Abstract:
An electric power storage cell including several electrochemical elements connected in series and/or in parallel, arranged inside a sealed casing. The casing electrically connects the electrochemical elements to a power connecting device outside the casing. The electrical connection is configured so that the casing can be traversed without affecting adversely the tightness thereof and without transmitting stresses to the casing. The storage cell has applications in the field of lithium polymer technologies with high power storage assemblies.

Description:
The present patent application is a non-provisional application claiming the benefit of International Application No. PCT/EP2006/064223, filed Jul. 13, 2006. 
     FIELD OF THE INVENTION 
     The invention concerns electrical energy storage assemblies. It applies, in particular, but non-limitatively, to batteries of the lithium polymer type. More precisely, this present invention concerns the sealing and the electrical connection of electrical energy storage cells forming an electrical energy storage assembly. 
     PRESENTATION OF THE PRIOR ART 
     A large number of energy storage assemblies, called high energy storage assemblies, have been proposed in recent times, such as lithium polymer assemblies for example. 
     However the known devices have not been totally satisfactory in respect of the sealing of the power connections to their electrical energy storage cells. 
     This is an objective that people have already sought to attain in many implementations, though never producing results that are fully satisfactory. 
     Conventionally, an electrical energy storage cell includes a sealed casing in which are placed different electrochemical elements which are connected by electrical link means and at least one electrical connection that has electrical link terminals of opposite polarity projecting outside of the casing. 
     During the assembly of an electric energy storage cell, the terminals are fixed to the casing, inside the cell, by bolted means, screwed means or by cold working of the metal of their component elements. 
     Mention will also be made of the use of sealing washers or indeed of o-rings to reinforce the sealing of the electrical link terminals, and as a consequence of the electrical connection. 
     However up to the present time, these creations have had as their common feature the at least partial penetration of the electrical connecting terminals into the inside of the casing of the electric energy storage cell in order to be attached there. 
     This attachment is a complex process, and the presence of the terminals inside the cell favours their exposure to the electrolyte environment of the electrochemical elements, thus giving rise to sealing problems. 
     The invention in particular aims overcome the drawbacks of the prior art. 
     One objective of the present invention is to propose an electric energy storage cell that offers a sealed electrical connection system while still presenting a precise, simple, secure and reliable electrical connection. Another objective of the present invention is to propose an electric energy storage cell that offers a sealing system that has a simple and effective configuration. 
     It is also desirable to propose electrical link terminals that offer a saving in terms of costs, weight, and space in the creation of an electric energy storage cell. 
     SUMMARY OF THE INVENTION 
     According to the invention, these aims are achieved, by means of an electric energy storage cell that includes several electrochemical elements connected in series and/or in parallel, placed inside a sealed envelope, where said envelope includes means for electrical connection of the electrochemical elements to a power connecting device outside of the envelope, characterised in that the electrical connecting means include means that are suitable to allow passage through the said envelope without affecting the sealing there of, and without the transmission there to of support stresses. 
     More precisely, the invention proposes an electric power storage cell that includes electrical connecting means for the said electrochemical elements on the inside of the envelope, and in which the electrical connecting means include electrical connecting terminals placed in two passages that pass through the envelope, where the electrical connecting means include two connecting plates respectively associated with the electrical connecting terminals, said terminals each including an electrical stud and a pin, where the two pins, together with the means to prevent pin rotation, are used to secure the two connecting plates respectively to the two electrical connecting studs by means of clamping means, where said clamping means also effects the rings by the clamping of two sealing rings, each inserted between a shoulder on a stud and the sealing envelope. 
     According to an advantageous characteristic of the invention, the connecting plates are inserted between the electrical connecting studs and the pins. 
     According to another advantageous characteristic of the invention, a connecting assembly that includes an electrical connecting terminal which includes an electrical stud and a pin, a sealing envelope and a connecting plate, includes an electrically-conducting connecting part and spring elements, with the said spring elements holding the connecting part in close contact on two terminals of two adjacent cells, with an intermediate contact part being interposed between the connecting part and each of the terminals in order to favour the electrical contact between the said parts. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
       The invention will be more clearly understood, and other advantages and characteristics will emerge more clearly on reading the description that follows and which is provided by way of a non-limiting example and with reference to the appended drawings. 
