JP4534508B2 - Lead acid battery - Google Patents

Description

  The present invention relates to a monoblock lead-acid battery connected between cells via a cell partition wall of a battery case.

  The lead acid battery is a battery that uses lead dioxide as a positive electrode active material, metal lead as a negative electrode active material, and dilute sulfuric acid as an electrolyte. In general, lead-acid batteries form an electrode plate group by laminating an arbitrary number of positive and negative electrodes through a porous and insulating separator, and these are housed in a battery case to form a cell and inject dilute sulfuric acid. Configured. As a form of the battery, a liquid type structure using abundant amount of electrolyte has historically been used for a long time. However, recently, a mat-like material such as a glass mat is used for the separator, and the amount of electrolyte is supplied to the separator. Sealed batteries that allow gas absorption while limiting to a level that can almost be absorbed have been developed and put into practical use.

  With the many improvements, the sealed battery has been reviewed for its safety and characteristics due to sealing, and has responded to the demands of a new era such as electric vehicles and forklifts as well as those for starting automobiles that have been developed mainly for liquid type. New demand is also expanding for mobile power applications.

  In the mobile power application, the battery is mounted in a limited space, and the mounting energy is important because the amount of mounted energy determines the function of the device. Reliability with respect to battery and vibration characteristics is regarded as important.

  By the way, a lead-acid battery has a cell voltage as low as about 2V in principle, and its use in a single cell is rare. Therefore, regardless of the form and use of the battery, in general, a plurality of cells are gathered, connected between cells in series or in parallel as necessary, a predetermined voltage and capacity are formed, and an integrated monoblock structure is formed. It is common to form and use.

  In the monoblock structure, it is necessary to form an appropriate electrical connection between cells and to form an airtight or liquid-tight configuration between cells while considering mounting efficiency.

  If the airtight or liquid tight function is insufficient, the gas generated during charging will move between cells, the electrolyte will move substantially due to the gas absorption reaction, and the amount of electrolyte will become uneven, resulting in variations in characteristics. In addition, it is known that when the electrolyte is in liquid junction between the cells, self-discharge proceeds and the characteristics deteriorate. Therefore, the monoblock structure basically requires an air-tight or liquid-tight separation function between cells as well as electrical connection between cells.

  However, in the conventional applications such as electric vehicles and forklifts that are subject to shocks and vibrations, the reliability of the airtight or liquid-tight function of the monoblock structure is not always sufficient, and it is especially designed with the mounting efficiency in mind. In addition, in a battery having a monoblock structure, the airtight or liquid tight structure of the inter-cell connection portion is likely to be damaged, and the battery function characteristics may be deteriorated or varied.

  Conventionally, in the battery of a monoblock structure, the following configurations have been mainly applied to the formation of the cell-to-cell connection and the airtight or liquid tight function.

For example, in a configuration using a PP (polypropylene) resin battery case, which is known as the most common monoblock battery configuration, a battery case having a through-hole in a partition wall between cells, and an electrode plate group of each cell A strap that electrically collects the same polarity electrode plates and an inter-cell connecting body projecting upward from the shelf of the strap, and the inter-cell connecting body faces the electrode plate group through a through-hole. The electrode plate group is inserted into the battery case in such a manner that the gas-tight or liquid-tight connection is made using the resistance welding between the connecting bodies through the through-hole.

  Further, between the upper end of the partition wall and the lower part of the lid, the welding margin provided at the joint is melted by a hot plate to be heat-sealed in an airtight or liquid-tight manner. By the above, an electrical connection between cells and an airtight or liquidtight separation structure between cells are formed.

  In addition to the above, many techniques have been developed in which projections of various shapes that pass through the through hole are formed on a part of the connection body and welding is performed using these.

  Regardless of the connection state of the connection body, the above-described configuration allows the flat plate portion around the welded portion to be in close contact with the partition wall while utilizing the strong clamping force of the welded structure formed for electrical connection between cells. The structure is based on packing around the through hole in an airtight or liquid tight manner.

  That is, in the said structure, the space on a strap for welding operation | work and the height of the connection body for forming a plane part area in packing are needed, and formation of the space of at least several tens mm from a strap height is forced. The space is a design element which becomes a dead space for battery electromotive reaction and is not preferable for battery energy or mounting efficiency.

