Patent Document

FIELD OF THE INVENTION 
       [0001]    The invention relates to assemblies for the storage of electrical energy. It applies, in particular, but not in a limited way, to supercapacitors, capacitors, and generators or batteries. More precisely, the present invention relates to the sealing and the electrical connection of an assembly for the storage of electrical energy. 
       PRESENTATION OF THE PRIOR ART 
       [0002]    A large number of electrical energy storage assemblies, so-called of the high-power type, have recently been proposed, such as supercapacitors for example. 
         [0003]    However, the known devices are not totally satisfactory in terms of their sealing and their power connections. 
         [0004]    Conventionally, a supercapacitor includes a coiled element composed of a stack of leaves or sheets (anode, collector, anode, separator, cathode, collector, cathode, separator) wound onto itself, with one of these leaves projecting at each end, known as a current collector. This coiled element is placed in an envelope that includes a main body that is closed off at least at one of its two ends by a lid. 
         [0005]    According to the prior art, in order to create such an electrical energy storage system, the lid is attached to the main body of the envelope by a mechanical assembly, by crimping, bolting or rolling, for example (turning back the edge of the main body onto the lid to compress a sealing gasket provided between the two). 
         [0006]    In addition, mention will also be made of the regular use of electrical connection elements in order to create the electrical connection, within the main body of the envelope, between each lid equipped with an electrical connection terminal and the coiled element. 
         [0007]    As the electrical connection element, some designs use the current collector projecting from the coiled element and cut to form one or more stacks of current collecting tabs, with these tabs then being connected to the electrical connection terminal of the lid. 
         [0008]    However, these embodiments are complex and lead to very bulky electrical energy storage assemblies. 
         [0009]    Furthermore, the current is not distributed uniformly in the coiled element due to the fact that all the turns are not connected to the electrical connection terminal. This characteristic encourages concentrations of ions and electrons in some turns to the detriment of others, thus leading to:
       an increase in the series resistance, which has negative effects on the performance of the energy storage element (reduction in the energy and the power available),   heating which is favoured by poor removal of the internal heat by the current collectors, and   localisation or even acceleration of ageing in the energy storage element.       
 
         [0013]    Other embodiments therefore propose welding, by a transparency laser technique, of an intermediate electrical connecting part provided between the coiled element and each of the lids. 
         [0014]    However, these designs are complex, because of a large increase in the operations to be performed. Moreover, the presence of this intermediate part complicates the design of the electrical energy storage system in terms of mass. 
         [0015]    It is possible to also mention a design for an electrical energy storage system in which the coiled element is directly flattened and welded against the lids in order to optimise the volume of the whole. 
         [0016]    In this case however, the mechanical closures of the lids prevent the weld zones present on the lids to come into contact with all the turns of the coiled element and then also limit the quantity of welded turns. 
         [0017]    Furthermore, all these embodiments of supercapacitors have as a common feature that they possess sealing faults. 
         [0018]    In fact, the ageing of these assemblies of the supercapacitor type lead to the generation of gas in the envelope of the electrical energy storage element that results in a rise in the pressure within the envelope. 
         [0019]    The conventional closures by rolling or by bolting of the lids onto the main body of the envelope are not designed to resist this pressure increase and give rise to a loss of sealing in the electrical energy storage system, sometimes resulting in leakages of solvent, or even in the worst cases, in abrupt rupture. 
         [0020]    In addition, at the present time, during their mounting in a module, these mechanical electrical energy storage assemblies require the addition of an electrical connection element between each pair of neighbouring assemblies with a view to connecting them electrically. 
         [0021]    In some designs, these parts, of the rigid or flexible strap, braid or stack of sheets type, are screwed onto each of the respective electrical connection terminals of a pair of electrical energy storage assemblies. 
         [0022]    These module designs often require costly treatment of the parts, such as tin or nickel plating, in order to ensure optimal electrical contact when bolted. 
         [0023]    Other embodiments include the welding of these parts. But the temperature rises created by the welding often limit its execution on non-finished elements and lead most of the time to the assembly of modules before the electrolyte filling step, which greatly complicates the production method. 
         [0024]    The creation of these module assemblies by the addition of connector parts is lengthy and complex. 
         [0025]    The aim of the invention is particularly to overcome the drawbacks of the prior art. 
         [0026]    Another aim of the present invention is to propose a system for the electrical energy storage having a configuration that is easy to perform, while also offering simple and secure electrical connection. 
         [0027]    Another aim of the present invention is to propose a system for the electrical energy storage having a sealing system which is reliable over time, resistant to very high internal pressures, and whose adjustable sealing performance can cope with values below 10 −9  mbar.l.s −1 . 
         [0028]    It is also desirable to propose systems for the electrical energy storage that offer a saving in terms of cost, weight, space, and production time. 
         [0029]    Another aim of the present invention is to propose a system for the electrical energy storage that facilitates its association with other similar systems so as to form an electrical energy storage module. 