         FIG. 1  illustrates a view in perspective of the assembly of an electric energy storage cell according to the invention; 
         FIG. 2  illustrates a side view of an electrical stud of an electric energy storage cell according to the invention; 
         FIG. 3  illustrates a view in perspective of the underside of an electrical stud of an electric energy storage cell according to the invention; 
         FIG. 4  illustrates a view in partial section at the level of an electrical stud of an electric energy storage cell according to the invention; 
         FIG. 5  illustrates a view from above of the assembly of a pin on a plate of an electric energy storage cell; 
         FIG. 6  illustrates a partial view in perspective of the electrical assembly, in series, of electrical connecting studs of electrical energy storage cells via a power connecting device; 
         FIG. 7  illustrates a view in perspective of an electrical stud of an electric energy storage cell assembled electrically to the power connecting device; 
         FIG. 8  illustrates a system for the interconnection of a set of electrical energy storage cells with a means for controlling its healts status; 
         FIG. 9  illustrates the assembly of an electrical stud of an electric energy storage cell with the interconnection system of  FIG. 8 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  illustrates the different elements forming an electrical energy storage cell  100  according to the invention. 
     An electrical energy storage cell  100  includes a sealed envelope  400 , including two traversing passages  410 , several electrochemical elements  110  placed inside the envelope  400 , electrical link means  600  for said electrochemical elements  110 , inside the envelope  400 , and means for electrical connection of the electrochemical elements  110  to a power connecting device outside of the envelope  400 , with this device being illustrated in  FIGS. 6 and 7 . 
     These electrical connecting means include electrical connecting terminals  901 ,  902  placed in the passages of the envelope  400  and, also, a set of two plates of rectangular shape, a bottom plate  200  and a top plate  300 , placed inside the envelope  400 . 
     These means will allow one to pass through the envelope without affecting the sealing there of and without the transmission of support stresses thereto on the part of the electrical connecting terminals  901 ,  902 . 
     The sealing envelope  400  takes the form of a rectangular casing shown in the figure with its length on the X axis and its width on the Y axis. 
     The two traversing passages  410  are circular and respectively present, on the two opposite ends  402 ,  403  of the top face  401  of the envelope  400 , the face perpendicular to the X axis. 
     The sealing envelope  400  is preferably flexible and includes a metal layer forming a waterproof barrier. 
     It houses an arrangement of parallel electrochemical elements  110 , of substantially rectangular shape, lying longitudinally along the X axis. 
     The two rectangular-shaped plates  200 ,  300 , have a length and a width designed to cover the top section of the arrangement of electrochemical elements  110 , perpendicular to the X axis. 
     Each of these is preferably semi-rigid and made of plastic. 
     Inside the envelope  400 , the bottom plate  200  is placed in contact with the section of electrochemical elements  110 , while the top plate  300  is in contact with the sealing envelope  400 . 
     In addition, the bottom plate  200  includes a network of ribs  210  each designed to accommodate one electrode of the electrode pair  115  of an electrochemical element  110 . 
     This network  210  lies along the longitudinal ends  203 ,  204  of the bottom plate  200 . 
     The electrodes  115  are thus placed in a plane that is perpendicular to the X axis, in contact with the bottom plate  200 . 
     These electrodes  115  are connected to the electrical link means  600  and, more precisely, to two connecting plates  600  surmounting the bottom plate  200 . 
     A connecting plate  600  is composed of a concentrator  600  of electrical energy. 
     A single concentrator  600  is illustrated in  FIG. 1 . It is of more-or-less triangular shape, and lies, in terms of its length, perpendicularly to the X and Y axes. 
     It includes a series of juxtaposed individual connection means  610 , each designed to connect with one electrode  115  of the same polarity of an electrode pair  115 . 
     These means  610  are placed along the longitudinal end  601  of the concentrator  600 , the end parallel to the longitudinal end  203  of the bottom plate  200 . 
     In addition, close to its ends  301 ,  302  the top plate  300  has two circular holes  311 ,  312 . 
     These holes  311 ,  321  are extended, on the top face of the top plate  300  parallel to the X axis, respectively by two circular collars  310 ,  320 . 
     Their position will coincide with those of the two traversing passages  410  of the sealing envelope  400 . 
     In addition, the external diameter of the passages  410  is substantially identical to the internal diameter of the two collars  310 ,  320 . 
     The traversing passages  410  and the holes  311 ,  321  provide a crossing in the envelope  400  and in the top plate  300  to two electrical link terminals  901 ,  902 , of negative and positive polarity respectively. 
     These two terminals  901 ,  902  each respectively includes a pin  801 ,  802  and an electrical connection stud  501 ,  502 . The electrical connection studs  501 ,  502  will be described later with reference to  FIGS. 2 and 3 . 