  In addition to the connection method through the through-hole, as a structural example of a monoblock battery using, for example, an ABS (acrylonitrile butadiene styrene) resin battery case, a cell protruding on the partition wall on the strap Forming an inter-connection part, completing the connection using a gas burner or the like, and inserting the electrode plate group formed with the inter-cell connection into the battery case so that the weld part fits into the partition wall, and further, the joint part In addition, there is known a method in which a monoblock structure is configured by inversion installation on the back surface of a lid provided with a recess for storing the upper end of the partition wall, and injecting resin into the recess and curing.

  However, these methods not only have a problem in the impact resistance of the resin welded portion, but also need to provide a large protrusion on the upper portion of the strap, and the formation of a dead space cannot be avoided.

  From the above viewpoint, instead of a configuration in which the connection body protrudes from the upper part of the strap, some configurations have been tried in which the inter-cell connection body does not protrude at least largely and the straps are connected substantially linearly.

  For example, in Patent Document 1, a bridge is welded to a conductor bridge extending in a horizontal direction from adjacent strap shelves of cells, the bridge is arranged in a recess of a partition wall, and the periphery of the bridge is A configuration is disclosed in which it is covered with resin and installed between the upper end of the partition wall and the lid.

  Further, Patent Document 2 discloses a configuration in which a connection body having a height substantially the same as the height of the strap is configured, and a thermosetting resin is disposed on a peripheral portion where the inter-cell connection body contacts the partition wall to be bonded or sealed. Has been.

Further, Patent Document 3 discloses a configuration in which the connection body is protruded in a horizontal space instead of the upper part, the cells are connected to each other, and the connection body is fitted into a recess provided in the partition wall. All of these techniques disclose a configuration that reduces dead space in the height direction.
Japanese Utility Model Publication No. 41-19585 JP 9-31154 A JP 2001-266835 A

  However, on the other hand, the thickness of contact between the connecting body and the partition wall is extremely small, and the binding force between the resin and the metal is particularly insufficient, and it is easy to peel off against severe vibrations such as electric vehicles and forklifts. Or it was difficult to maintain high reliability against liquid tightness.

  In other words, the monoblock battery having the above-described structure is subjected to a severe impact and damages the airtight or liquidtight separation function between the inter-cell junction and the cell with which they abut, thereby causing variations in electrolyte amount and liquid junction. As a result, there is a risk of causing defects in battery characteristics.

  That is, an object of the present invention is to establish a battery having a monoblock structure that can achieve both high mounting efficiency and high reliability of airtight or liquid-tight function against vibration.

As a specific means for solving the above problems, the present invention includes an electrode plate group, a battery case having cell partition walls, an inter-cell connection body that connects between electrode plate groups of adjacent cells, and a lid body. In the lead-acid battery, a recess is formed in the upper part of the partition wall between the cells, the inter-cell connector is fitted into the recess, and the inter-cell connector is in contact with the recess and the lid. The lead acid battery provided with the elastic coating body arrange | positioned so that the outer periphery of this may be enclosed is disclosed.

  As described above, the present invention establishes the reliability of the airtight or liquid-tight function at the position where the inter-cell connecting body penetrates the cell partition wall, and achieves both mounting efficiency and impact resistance characteristics, It has the effect of increasing the applicability of lead-acid batteries to fields of use demanded by society such as automobiles and forklifts.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

  FIG. 1, FIG. 2 and FIG. 3 show an embodiment showing a battery configuration of the monoblock structure of the present invention. FIG. 1 is a sectional view of the monoblock battery as viewed from the short side, and FIG. FIG. 3 is a cross-sectional view of the monoblock battery viewed from the long side, and FIG. 3 is a top perspective view of the monoblock battery structure before welding the battery lid of the present invention. FIG. 4 is a cross-sectional view of a monoblock battery as viewed from the short side surface showing the inter-cell connection portion of the conventional lead storage battery, and FIG. 5 is a cross-sectional view of the monoblock battery as viewed from the long side face of the conventional lead storage battery.

  In each figure, an electrode plate group 5 consisting of a positive electrode plate, a negative electrode plate, and a glass mat separator is accommodated in a battery container consisting of a battery case 1 having a cell partition wall 2 provided with a recess and a lid body 4, and the electrode plate The group 5 is connected to the external terminal 7 via electrode plate terminals 6 and 6 'having different polarities.