       SUMMARY OF THE INVENTION 
       [0030]    These aims are attained, according to the invention, by virtue of a system for the electrical energy storage including at least one coiled electrical energy storage element placed within an envelope, the said envelope enclosing the coiled electrical energy storage element in a main body of the envelope, and including at least one lid, characterised in that the said lid, placed at one end of the main body of the envelope and connected electrically by electrical link means to the coiled electrical energy storage element, is attached to the main body of the envelope by bonding means. 
         [0031]    According to another advantageous characteristic of the invention, the bonding element is placed so as to cover a positioning gasket inserted between the main body of the envelope and the lid. 
         [0032]    According to another advantageous characteristic of the invention, the positioning gasket and the bonding element are provided in an annular channel formed by the main body of the envelope and a small collar present on the said lid. 
         [0033]    According to another advantageous characteristic of the invention, at least two electrical energy storage systems according to the invention form an electrical energy storage module by using a single electrically conducting part with two or more lids, made from various materials or attached by assembly, which respectively enclose spooled elements for the storage of electrical energy provided in juxtaposed main envelope bodies. 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         [0034]    The invention will be understood more clearly, and other advantages and characteristics will appear, on reading the description that follows, and which is given by way of non-limiting examples, and by means of the appended drawings in which: 
           [0035]      FIG. 1  illustrates a view in longitudinal section of a system for the storage of electrical energy according to the invention; 
           [0036]      FIG. 1   a  represents a similar view in section of a variant whose lids have a double small collar; 
           [0037]      FIG. 1   b  represents a view in longitudinal section of another variant whose main envelope body forms double small collars in order to hold the lids; 
           [0038]      FIG. 2  illustrates a view in longitudinal section of another variant of  FIG. 1 ; 
           [0039]      FIG. 3  illustrates a view in perspective of the top of a lid of a system for the storage of electrical energy according to the invention; 
           [0040]      FIG. 4  illustrates a view in perspective of the bottom of a lid of a system for the storage of electrical energy according to the invention; 
           [0041]      FIG. 5   a  illustrates a top view of a lid of an electrical energy storage system according to the invention equipped with electrical connection means, while  FIG. 5   b  illustrates the same lid according to a longitudinal section passing through the half-sectional planes referenced V-V in  FIG. 5   a;    
           [0042]      FIG. 6   a  illustrates a top view of a variant of the lid of an electrical energy storage system according to the invention, equipped with electrical connection means, while  FIG. 6   b  illustrates the same lid according to a longitudinal section passing through the half-sectional planes referenced VI-VI in  FIG. 6   a;    
           [0043]      FIG. 7   a  illustrates a top view of another variant of the lid of an electrical energy storage system according to the invention, equipped with electrical connection means, while  FIG. 7   b  illustrates the same lid according to a longitudinal section passing through the half-sectional planes referenced VII-VII in  FIG. 7   a;    
           [0044]      FIG. 8  illustrates a top view of a lid according to another variant of the invention; 
           [0045]      FIG. 9  illustrates a view in longitudinal section of a small connecting strap according to the invention; 
           [0046]      FIGS. 10   a  and  10   b  illustrate, in longitudinal section, an embodiment variant of an electrical energy storage system according to the present invention, in which the main envelope body is equipped with an expansion bellows, respectively in the rest position in  FIG. 10   a  and after extension of the bellows in  FIG. 10   b;    
           [0047]      FIGS. 11   a ,  11   b ,  11   c  and  11   d  illustrate views in section of four variants of positioning gaskets; 
           [0048]      FIG. 12  shows a block diagram of the different steps of a method for the embodiment of an electrical energy storage system according to the invention; 
           [0049]      FIG. 13  illustrates a view in longitudinal section of an electrical energy storage module according to the invention created using two systems combined; 
           [0050]      FIG. 14  illustrates a top view of the twin-lidded part of an electrical energy storage module according to the invention; 
           [0051]      FIGS. 15   a  and  15   b  respectively show a top view and a side view of an electrical energy storage module according to the invention, created using a larger number of associated systems; and 
           [0052]      FIG. 16  shows a view in longitudinal section of a variant of the system for the storage of energy according to the invention, which includes a central tubular canal allowing the passage of a heat-bearing fluid for use in thermal regulation of the system. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0053]      FIG. 1  illustrates an electrical energy storage system  100  according to the invention. 
         [0054]    An electrical energy storage system  100  includes an envelope  200  formed of a main body  210  receiving a coiled electrical energy storage element, and of two lids  230  and  240  closing off the main body  210  of the envelope  200  at its two ends. It also includes, on the lids  230  and  240 , electrical connection means  280  (see  FIG. 3 ) intended to provide an electrical link between the lids  230 ,  240  and the said coiled element. 
         [0055]    The main body  210  of the envelope  200  comes in the form of a cylinder  211 , open at its two ends  212  and  213  and centred on axis X-X. 
         [0056]    This cylinder  211  is advantageously rigid and light. 