     With the two circular holes  311 ,  312  of the top plate  300  providing a passage through the plate  300 , the studs  501 ,  502  are attached, inside the cell  100 , to the two concentrators  600 , by means of a screw thread on the pins  801 ,  802 . 
     Each pin  801 ,  802  includes a threaded extended body  810  parallel to the X axis, and an annular shoulder  820  centred on the body  810 . 
     Each of these pins  801 ,  802  is mounted in a housing provided for this purpose on the bottom plate  200  as described with reference to  FIG. 5  for pin  802 . In this figure, it can be seen that the latter is associated with means to prevent rotation. 
     In fact it is housed in a complementary shape  270  that has a flat spot  275  created in the bottom plate  200 , by the bottom face  821  of its shoulder  820  having an identical flat spot  825  on its circular profile. 
     Returning to  FIG. 1 , two casings  260 ,  270  for the pins  801 ,  802  are placed respectively at each of the ends  201 ,  202  of the bottom plate  200  so as to coincide with the circular holes  311 ,  321  in the top plate  300 . In addition, each pin  801 ,  802  is mounted to float in its casing  260 ,  270  and in a hole  620  in the connecting plate  600  in order to allow self-centring of the pin in relation to the terminal. 
     Each of the concentrators  600  is screwed onto one of the pins  801 ,  802  through a circular hole  620 , whose internal diameter is matched to that of the extended body  810  of the pins  801 ,  802  and it is then click-fitted to the bottom plate  200 . 
     In addition, on these two widths  201 ,  202 , the latter includes a series of click-on fittings  250  that are designed to mate with reception elements  350  respectively present on the widths  301 ,  302  of the top plate  300 , in order to click-fit the top plate  300  onto the bottom plate  200 , thus enclosing the concentrators  600  and the annular shoulders  820  of the aforementioned pins  801 ,  802 . 
     Another embodiment could include the presence of the click-on fittings  250  on the top plate  300  and the reception fittings  250  on the bottom plate  200 . 
     The extended bodies  610  of the pins  801 ,  802  project outwards from the top plate  300  via the two holes  311 ,  321 . 
     In addition, the pins  801 ,  802  mate in a complementary manner with the two electrical connection studs  501 ,  502  which will now be described with reference to  FIGS. 2 and 3 . 
       FIG. 2  shows the electrical connection stud  502  configured to be fixed onto the electrical energy storage cell  100 , essentially on the outside of the sealing envelope  400 . 
     This stud  502  whose role is to provide electrical conduction from the interior of a cell  100 , which contains all of the electrochemical elements  110 , to the exterior, includes a cylindrical main shaft  510  lying parallel to the X axis. 
     This cylinder  510  is extended by two coaxial annular shoulders  520 ,  530 , of larger diameter, namely a primary shoulder  530  present at the proximal end of the cylinder  510 , close to the plate  200 , and a secondary shoulder  520  present at the distal end of the cylinder  510 , away from the plate  200 . 
     By means of their inner faces  522 ,  531 , these form the branches of an annular channel  570 . 
     In addition, at the proximal end of the cylinder  510 , the primary shoulder  530  is surmounted on its inner face  531  by a coaxial stamping  550 , which will be used for securing the electrical connection stud  502  onto the electrical energy storage cell  100 . 
     This stamping  550  includes at least one flat spot, and its edges have a fillet  555  formed by a surface that converges toward the primary shoulder  530  as one moves radially toward the exterior. 
     This fillet  555  will be used to facilitate the attachment of clamping device against the electrical stud  500 . 
     The primary shoulder  530  is also extended, on its outer face  532  by a second coaxial cylinder  540 , of smaller diameter, which in part provides the electrical connection to one of the connecting plates  600 . 
     As illustrated in  FIG. 3 , this second cylinder  540  presents, on its outer face  542 , opposite to the outer face  532  of the primary shoulder  530 , concentric splines  545 , centred on the main shaft  510  playing the role of conducting electrical connectors. 
     In addition, the electrical link stud  502  is equipped with an internal threaded passage  560  of cylindrical shape. It is coaxial with the main shaft  510  and opens to the exterior at the outer face  542  of the cylinder  540 . 
     This passage  560  is designed to receive and to engage with pin  802  so as to secure the electrical connection terminal  902  to all of the plates  200 ,  300 . 
     In addition, the primary shoulder  530  of the stud  502  includes, on its outer face  532 , an annular channel  535  running around all of its circumference, whose walls are formed by the cylinder  540  and by the outer wall  534  of the primary shoulder  530 . 