  Moreover, it has the same cross-sectional shape as the battery strap, and surrounds the outer periphery of the inter-cell connection body 8 at a position corresponding to the cell partition wall 2 at least in the horizontal direction formed in the long side direction of the battery. The elastic covering body 9 is press-fitted into a concave portion provided on the partition wall together with the inter-cell connection body.

  In addition, for the formation of the elastic covering 9, any method such as sandwiching and welding the inter-cell connecting body in the block forming the elastic covering 9 can be applied, but a mold is disposed at a predetermined place, It is preferable to perform injection molding in order to obtain close contact force and outer shape forming accuracy.

  In addition, the first method of welding the straps of the electrode plate groups of each cell using a burner or resistance welding using the inter-cell connection body provided with the elastic covering, and temporarily inserting the electrode plate groups into the battery case A second method of simultaneously completing strap formation and inter-cell connection by a cast-on-strap method using an inter-cell connection body provided with an elastic covering, and temporarily inserting a plate group into a battery case, and a cast-on-strap method The strap formation, the formation of the inter-cell connection body and the connection structure are simultaneously formed, and the third method of injecting the elastic cover using a mold at a predetermined position of the inter-cell connection body can be applied. is there.

  Among them, the third method is the simplest, highly accurate and preferable method in forming the strap, the inter-cell connection body, and the inter-cell connection portion.

  In any of the above methods, after the connection is completed, the battery case is returned to the normal position, the electrode plate group connected between the cells is inserted inside the battery case, and the inter-cell connection body in which the elastic covering is formed is It is press-fitted into the cell partition wall recess of the battery case. Further, a welding block provided on the upper surface of the battery case and the back surface of the lid is thermally welded to complete a monoblock structure battery.

  In the above-described configuration, the elastic cover 9 and the partition wall are pressure-tightly sealed in an airtight or liquid-tight manner by press fitting into the partition wall recess of the inter-cell connection body in which the elastic cover 9 is disposed.

  In order to form an airtight or liquid-tight function by the press fitting, it is preferable that the outer peripheral dimension of the elastic covering is formed larger in the vertical and horizontal directions than the internal dimension of the cell partition wall recess. The dimensional relationship varies depending on the elasticity of the elastic cover, but is pressurized and sealed in an airtight or liquid-tight manner by the elasticity of the elastic cover that is press-fitted. Moreover, conditions that require a pressure of 10 kPa to 40 kPa are preferable.

  The pressure applied between the elastic cover 9 and the bottom and side surfaces of the cell partition wall recess and between the elastic cover 9 and the bottom surface of the lid 4 press-fitted is maintained by the fixing force of the welded resin. Is sealed by being hermetically or liquid tightly pressure-bonded to the lower surface of the lid.

  For the elastic covering 9, foamed resin having closed cells is a preferable material for maintaining deformation and elasticity due to strength, and foamed ethylene propylene rubber and foamed chloroprene rubber can be used as the foamed resin.

  As described above, since the airtight or liquid tight function of the present invention is formed by press fitting of the elastic covering provided in the inter-cell connecting body, at least one of the shape of the recess between the cell partition walls and the outer shape of the elastic covering is provided. It is preferable to provide an arbitrary taper to facilitate press-fitting.

  In the above configuration, the lower surface of the lid and the upper surface of the elastic covering do not necessarily have to be welded. However, in the configuration in which this portion is welded, not only the sealing reliability of the welded portion is increased, but also the thickness of the elastic covering is increased. There is an effect of suppressing movement, which is preferable.

  In this configuration, the airtight or liquid-tight function between the elastic cover 9 and the inter-cell connector 8 depends on the elasticity of the elastic cover 9 press-fitted into the through hole surrounded by the partition wall recess and the lid. It is formed by pressure contact force. Therefore, an adhesive force between the elastic covering 9 and the inter-cell connection body 8 is not necessarily required, but it is arbitrary that the elastic covering 9 is bound at the time of formation.

  Further, it is optional to reinforce the elastic covering body 9 and the partition wall wall surface and the exposed interface between the elastic covering body 9 and the inter-cell connection body 8 using an adhesive resin or a thermosetting resin.