         [0057]    It is preferably made of aluminium, and its thickness is between 0.4 and 1 mm. 
         [0058]    According to an embodiment variant of the electrical energy storage system, the cylinder  211  is in a plastic material. 
         [0059]    Furthermore, this cylinder  211  has an internal diameter and a length to suit the coiled electrical energy storage element that it contains. 
         [0060]    However, an embodiment variant provides for a cylinder length  211  that is smaller than that of the coiled electrical energy storage element, so as to put the latter under pressure during the closure of the main body  210  of the envelope  200  by the two lids  230  and  240 . 
         [0061]    The coiled element placed in the main body  210  of the envelope  200  can be the subject of many embodiment variants. It will therefore not be described in detail in what follows. Neither is it illustrated in detail in the appended figures. However it is represented in  FIG. 1  under the reference  700 . 
         [0062]    In one embodiment of the invention, the coiled electrical energy storage element is a cylindrical roll centred on axis X-X. 
         [0063]    It is formed, in a manner which itself is familiar, of a stack of leaves or sheets (anode, collector, anode, separator, cathode, collector, cathode, separator) wound around a central axis that coincides, after assembly, with axis X-X, with or without the presence of a solid central support and in which one of the leaves comprising the stack, called the current collector, projects at each end. 
         [0064]    In fact, the coiled electrical energy storage element is bordered respectively at both of its opposite ends by two current collecting elements, in spiral form. 
         [0065]    The latter are intended to be connected to the electrical connection means  280  of the two lids  230  and  240  that cover them, as will be described later in relation to  FIGS. 3 to 9  in particular. 
         [0066]    In addition, the two electrically conducting lids  230  and  240  each respectively come in the form of an electrical connection disk  231  and  241 , placed perpendicularly to axis X-X. 
         [0067]    Each of these disks  231  and  241  includes, respectively, along its outer periphery, a small collar  232 ,  242 , formed of a cylindrical skirt centred on axis X-X. 
         [0068]    Each of the lids  230 ,  240  is preferably rigid and made of aluminium. 
         [0069]    The thickness of each of the electrical connection disks  231  and  241  is designed, in a manner which itself is familiar, to provide a section for the passage of current that is sufficient as a function of the radius of the disks  231  and  241 . 
         [0070]    Furthermore, in the embodiment variant of the invention of  FIG. 1 , the external diameter of each of the electrical connection disks  231  and  241  is greater than the external diameter of the cylinder  211   
         [0071]    Thus, the small collars  232  and  242  are placed on the outside of the external wall of the cylinder  211 . As a result, the latter and the internal wall of each of the small collars  232  and  242  of the lids  230  and  240  placed on the opposite ends  212  and  213  of the cylinder  211  respectively form two annular channels  236  and  246 , outside the main body of the envelope  200 . 
         [0072]    In a preferred embodiment of the invention, in order to position and fix each of the lids  230  and  240  to the two ends  212  and  213  of the cylinder  211 , use is made of a system that basically includes a positioning gasket  500  and a bonding element  600 . 
         [0073]    In the embodiment variant illustrated in  FIG. 1 , two annular positioning gaskets  510  and  520 , are fitted tightly on the cylinder  211  at its two ends  212  and  213  and, more precisely, in the annular channels  236  and  246 . 
         [0074]    These gaskets  510  and  520  have as their primary role to provide the electrical insulation between the main body  210  of the envelope  200  housing the coiled electrical energy storage element and each of the two lids  230  and  240 . 
         [0075]    Thus they are preferably made of an electrically non-conducting material, of the polytetrafluoroethylene (PTFE) type for example, glass loaded or not, or of plastic, of the polyphenylene Ryton® type. 
         [0076]    The second role of the gaskets  510  and  520  is that of support for the bonding element  600 , before and during its curing process, preventing the latter from running into the cylinder  211  in order to avoid damaging the coiled electrical energy storage element. 
         [0077]    Thus, as illustrated in  FIG. 11   a , the positioning gaskets  510  and  520  can be of rectangular cross section. 
         [0078]    However, as illustrated in  FIGS. 11   b ,  11   c  and  11   d , the positioning gaskets  510  and  520  can be the subject of many embodiment variants with, for example, cross sections that are respectively circular ( FIG. 11   b ), L-shaped with the inside of the L facing generally and radially inwards, that is toward the main body  211  of the envelope  200  ( FIG. 11   c ) or vice versa ( FIG. 11   d ). 
         [0079]    The positioning gaskets  510  and  520  are thus covered, respectively, in the annular channels  236  and  246  by a bonding element  610  and  620  in order to affix the main body  211  of the envelope  200  to each of the lids  230  and  240 . By “covered” is meant, in the context of the present description, the fact that the bonding element  610  and  620  are placed on the outside of the positioning gaskets  510  and  520  in relation to the conducting path of the internal volume of the cylinder  211 , on the outside of the latter, passing through the passage formed between the cylinder  211  and the lids  230  and  240 . 
