1 mm. The thickness of 201 is 0.6 mm, the side width in the longitudinal direction is 0.3 mm, and the inner thickness of the peripheral wall of the insulating plate is 0.3 mm.

(Comparative Example 4)
In the comparative example 4, the insulating plate 900 shown in FIG. 14 is used, and the spacer is the spacer 600 (FIG. 11) that does not have the same bridging portion as in the first embodiment. Similarly, a square sealed secondary battery according to Comparative Example 4 was produced.

  As shown in FIG. 14, the insulating plate 900 has a semicircular track-shaped one end portion which is an insulating plate flat surface 902 having no depression, and one through hole 903 is formed on the insulating plate flat surface 902. Is formed. The portion excluding the insulating plate flat surface 902 has the same shape as the insulating plate 500 (FIG. 12), and a fastening hole 204 and another through hole 203 are formed in the inner region of the insulating plate peripheral wall 901. Has been. The thickness of the insulating plate peripheral wall portion 901 is 0.6 mm, the side width in the longitudinal direction is 0.3 mm, and the inner thickness of the insulating plate peripheral wall portion is 0.3 mm. The thickness of the insulating plate flat surface 902 is 0.6 mm, which is the same as that of the insulating plate peripheral wall 901. FIG. 14 is a plan view seen from the back side.

(Comparative Example 5)
In Comparative Example 5, the shape of the insulating plate is the same as that of the insulating plate 900 shown in FIG. 14, but the thickness of the insulating plate peripheral wall portion 901 and the thickness of the insulating plate flat surface 902 are larger than those of the insulating plate 900 described above. A thick insulating plate 900 ′ was used. That is, the insulating plate peripheral wall portion 901 is 0.7 mm, the side width in the longitudinal direction is 0.4 mm, the inner thickness of the insulating plate peripheral wall portion is 0.3 mm, and the insulating plate flat surface 902 is thick. An insulating plate having a thickness of 0.7 mm was used. This insulating plate is referred to as an insulating plate 900 ′ (not shown).

  As the spacer, a spacer 1000 shown in FIG. 15 was used. As shown in FIG. 15, the spacer 1000 has a semi-circular track-shaped one end on both sides of a spacer flat surface 1002 having no recess, and one slit 1003 is formed on the spacer flat surface 1002. Yes. The spacer peripheral wall portion 301 has a thickness of 0.6 mm, the side width in the longitudinal direction is 0.3 mm, and the inner thickness of the spacer peripheral wall portion is 0.3 mm. The thickness of the spacer flat surface 1002 is 0.6 mm, which is the same as that of the spacer peripheral wall portion 301.

  This spacer 1000 is different from the spacer 400 (FIG. 11) in two points, that there is no bridging portion and that one end of the semicircular shape is a spacer flat surface 1002.

(Drop test)
The square sealed secondary battery produced above was subjected to a drop test to examine the degree of destruction of the gas discharge valve. Specifically, 10 square sealed secondary batteries of Examples 1 to 6 and Comparative Examples 1 to 5 were produced, respectively. Discharged until Next, with the positive electrode external terminal side of the battery facing downward, let it fall several times vertically onto the concrete surface from a height of 1.9 m, and repeat the number of drops until the gas discharge valve is destroyed (including cracks) Examined.

(Heating test)
Moreover, the heating test was done about the square sealed secondary battery produced above. Specifically, 10 square sealed secondary batteries of Examples 1 to 6 and Comparative Examples 1 to 5 were produced, respectively, and these batteries had a voltage of 4.2 V at a constant current of 1050 mA in an atmosphere of 25 ° C. And then stored in an atmosphere at 25 ° C. for 1 hour. Thereafter, the battery was placed on an iron plate heated to 250 ° C. for 10 minutes, and the number of batteries that had ruptured was counted. Smoke from the gas discharge valve and ignition, but those that did not rupture the battery were considered as no rupture.

  Table 1 shows the results of the drop test and the heat test.

  “Ave.” in Table 1 is the average number of times until the gas discharge valve is destroyed in all 10 units, “Min.” Is the minimum number of drops that the gas discharge valve has broken, and “Max.” Is the gas discharge valve is broken. It means the maximum number of times it has fallen. In addition, in the comprehensive judgment, the average number of drops exceeded 44.4 times (Comparative Example 4), and the case where no ignition was observed was “◎”, the average number of drops was less than 44.4 times, and ignition was recognized. The case where there was no fire was designated as “◯”, and the case where the average number of drops was 44.4 times or less and ignition was recognized was designated as “x”.

(Drop test result)
About Examples 1-6, the frequency | count of dropping until a gas exhaust valve was damaged thru | or destroyed increased significantly. It is clear that this effect is due to the roller provided with a bridging portion or a rib on the insulating plate or spacer.