  As described above, the present invention does not form a dead space by projecting a connection body upward from the strap shelf position, and is excellent in airtightness against severe vibrations even at a penetration distance of a partition wall with a small thickness. It is possible to form a monoblock lead-acid battery having liquid-tight reliability.

The configuration and effects of the present invention will be described below with reference to examples.
Example 1
The electrode plate group 5 including a positive electrode plate, a negative electrode plate, and a glass retainer mat, a battery case 1 made of polypropylene resin and provided with a concave portion penetrating the inter-cell connecting body 8 at the upper end of the inter-cell partition wall, and welded to the upper part of the battery case. The lid 4 was prepared, and using these, 12V40Ah in which 6 cells were connected in series with the structure as shown in FIGS. 1, 2 and 3, the outer size was 150 mm in height, the battery length was 300 mm, A battery having a monoblock structure with a battery width of 100 mm was produced.

  In order to form a battery having a monoblock structure, first, the electrode plate group was temporarily inserted into the battery case and turned upside down, and the formation of the strap and inter-cell connection body and the connection structure were simultaneously formed by the cast-on strap method. As shown in FIG. 3, the inter-cell connection body has the same thickness as the strap shelf, and is formed in the horizontal direction from the strap to the adjacent strap at the same height as the shelf upper surface.

  Next, the outer periphery was surrounded by using a mold at a predetermined position of the inter-cell connector, and an elastic covering having a thickness of 2 mm was formed by injection. The elastic coating layer was set to a position of 5 mm on both sides from the partition wall surface. Foamed ethylene propylene rubber was used for the elastic body.

After the above operation, the entire battery case was returned to the normal position, and the electrode plate group was press-fitted. The inter-cell connection body and the elastic covering body portion were inserted and fitted into the concave portion of the partition wall using a pressure of 10 kPa. Moreover, the lid | cover provided with an external terminal heat-welded the welding margin provided in the back surface of the lid body, and the welding margin provided in the battery case upper surface. The battery thus manufactured is referred to as a battery A.
(Comparative Example 1)
Using the same electrode plate group as in Example 1, a battery having a monoblock structure was produced by the following method. In the electrode plate group, a connecting body portion protruding by a height of 30 mm was formed on the upper part of the strap shelf. Moreover, the battery case which made the height of the partition wall 30 mm higher than the battery case of Example 1 was shape | molded, the 10 mm diameter through-hole was provided in the position of 10 mm from the upper end of the said partition wall, and the said connection body was set in the position of a through-hole. An electrode plate group was inserted. The inter-cell connector was pressurized from both sides and resistance welded using convex terminals. Next, the welding margin provided on the upper end of the partition wall and the back surface of the lid body is heated by thermal welding, and these are welded. As shown in FIGS. 4 and 5, the external size is 180 mm in height, the battery A battery having a monoblock structure with a length of 300 mm and a battery width of 100 mm was produced as a battery B.
(Comparative Example 2)
Monoblock structure as in Example 1, except that an elastic covering is not used and a thermosetting resin is provided between the inter-cell connection body and the recess and the back surface of the lid to form an airtight or liquid tight function. A battery was prepared. The battery produced was 12V40Ah, size 180 mm, battery length 300 mm, battery width 100, and was designated as battery C.

  Each of the above-mentioned monoblock structure batteries was given a 1G vertical impact for 10 hours in a cycle of 10 times per minute, and then the airtightness between the cells was examined by attaching a pressurized air port to each cell. The probability of occurrence of a battery with impaired function was determined.

  Further, for each battery, the discharge capacity at 0.25 CA was obtained with respect to the nominal capacity CAh after being left for one week, and the probability of occurrence of a battery that could not maintain 80% of the capacity before being left was determined.

The results obtained by the above test are shown in Table 1 together with the mounting efficiency (energy density per volume).

表１から明らかなように、搭載効率は、本発明の構成の電池Ａでは１０７Ｗｈ／ｌ、電池Ｂでは８６Ｗｈ／ｌ、電池Ｃでは１０５Ｗｈ／ｌであり、電池Ｂでは電池Ａに比べて８３％、電池Ｃではほぼ同等の搭載効率であった。

As is apparent from Table 1, the mounting efficiency is 107 Wh / l for battery A having the configuration of the present invention, 86 Wh / l for battery B, 105 Wh / l for battery C, and 83% for battery B compared to battery A. Battery C had almost the same mounting efficiency.