         [0080]    The height, considered parallel to axis X-X, of the bonding element  610  and  620  deposited over all the circumference of the annular channels  236  and  246 , in contact with each of the lids  230  and  240  and the cylinder  211 , is adapted so as not to project beyond the height of each of the small collars  232  and  242  of the lids  230  and  240 . 
         [0081]    Furthermore, the adjustable height of the bonding element  610  and  620  provides a variable seal for the electrical energy storage system  100 . In fact, a large bonding height increases the strength of the system  100  in relation to the high internal pressure of the main body  211  of the envelope  200  and resists the opening of the envelope  200  under the effect of this pressure. 
         [0082]    Typically, the seal achieved by the bonding element according to the present invention, between the cylinder  211  and the lids  230  and  240  of a supercapacitor, can attain very low values, even below 10 −9  mbar.l.s −1 . These values are very clearly below those commonly encountered with the commercially available products. This excellent level of seal achieved by bonding prevent the penetration of oxygen or of water into the supercapacitor, the result of which would be acceleration of the ageing process and therefore a reduction of the life expectancy of the product. 
         [0083]    Advantageously, these bonding elements  610  and  620  are an adhesive compound that is both gas and water proof, and electrically insulating, of the heat-cured epoxy type. 
         [0084]    The latter is preferably suitable for the fixing of aluminium to aluminium, such as, the DELO Monopox  1196  adhesive from DELO for example. 
         [0085]    In an embodiment variant of the invention in which the cylinder  211  is in plastic, the adhesive will be specific to plastic/aluminium bonding. 
         [0086]    Furthermore, each positioning gasket  510  and  520  must be resistant to the curing temperature of the adhesive used, as well as to any solvent that will be used in the coiled electrical energy storage element. 
         [0087]    The positioning gaskets  510  and  520  also advantageously have an external surface that is sufficiently smooth to provide the two lids  230  and  240  with a slight latitude of movement in relation to the cylinder  211 , in order to allow easy installation of the latter on the cylinder  211 . 
         [0088]    This latitude of movement is used to provide some play which allows pressurisation to be applied during the electrical connection of the coiled electrical energy storage element to the lids  230  and  240 , as will be described later in relation to  FIGS. 3 to 8 . 
         [0089]      FIG. 2  illustrates an embodiment variant of  FIG. 1 . 
         [0090]    It proposes two lids  230  and  240 , each with electrical connection disks  231  and  241  with an external diameter that is less than that of the cylinder  211 . 
         [0091]    In this case, the small collars  232  and  242  are placed within the cylinder  211 . 
         [0092]    Each of the annular channels  236  and  246 , formed by the external faces of the small collars  232  and  242  and the internal wall of the cylinder  211 , is then created within the cylinder  211 . 
         [0093]    In this case, each positioning gasket  510  and  520  is respectively fitted tightly on the lids  230  and  240 , and more precisely on the small collars  232  and  242 , within the cylinder  211 , with a smooth external surface to allow the cylinder  211  a slight latitude of movement in relation to each of the lids  230  and  240 . 
         [0094]    In a manner similar to  FIG. 1 , each positioning gasket  510  and  520  is respectively covered by a bonding height  610  and  620  in the annular channels  236  and  246  in order to fix the main body  211  of the envelope  200  to each of the lids  230  and  240 . 
         [0095]    Another embodiment variant of an electrical energy storage system  100  proposes to replace each of the aforementioned positioning gaskets  510  and  520  by a certain thickness of a layer of the elastomer or plastic type on the outer wall of the cylinder  211  or of the small collars  232  and  242  of the lids  230  and  240 . 
         [0096]    Such a layer acting as a positioning gasket, extends along the main body  211  of the envelope  200 , at a height that is suitable for that of the small collars  232  and  242 . 
         [0097]    In the variant of  FIG. 1   a , each lid  230  and  240  has a double small collar  232 ,  233  and  242 ,  243 , which forms a channel  236 ,  246  in which is placed one end of the cylinder  211  with a positioning gasket  510 ,  520  at the bottom of the channel, and a bonding element  600  according to the invention between the joint and the outside of the channel. 
         [0098]    In another variant, illustrated in  FIG. 1   d , it is the cylinder  211  that has an additional small external collar, referenced  213 ,  215 , at each of its ends. Together with the end of the cylinder  211 , the latter forms a channel  236 ,  246  in which is placed the small collar  232 ,  242  of a lid  230 , 20 with, a positioning gasket  510 ,  520  at the bottom of channel and a bonding element  600  according to the invention between the joint and the outside of the channel. 
         [0099]    Several configurations of the lids  230  and  240  capable of closing off the envelope  200  containing the coiled electrical energy storage element will now be described in relation to  FIGS. 3 to 8 . 
         [0100]    In general, each lid  230  or  240  has an electrical connection disk  231  equipped with stiffening strips  290  and welding strips  280 . 