     This channel  535  is configured, in both size and shape, to receive a sealing element  700 . 
     This element  700  is preferably a sealing o-ring of circular section. 
     The top plate  300  includes at least one collar  310 ,  320  forming, together with the channel  535 , a casing of such a nature as to compress the sealing o-ring  700  between each of the studs  501 ,  502  and the flexible envelope  400  flattened against the top surface of the top plate  300 . 
     Advantageously, each collar  310 ,  320  of the top plate  300  also constitutes an electrical separator between the edge of the envelope  400  and the cylinder  540  of the studs  501 ,  502 , thus providing the electrical between the envelope  400  and the latter. 
     Returning to  FIG. 1 , it can be seen that the two studs  501 ,  502  as described above with reference to  FIGS. 2 and 3 , are intended to be placed on the top face  401  of the sealing envelope  400 , with their main shaft  510  lying parallel to the X axis. They will allow the electrical link terminals  901 ,  902  to provide sealed electrical connections through the sealing envelope  400 , as illustrated in  FIG. 4 , by the stud  502 . 
     As illustrated in the figure, the cylinder  540  of the electrical stud  502  is inserted into the hole  321  in the top plate  300  until the concentric splines  545  come up against the concentrator  600 . 
     The cylinder  540  of the stud  502  is centred on the threaded extended body  810  to pin  802 , with this pin  802  projecting outside of the envelope  400  via a through passage  410  centred around the collar  320  of the top plate  300 . 
     The installation of the concentrator  600  around the extended body  810  of the pin  802  is preferably facilitated by the presence of a chamfer  815  on the end of the body  810  of the pin  802  opposite to the annular shoulder  820 . 
     This chamfer  815  is determined by a surface that converges toward the shoulder  820  as one moves radially toward the exterior. 
     With the pin  802  being engaged on the cylinder  540  of the stud  502 , the splines  545  present on the inner surface  542  of the cylinder  540  enter into contact with the concentrator  600  and create large compression zones during the attachment of the terminal, thus favouring the quality of the electrical contact. 
     Advantageously, each electrical terminal  901 ,  902  creates a direct electrical connection with a concentrator  600  through a passage  410  in the sealing envelope  400  of the energy storage cell  100 . 
     In addition, two elastomer sealing elements  700  are placed on the envelope  400 , each around a collar  310 ,  320  on the top plate  300  projecting outside of the sealing envelope  400 . 
     By engaging the electrical connection stud  502  with the pin  802  via its threaded passage  565 , each of the sealing elements  700  is trapped in a closed channel whose branches are formed firstly by the annular channel  535  of the bottom shoulder  530  of the stud  502  and secondly by the collar  320  on the top plate  300 . 
     Advantageously, the studs  501 ,  502  thus perform the role of sealing elements above the passages  410  passing through the sealing envelope  400 . 
     According to the invention, by securing the stud  502  via the retention stamping  550  allowing the use of an open-ended torque wrench, it is possible not only to effect the electrical contact of the stud  502  onto the concentrator  600  but also clamping of the sealing element  700  onto the envelope  400  in the closed channel. 
     Advantageously, in a single clamping operation, a suitable clamping pressure can guarantee the electrical concentrator  600 /stud  502  contact and the correct clamping pressure on the ring  700  in the channel  535  in order to guarantee the sealing of the stud  502 /envelope  400  junction. 
     This construction enables to avoid direct electrical contact between the two studs  501 ,  502  in a cell  100  by means of the section of the flexible conducting envelope  400 . 
     Indeed, the collars  310 ,  320  allowing the electrical separation of each stud  501 ,  502  in the cell  100  and the section of the envelope  400  prevent short circuits occurring in the cell  100 . 
     Advantageously, the electrical link terminals  901 ,  902  do not open into the cell  100 . They provide a sealed electrical through connection at the level of the traversing passages  410  of the sealed electrical through connection at the level of the traversing passages  410  of the sealing envelope  400 . 
     In  FIG. 4 , we also see an example of a power connecting device used to electrically connect several electrical energy storage cells  100 . 
     This system will now be described with reference to  FIGS. 6 and 7 . 
     This system includes an electrically-conducting part  54  as well as two spring elements  70  for the connection in series of two electrical link studs  500 ,  502  of a pair of electrical energy storage cells  100 . 
     As illustrated in  FIG. 6 , the electrical link stud  502  of the cell  100  is linked to an electrical link stud  500  of the neighbouring cell (not illustrated) by means of a busbar  54  of substantially rectangular shape. 