  In the drop test, the space volume between the insulating plate and the electrode body is compressed by a drop impact force. Here, in the comparative example 3, the insulating plate 800 which does not have a through-hole in the insulating plate part directly under a gas exhaust valve is used. For this reason, the pressure which increased instantaneously by compression of the space volume by the drop impact force cannot be escaped promptly. For this reason, it is considered that the average number of drops (impact resistance) of Comparative Example 3 was significantly reduced.

  In the comparative example 4, the insulating plate 900 is used, and the insulating plate 900 has a through hole in the insulating plate portion directly under the gas discharge valve, but the portion has a flat surface without a peripheral wall portion. In the case of this structure, the gas pressure generated by the drop impact force can quickly escape upward, so it is considered that the average number of drops was larger than that of Comparative Example 3 (impact resistance was improved). Compared to the product of the example, it is considered that sufficient impact resistance could not be obtained because the relaxation effect of absorbing the impact force is reduced by the amount of the peripheral wall portion.

  Further, in Comparative Example 5, since the insulating plate portion immediately below the gas discharge valve and the corresponding portion of the spacer below the insulating plate 900 ′ and the spacer 1000 which do not have the peripheral wall portion, the impact resistance against the drop impact force is used. It is considered that the average number of times of dropping (impact resistance) is remarkably reduced because the pressure in the vicinity of the gas discharge valve generated by the drop impact force cannot be released.

  On the other hand, in Examples 1 to 6 in which a bridging portion or a rib is provided and an insulating plate or / and a spacer provided with a through hole or a spacer on the lower side of the gas discharge valve, the bridging portion or the rib has an impact force. It is considered that the average number of drops (impact resistance) is remarkably increased because the compression of the space volume due to the above is relaxed and the instantaneous increase in gas pressure is suppressed.

(Heating test result)
In Examples 1 to 6, the number of ruptured batteries was zero, and it was confirmed that the safety against heat was high. On the other hand, in Comparative Examples 3 to 5, particularly Comparative Example 3, battery rupture was observed.

 This result is considered as follows. In Comparative Example 3, it is considered that the gas generated on the electrode body side was not smoothly discharged from the gas discharge valve because the insulating plate 800 having no through hole was used on the lower side of the gas discharge valve. In Comparative Example 4, an insulating plate 900 having a flat surface without a peripheral wall portion directly under the gas discharge valve is used, and an insulating plate 900 having a through hole formed in the flat surface is used. The insulating plate 900 ′ and the spacer 1000, which are flat surfaces in which the corresponding portions of the lower spacer do not have any peripheral wall portions, are used, but these do not have a buffer space against the increase in gas pressure directly under the gas discharge valve. It is considered that the battery has ruptured due to its structure and lack of gas discharge capacity.

  On the other hand, in Comparative Examples 1 and 2, no battery rupture was observed. In Comparative Examples 1 and 2, an insulating plate and a spacer having through holes and slits as peripheral wall portions and gas passages are used. Because. In addition, the inner side of the peripheral wall portion is a depression, and this depression functions as a gas storage space that reduces an instantaneous increase in gas pressure. Therefore, it is considered that the presence of the peripheral wall portion reduces damage to the gas discharge valve due to impact force and battery rupture due to heating.

  According to the present invention, by adding a simple structure, it is possible to improve the impact resistance of the battery against external forces such as vibration force and drop impact force while keeping the sensitivity of the gas discharge valve appropriate. Therefore, it is possible to provide a rectangular sealed secondary battery with further improved safety and reliability against battery internal pressure and electrolyte leakage at low cost, and its industrial applicability is high.

101 Battery Can 102 Sealing Plate 103 Gas Discharge Valve 104 Electrode External Terminal 104 ′ Electrode External Terminal Mounting Hole 105 Pouring Port 106 Negative Electrode Plate 107 Positive Electrode Plate 108 Electrode Body

200 Insulating plate 201 Insulating plate peripheral wall portion 202 Insulating plate bridge portion 203 Through hole 204 Fastening hole 205 Convex portion

300, 400, 600, 1000 Spacer 301 Spacer peripheral wall portion 302 Spacer bridging portion 303, 305, 306 Slit 304 Recess 402 Spacer rib 603 Slit 1001 Spacer peripheral wall portion 1002 Spacer flat surface 1003 Slit


500, 700, 800, 900 Insulating plate 502 Insulating plate rib 901 Insulating plate peripheral wall 902 Insulating plate flat surface 903 Through hole

Claims (10)