         [0101]    The stiffening strips  290  have a double function, namely a mechanical rigidity role and the role of electrical conductor for the passage of current. The welding strips  280  are used as electrical connection means in order to create the electrical connection between the coiled electrical energy storage element and the lid  230  or  240 . 
         [0102]    In addition, as illustrated in  FIG. 3 , each lid  230 , or even  240 , includes an electrical connection terminal  239  on its opposite outer face  233  within the main body  211  of the envelope  200 . 
         [0103]    The latter is of cylindrical revolution form and placed at the centre of the electrical connection disk  231 . 
         [0104]    Other variants of electrical connection  239  terminals are also possible. They are not limited to the example illustrated in  FIG. 3 . As non-limiting examples, it is possible to mention screwed electrical connections of the male or female type, rings or indeed indented tapered terminals. 
         [0105]    The stiffening strips  290  and the welding strips  280  are distributed angularly in a uniform manner around the electrical connection terminal  239 . 
         [0106]    Furthermore, the thickness of the different welding strips  280  is calibrated for laser welding by transparency as will be described particularly in relation to  FIG. 4 . This is of the order of 0.4 to 1 mm and, preferably, of 0.7 to 0.8 mm. 
         [0107]    In a variant, creation of the electrical link between the lids  230 ,  240  and the coiled element is effected by diffusion brazing, in particular by cold diffusion brazing with the addition of gallium. In the case of such a connection by brazing or diffusion brazing, the thickness of the welded zones will preferably be between 0.4 mm and 3 mm. 
         [0108]    In an alternative to laser welding by transparency, it will also be possible to create the connection by welding using any other appropriate conventional technique. 
         [0109]    Moreover, as illustrated in  FIGS. 5   b ,  6   b  and  7   b , the small collar  232  (or  242  of the lid  230  (or  240 ) can be extended at each welding strip  280  so that it opens onto the outer face  233  of the disk  231  and forms a lip  238  that allows the creation of a well, such as a well to accommodate an adhesive or any other resin. The connection strips are thus rendered sealed to fluids after their connection, by the addition of a layer of adhesive or of resin over all of their surface. 
         [0110]    According to the first embodiment variant illustrated  FIG. 3 , the lid  230  has an electrical connection disk  231  that is initially flat, and partially stamped according to at least one profile that corresponds generally with a radius created from axis X-X to form at least one radial rib constituting a welding strip  280  in the form of at least one convex boss  281  inside the main body  211  of the envelope  200 . According to  FIG. 3 , four such bosses  281  are this distributed around axis X-X. In this case the stiffening strips  290  are formed by a circular sector contour between two welding strips  280 . 
         [0111]    As can be seen by studying  FIG. 4 , on the inner face  234  of the electrical connection disk  231 , the profile of each boss  281  acts as a bearing surface for the coiled electrical energy storage element. 
         [0112]    More precisely, the current collecting part of the coiled electrical energy storage element, which is concave toward the inside of the element, engaged in a complementary manner with the different bosses  281  of the lid  230  to which it is then connected electrically by welding along the profiles of the latter. 
         [0113]    As illustrated in  FIG. 5   a , the bosses  281 , of parabolic or trapezoidal cross section, are preferably distributed angularly in a uniform manner around axis X-X of the electrical connection terminal  239 . 
         [0114]    They extend, lengthways, radially in relation to axis X-X and open onto the outside of the disk  231 . 
         [0115]    Other embodiment variants of the lids  230  and  240  illustrated in  FIGS. 6 and 7 , specify a lid that includes an electrical connection disk  231  with a flat inner face  234  and an outer face  233  with stiffening strips  290  and welding strips  280 . 
         [0116]      FIG. 6  illustrates a variant in which stiffening strips  290  take the form of radial ribs  292  in relation to axis X-X and opening onto the outside of the disk  231 . 
         [0117]    In a non-limiting example of the invention, these form a four-branched cross on the outer face  233  of the disk. 
         [0118]    The stiffening strips  290  alternates with welding strips  280  in a circular sector shape, of low thickness, which extend in width over a minimum distance of 1 to 3 mm. 
         [0119]      FIG. 7  illustrates another variant in which welding strips  280  take the form of radial recesses  283  in relation to axis X-X (four recesses  283  distributed evenly around axis X-X, as in  FIG. 7 , but this example is not limiting in any way) while the remainder of the disk  231 , with its main thickness, takes the form of a series of stiffening strips  293  each with the geometry of one sector of a cylinder. 
         [0120]    These recesses  283 , of substantially rectangular straight section, distributed uniformly over the disk  231  extend radially and open onto the outside of the disk  231 . 
         [0121]    The embodiment variants of lid  230  or  240  with one disk  231  having a flat inner face  234  can be accompanied by one or more connection straps  295 , illustrated in  FIG. 9 , in order to create the electrical link between the lid  230  or  240 , within the main body  211  of the envelope  200 , and the current collecting part of the coiled electrical energy storage element. 