  The decrease in the mounting efficiency in the battery B was not due to the difference in battery characteristics that was substantially obtained, but was due to an increase in dead space resulting from the need for a connection structure that stood above the strap.

  Next, the failure occurrence probability in the airtight reliability test against shock vibration was 0% for battery A, 20% for battery B, and 10% for battery C. As a result, in the structure in which the cell indirect side body is leveled and the contact distance of the portion where the inter-cell connecting body passes through the partition wall is small, the contact portion is fixed and sealed with the solidifying resin. Then, it was shown that the reliability of the airtight or liquid tight function cannot be expected at all with respect to vibration and impact. That is, with these configurations, it is considered difficult to achieve both mounting efficiency design by adopting a low-order cell connection structure and impact resistance.

  On the other hand, in the battery A having a configuration in which an elastic cover is formed on the outer periphery of the inter-cell connection body in the partition wall recess of the inter-cell connection body of the present invention, and the elastic cover is inserted and fitted into the partition wall recess, It shows that high reliability can be given to the airtight or liquid tight function against vibration and vibration.

  In addition, the probability of occurrence of the characteristically deteriorated battery after leaving the impact test was 0% for A, 10% for B, and 10% for C. The result shows that the probability of occurrence of a deteriorated battery shows a value similar in tendency to the probability of occurrence of a battery with poor airtightness, and the above result is considered to be due to a deterioration in characteristics resulting from airtightness failure caused by vibration or impact.

  Furthermore, when the above-mentioned deteriorated battery is disassembled, there is no abnormality in the electrode plate powder and electrical connection, but cracks and breakage are seen in the sealing part of the partition wall, and these monoblock battery cells In the meantime, variations in electrolyte volume and capacity were observed.

  As described above, the present invention not only reduces the dead space required in connection with the connection between cells and enables the design of a monoblock battery with high mounting efficiency, but also with the lowering of the connection between cells. This improves the reliability of the airtight or liquid-tight function that accompanies the impact that should be taken into consideration, and achieves both substantial impact resistance and high mounting efficiency.

  The present invention is intended to improve the reliability of the air-tight or liquid-tight function of the portion where the inter-cell connection body of the battery of the monoblock structure exposed to impact penetrates the partition wall between the cells. It can be applied regardless of the battery configuration. Moreover, it is effective regardless of the position in the height direction from the strap of the inter-cell connection body, and is not limited to the configuration disclosed in the embodiments.

  It is possible to achieve both high impact resistance and mounting efficiency, and is useful as a power source for mobile vehicles such as electric vehicles and forklifts.

1 is a short side cross-sectional view of a battery according to an embodiment of the present invention. 1 is a cross-sectional side view of a battery according to an embodiment of the present invention. The perspective view of the battery of one Example of this invention. Short side view of a conventional battery Long side cross-sectional view of a conventional battery

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Battery case 2 Cell partition wall 4 Lid body 5 Electrode board group 6 Electrode board terminal 7 External terminal 8 Connection between cells 9 Elastic covering body

Claims (5)

In a lead storage battery having an electrode plate group, a battery case having a cell partition wall, an inter-cell connection body connecting between electrode plate groups of adjacent cells, and a lid,
A recess is formed in the upper part of the cell partition wall,
The inter-cell connector is fitted into the recess,
The lead acid battery in which the elastic covering body arrange | positioned so that the outer periphery of the connection body between cells may be enclosed in the part which the said connection body between cells contact | abuts with the said recessed part and the said cover body. The lead storage battery according to claim 1, wherein the elastic covering body is brought into a pressure contact state at least by the concave portion or the lid body. The lead acid battery according to claim 1 or 2, wherein the battery case and the lid are thermally welded, and the elastic body and a part of the lid are thermally welded. The lead storage battery according to any one of claims 1 to 3, wherein the elastic covering is a foamed resin. The lead acid battery according to any one of claims 1 to 4, wherein the elastic covering body continuously surrounds an outer peripheral surface of the inter-cell connector.

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