A positive electrode plate having a positive electrode tab and a negative electrode plate having a negative electrode tab are wound through a separator and processed into a flat shape, and
A bottomed prismatic battery can containing the electrode body;
A sealing plate provided with a gas discharge valve for sealing the opening of the battery can;
An insulating spacer disposed above the electrode body housed in the battery can;
An insulating plate disposed between the spacer and the sealing plate;
With
In the rectangular sealed secondary battery in which the spacer and the insulating plate are arranged so as to cover the sealing plate side of the electrode body,
The insulating plate has a substantially rectangular shape with a through-hole through which gas can pass, and the insulating plate peripheral wall portion constituting the outer peripheral edge of the insulating plate has a height higher than its inner side, and the insulating plate In the straight part of the peripheral wall part, an insulating plate bridging part extending to the opposite side is formed,
A rectangular sealed secondary battery characterized by that. The square sealed secondary battery according to claim 1,
Instead of the insulating plate, it is a substantially rectangular shape with a through hole through which gas can pass, and the height of the insulating plate peripheral wall constituting the outer peripheral edge of the insulating plate is higher than the inside thereof, Insulation in which ribs extending from each of the pair of insulating plate peripheral wall portions to the front of the through hole are formed in the opposing straight portions of the insulating plate peripheral wall portion and in the portion where the through hole exists in the middle. Using a plate
A rectangular sealed secondary battery characterized by that. An electrode body in which a positive electrode plate having a positive electrode tab and a negative electrode plate having a negative electrode tab are wound through a separator and processed into a flat shape,
A bottomed prismatic battery can containing the electrode body;
A sealing plate provided with a gas discharge valve for sealing the opening of the battery can;
An insulating spacer disposed above the electrode body housed in the battery can;
An insulating plate disposed between the spacer and the sealing plate;
With
In the rectangular sealed secondary battery in which the spacer and the insulating plate are arranged so as to cover the sealing plate side of the electrode body,
The spacer has a substantially rectangular shape with a slit through which gas and a negative electrode tab can pass, and the spacer peripheral wall portion constituting the outer peripheral edge of the spacer has a height higher than the inside thereof, and the spacer In the linear part of the peripheral wall part, a bridging part extending to the opposite side is formed,
A rectangular sealed secondary battery characterized by that. The square sealed secondary battery according to claim 3,
Instead of the spacer, it has a substantially rectangular shape provided with a slit through which gas and a negative electrode tab can pass, and the height of the spacer peripheral wall portion constituting the outer peripheral edge of the spacer is higher than the inside thereof. Ribs extending from each of the pair of spacer peripheral wall portions to the front of the slit are formed in the straight portion of the spacer peripheral wall portion where the slit is located between the opposing spacer peripheral wall portions. Using the spacer that was made,
A rectangular sealed secondary battery characterized by that. The square sealed secondary battery according to claim 1,
The spacer has a substantially rectangular shape with a slit through which gas and a negative electrode tab can pass, and the spacer peripheral wall portion constituting the outer peripheral edge of the spacer has a height higher than the inside thereof, and the spacer In the linear part of the peripheral wall part, a bridging part extending to the opposite side is formed,
A rectangular sealed secondary battery characterized by that. The square sealed secondary battery according to claim 1,
The spacer has a substantially rectangular shape with a slit through which gas and a negative electrode tab can pass, and the height of the spacer peripheral wall portion constituting the outer peripheral edge of the spacer is higher than the inside thereof.
Ribs extending from each of the pair of spacer peripheral wall portions to the front of the slit are formed in the straight portion of the spacer peripheral wall portion where the slit is located between the opposing spacer peripheral wall portions. ,
A rectangular sealed secondary battery characterized by that. The square sealed secondary battery according to claim 2,
The spacer has a substantially rectangular shape with a slit through which gas and a negative electrode tab can pass, and the spacer peripheral wall portion constituting the outer peripheral edge of the spacer has a height higher than the inside thereof, and the spacer In the linear part of the peripheral wall part, a bridging part extending to the opposite side is formed,
A rectangular sealed secondary battery characterized by that. The square sealed secondary battery according to claim 2,
The spacer has a substantially rectangular shape with a slit through which gas and a negative electrode tab can pass, and the height of the spacer peripheral wall portion constituting the outer peripheral edge of the spacer is higher than the inside thereof.
Ribs extending from each of the pair of spacer peripheral wall portions to the front of the slit are formed in the straight portion of the spacer peripheral wall portion where the slit is located between the opposing spacer peripheral wall portions. ,
A rectangular sealed secondary battery characterized by that. The square sealed secondary battery according to any one of claims 1 to 8,
The insulating plate bridging portion and the spacer bridging portion are located not in the projection plane but in the vicinity of the projection plane when the gas discharge valve of the sealing plate is projected in the battery can axis direction.
A rectangular sealed secondary battery characterized by that. The square sealed secondary battery according to any one of claims 2 to 8,
The insulating plate rib and the spacer rib are located in or near the projection surface when the gas discharge valve of the sealing plate is projected in the battery can axial direction.
A rectangular sealed secondary battery characterized by that.

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