         [0122]    This electrical connection strap  295  comes for example in the form of a rectangular part with a flat outer face  296  and an inner face  297  with a boss  298  extending over its length. 
         [0123]    The boss  298 , of parabolic or trapezoidal section for example, will engage on the convex side with the element of the coiled electrical energy storage element that is embossed in a complementary manner, and will be attached to it by a welding process. 
         [0124]    In a variant, the electrical connection strap  295  comes in the form of a star that groups together several parts with bosses  298  that are organised radially around the centre of the star. 
         [0125]    However, in the case in which the lid  230  or  240  with the flat inner face  234  is used without the small connecting strap  295 , the coiled electrical energy storage element should preferably have flattened current collecting elements at its two ends that are parallel to the inner face  234  of the electrical connection disk  231  in order to create a large continuous bearing surface during the electrical connection between the lid  230  or  240  and the coiled element. 
         [0126]    According to another embodiment variant of the lids  230  and  240  illustrated in  FIG. 8 , in order to weld all the turns of the coiled electrical energy storage element, even though these turns are not all on a given radius, provision is made for several series of bosses  284  of substantially rectangular straight section, distributed angularly in a uniform manner on the lid  230 , and covering variable radial extensions on the surface of the lid  230 . 
         [0127]    More precisely, according to  FIG. 8 , the bosses  284  are divided into two series  285  and  286 . More precisely still, according to  FIG. 8 , provision is thus made for a first series of radially internal bosses  285  (four bosses  285 , for example) distributed angularly in a uniform manner around axis X-X, and a second series of radially external bosses  286  (also four bosses  286 , for example) that alternate with bosses  285 , and are also distributed in an angular fashion. 
         [0128]    These bosses  284  are preferably as described in relation to  FIGS. 3 to 5 . 
         [0129]    In an embodiment variant not illustrated in the figures, but which can be understood from the description alone, it is possible to insert, between the current-collecting elements and the inner part of the lid, at least one thin layer of conducting metal sheeting that covers at least the surface lid to collecting element connection strips. This thin sheet is added in order to compensate for any lack of connection material during the welding of the lid onto the current-collecting elements. 
         [0130]    In another variant of the same type, the thin metal sheet can be created in the form of a star whose branches cover the surface of the lid-current-collecting element connection strips. 
         [0131]    Finally, if experience shows that it is desirable, it will be possible to add several layers of thin metal sheeting capable of supplying a large quantity of connection material without the need to provide a large amount of energy for the weld. 
         [0132]    Another method, forming an integral part of the invention, of supplying connection material could be to effect material spraying onto the current-collecting elements of the coiled energy storage element in order to improve contact between the said elements and the lid or the intermediate connection part. 
         [0133]    In all of the cases described above, the connection strips of the current-collecting elements can be effected by radial layering of the current-collecting elements from the centre to the outside of the coiled energy storage element, in order to increase the contact area between the said elements and the lid or the intermediate connection part. 
         [0134]    In addition, as illustrated in  FIGS. 10   a  and  10   b , according to an embodiment variant of a system  100  according to the invention, the main body  211  of the envelope  200  is equipped with at least one anti-opening bellows  225 , with a view to preventing a rise of internal pressure during the ageing of the electrical energy storage system  100  and, particularly the generation of gas. 
         [0135]    Each bellows  225  is formed, for example, of an annular rib  226  covering the whole circumference of the cylinder  211 . 
         [0136]    The bellows  225  is calibrated, in form and dimensions, to allow the cylinder  211  to extend, by expansion, under the effect of the rise of internal pressure, while still maintaining its seal. 
         [0137]    The extension of the cylinder  211 , as illustrated  FIG. 10   b , causes electrical disconnection between the coiled electrical energy storage element and the associated lid  230  due to the fact that the coiled electrical energy storage element itself cannot extend. 
         [0138]    The rupture of the electrical link brings to a stop the ageing phenomenon that is at the origin of the pressure rise. 
         [0139]    The electrical energy storage system  100  is thus mad secure by being switched to an open circuit. 
         [0140]    In a variant, such an anti-opening safety bellows  225 , acting in the event of high internal pressure, can be placed on a lid  230  or  240  between the bonding zone of the lid and the interior of the latter. 
         [0141]    Finally, as shown in  FIG. 16 , an enhancement to the invention enables the addition of a central tubular canal  150  placed within the spool of the coiled energy storage element, the said canal  150  opening out right through at least one of the lids  230 ,  240 , to allow the circulation of a heat-bearing fluid for use in thermal regulation of the system. 
         [0142]    This central canal  150  can take the form of hollow aluminium tube  152 , attached to one of the two lids  230  or  240 , and affixed to the other lid, by bonding to a small central collar  151  belonging to the said other lid. In a variant, the tube  152  can be independent of each lid but affixed to a small collar fitted to each lid. 
         [0143]    A method for the embodiment of a system for the storage of energy electrical  100  according to the invention is now described in relation to  FIG. 12 . 
         [0144]    In a first step  810 , the current collecting elements of the coiled electrical energy storage element are prepared so as to create the electrical link between the element and the type of lid  230  and  240  chosen to close off the main body  211  of the envelope  200 . 
         [0145]    More precisely, if the lids  230  and  240  include an electrical connection disk  231  with bosses  281  as described in relation to  FIGS. 3 to 5 , then the current collecting elements of the element are embossed in a complementary manner to these bosses  281 , while if the lids  230  and  240  have an electrical connection disk  231  with a flat inner face  234 , then the current collecting elements are flattened parallel to this inner face  234 . 
         [0146]    Furthermore, if connection straps  295  are used, these are welded to the embossed current collecting elements of the coiled electrical energy storage element during step  820 , with the current-collecting elements being folded back, or not, by radial layering from the centre to the outside of the coiled element. 
         [0147]    Next, at step  830 , the coiled electrical energy storage element is inserted into the cylinder  211 , which has been pre-fitted with the positioning gaskets  510  and  520  at its two opposite ends  212  and  213 . 
         [0148]    It is then centre and blocked within the cylinder  211  by a central shrinkage operation on the latter (step  840 ). 
         [0149]    The two lids  230  and  240  are then placed respectively at the two opposite ends  212  and  213  of the cylinder  211  at step  850 . 
         [0150]    In step  860 , the electrical link is then created between the lids  230  and  240  and the coiled electrical energy storage element by transparency laser welding of the current collectors of the element onto the welding strips  280  of each lid  230  and  240  with which they are held contact by pressure. 
         [0151]    At step  870 , a bonding height  600  is deposited one or other of the annular channels  236  and  246  and surmounts the corresponding positioning gasket  510  or  520 . 
         [0152]    The system  100  is then raised to a certain temperature in order to cure the adhesive  600 , using techniques that in themselves are familiar. It is possible to mention, as non-limiting examples, a curing process either at to ambient temperature or at high temperature, in a general manner by the use of an oven or, in a local manner by means of a ring heated by induction or infra rouge, or by UV, or any other equivalent means. 
         [0153]    Step  870  is repeated for the second lid  230  or  240  in a similar manner. 
         [0154]    We thus obtain a system for the storage of energy  100  according to the invention. 
         [0155]    In an embodiment variant of this method, a pre-bonding process is effected at step  825 , on one of lids  230  or  240  at one end  212  or  213  of the main body  211  of the envelope  200 , pre-fitted with the positioning gaskets  510  and  520  before insertion of the coiled energy storage element into the cylinder  211  at step  830 . 
         [0156]    The following steps remain identical to those described previously, except that the final bonding step  870  now concerns only the bonding of the second lid  230  or  240  to the cylinder  211 . 
         [0157]    In a third embodiment variant of this method, the step  870  for affixing the different lids  230  and  240  to the cylinder  211  is effected before the step  860  for welding of the lids  230  and  240  to the coiled electrical energy storage element. 
         [0158]    In this case, the bonding, at one and then the other end of the main body  211  of the envelope  200 , is accomplished by holding the two lids  230  and  240  under pressure onto the current collecting elements of the coiled electrical energy storage element, with a view to maintaining optimal contact before welding the element to each of the lids  230  and  240 . 
         [0159]    In addition, an embodiment variant of an electrical energy storage system  100  according to the invention provides for the use of a cylinder  211  that is equipped with a solid bottom in the form of a lid. 
         [0160]    In this case, step  840  for central shrinkage of the main body of the envelope is deleted. The coiled electrical energy storage element connected mechanically to the cylinder  211  then remains floating before the welding step  860 . 
         [0161]    Furthermore, an operation for affixing a lid is deleted at step  870 . 
         [0162]    In a fourth embodiment variant of the method, laser welding by transparency allowing creation of the electrical link between the coiled energy storage element and the lids  230  and  240  is replaced by a brazing/diffusion method, such as Gallium brazing/diffusion. 
         [0163]    In this method, a deposit of gallium is placed on the inner face of each lid  230  and  240  and brought into contact with the current collecting elements of the element. The whole is then brazed in order to effect the electrical connection of the different elements. 
         [0164]    It should be noted that the embodiment of this method requires the use of positioning gaskets  510  and  520  that are resistant to the brazing/diffusion temperatures. 
         [0165]    This method for the assembly of an energy storage element can be adapted to be used for the creation of an electrical energy storage module  110  such as that which will now be described in relation to  FIGS. 13 to 15 . 
         [0166]      FIG. 13  illustrates the association of two electrical energy storage systems  100  forming an electrical energy storage module  110 . 
         [0167]    Each of the electrical energy storage systems  100  is as described previously in relation to  FIGS. 1 and 2 . 
         [0168]    However, at a given end of each of their respective cylinders  211   a  and  211   b , the two systems  100  enclose their coiled electrical energy storage element  700  by virtue of an electrical common connecting part  900  with two conducting lids  230   a  and  230   b , each intended to be attached to one of the electrical energy storage systems  100 . 
         [0169]    This part  900  is thus used in order to create the electrical link between the two juxtaposed electrical energy storage systems  100 . 
         [0170]    As illustrated in  FIG. 14 , the part  900  is in the form of a plate  910  that includes, respectively at each of its ends  911  and  912 , an electrical connection disk  231   a  and  231   b  equipped on its circumference with a small collar  232   a  and  232   b , and central strap  920  that connects the two disks  231   a  and  231   b.    
         [0171]    Returning to  FIG. 13 , the outer face  914  of the plate  910  is flat, while the inner face  915  of the plate  910 , which engages with a main body  211  of each envelope  200   a  and  200   b  has the two small collars  232   a  and  232   b.    
         [0172]    The main body  211  of the envelope  200  of each of the two electrical energy storage systems  100  of such a module is attached to this part  900  and, more precisely, each to one of the lids  230   a  and  230   b  of the plate  910  by a positioning gasket  500 /bonding element  600  assembly. 
         [0173]    In a embodiment example in which an electrical energy storage module  110  with two systems  100  is intended to be functional alone, the two lids  240   a  and  240   b , which are independent of each other and opposite to the twin-lidded plate  910 , connected by electric welding, within each of the main envelope bodies  200 , to the two spooled electrical energy storage elements, each having an electrical connection terminal  239  on its outer face. 
         [0174]    In order to form a module  110  with more than two spooled electrical energy storage elements, as illustrated in  FIGS. 15   a  and  15   b , the electrical chaining of the systems  100  is effected by means of the plates  910 . 
         [0175]    According to  FIG. 15   b , these plates  910  are placed alternately as the upper twin lid and then the lower twin lid of the main envelope body  200 ,  211  of pairs of juxtaposed electrical energy storage systems  100 . 
         [0176]    Thus, in order to create a module of n spooled electrical energy storage elements associated in series, where n is equal to or greater than 3, the systems  100  will be connected together in pairs by means of n−1 twin lids  900 . The twin lids  900  are provided successively at opposite ends of the energy storage systems  100 , where the systems placed at the ends of the series chain constituting the module are connected to the external application by means of individual lids  230 ,  240 . 
         [0177]    Conversely, if it is desired to create a module  110  of n electrical energy storage systems  100  in a parallel association, with n being equal to or greater than 2, then all the isopotential ends of the systems will be connected together at a given end by a single lid with as many connection means (small collar  232 ,  242 , positioning gasket  510 ,  520 , or adhesive  610 ,  620 ), as there are systems to be connected in parallel. 
         [0178]    Finally, if it is desired to create a module  110  with at least one combination of series connected or of parallel connected systems  100  or a group of systems  100 , then those skilled in the art will be able to adapt in the required number of single lids  230 ,  240  and of twin lids  900 , combined together so as to allow the said series or parallel connection of the said systems  100  or groups of systems  100 . 
         [0179]    A system  100  provided at one end of the module  110  has a main body  211  that is closed at one end  213  by a lid  240  equipped with an electrical connection terminal  239 , with this terminal being used as either of the output connections of the electrical energy storage module  110 . 
         [0180]    At the opposite end  212 , the same main body  211  is closed off by either of the lids  230  of a plate  910 , with the other lid  230  of the same plate  910  closing off the main body  211  of the envelope  200 , at the same end  212  of a juxtaposed system  100 . 
         [0181]    This system  100  is itself connected to another juxtaposed system  100  by another twin-lidded plate  910  placed at the opposite end of the first plate  910  and so on. 
         [0182]    On the last electrical energy storage system  100  of the module  110 , the second electrical connection terminal  239  used as the second of the two output terminals of the module  110 , is placed on a lid  240 . 
         [0183]    The advantage arising from this module configuration  110  is removal of the connecting parts between the different electrical energy storage systems  100 . 
         [0184]    Furthermore, the welding steps are reduces, since there remains only that of the twin-lidded plates  910  onto the spooled electrical energy storage elements. 
         [0185]    Those skilled in the art will appreciate a system  100  for the storage of electrical energy that offers simple and reliable configuration, created by bonding, while still proposing a precise and effective electrical connection. 
         [0186]    Furthermore, in relation to the known devices of the prior art, this system has a sealing system that is resistant to very high internal pressures and whose adjustable seal attains values below 10 −9  mbar.l.s −1 . 
         [0187]    In addition, this system  100  for the storage of electrical energy offers the advantage of achieving savings in terms of cost, time, and space. 
         [0188]    Finally, the present invention is not limited to supercapacitors, and can be implemented for any assembly for the large-scale storage electrical energy. One might mention generators, batteries or capacitors, as non-limiting examples. 
         [0189]    The present invention is naturally not limited to the particular embodiments that have just been described, but extends to any variant that complies with its spirit. In particular, the present invention is not limited to the appended drawings. The specific references illustrated in the preceding paragraphs are non-limiting examples of the invention.

Technology Category: 4