     One end  53  of the busbar  54  is positioned perpendicularly to the shaft  510  of the electrical link stud  502 , on the outer face  521  of the primary shoulder  520 . 
     At this end  53 , the busbar  54  has a square cut-out  51 , centred on the shaft  510  of the electrical connection stud  502 , which will act as a locating point for the installation of a spring element  70  that firstly provides the grip for the electrical connection stud  502 /busbar  54  contact, and also the grip for the electrical connection stud  502 /interconnection system contact  10 , as will be described with reference to  FIG. 8 . This busbar  54  also has, at this end  53 , on either side of the square cut-outs  51 , two cut-back recesses  52 ,  56  lying on each longitudinal side of the busbar  54 . 
     The length of the opposing recesses  52 ,  56  is identical, and corresponds substantially to the external diameter of the electrical connection stud  502 . 
     These recesses  52 ,  56  will allow a contact part  60 , playing the role of contact between the electrical link stud  502  and the busbar  54 , to lock onto the latter. 
     It takes the form of a rectangular plate  61  of U-shaped cross-section, positioned parallel to the shaft  510 . 
     The length of the plate  61  is designed so that it makes contact, respectively, with the recesses  52 ,  56  of the busbar  54  and clicks onto the busbar  54 . 
     The click fitting is achieved by bending backwards of the ends  64 ,  65  of the plate  61  on the top face of the busbar  54 . 
     On the top face  67  that will come into contact with the bottom face of the busbar  54 , the plate  61  has a series of adjacent metal leaves  68  forming rectilinear splines. 
     The busbar  54  is preferably made of tinned copper, and the contact part  60  of beryllium copper. 
     In addition, the spring element  70  is composed of a clamp  70 . This clamp  70  performs the bringing into contact of the primary shoulder  520  of the electrical connection stud  502 /contact part  60 /busbar  54  stack, locking onto this assembly by sliding sideways perpendicularly to the shaft  510  of the stud  502 . It takes the form of a part of U-shaped cross-section that includes a plate  71  and a back-plate  72  which are connected by a linking element  73  and assembled, respectively, with the top face of the busbar  54  and the inner face  522  of the primary shoulder  520  of the stud  502 . 
     The backplate  72  of the clamp  70  is divided, along its length, into two identical brackets  73 ,  74  placed around the shaft  510  of the stud  502 . 
     In addition, the spring element  70  includes, on its plate  71 , a square locking stud which is used to lock the clamp  70  onto the assembly. This stud  75  is located during the sliding action in the square cut-pout  51  of the busbar  54  and is used to prevent the clamp  70  from being dislodged from the electrical connection stud  500  under the mechanical stresses to which the electrical energy storage cell  100  may be subjected. 
     The use of the clamp  70  allows the application of continuous compression forces to the electrical energy storage cells  100 . 
     The power connection system between several electrical energy storage cells  100  can be the subject of many embodiments. It must not be limited to the illustration provided in the aforementioned  FIGS. 6 and 7 . 
     In addition, each electrical connection stud  501 ,  502  of an electrical energy storage cell  100  according to the invention is also designed so as to allow connection of the cell  100  to a monitoring/control device  30 , by means of an interconnection system  10  as illustrated in  FIG. 8 . 
       FIG. 8  illustrates an electrical energy storage assembly  20  formed by an arrangement of several individual electrical energy storage cells  100  placed within a rectangular case forming a hermetic enclosure  21 . 
     The interconnection system  10  is placed flat onto the top face of the casing  21  so as to cover the tops of the electrical energy storage cells  100 , each with two electrical connection studs  500  of different polarity. 
     This flexible system  10  advantageously includes a bypass circuit that includes power dissipation resistances as well as a voltage measuring circuit for each of the cells  100  to which it is connected. 
     As illustrated in  FIG. 9 , it also includes cut-outs that are intended to attach it to the studs  500  of the electrical energy storage cells  100 . 
     Consider an example of a cut-out  15  of the interconnection system  10 . This includes a straight interconnection jumper  11  which is extended at one end  19  by a connection eyelet  12 , and at the other end  18  forms a connection to the interconnection support  10 . This eyelet  12  is in the form of a circular arc whose opening angle (not shown) is facing the concave side of the cut-out  15 . 
     The interconnection eyelet  12  of the cut-out  15  slides sideways into the channel  570  formed by the two shoulders  520 ,  530  of the stud  502  of the cell  100  according to the invention. 
     More precisely, the opening angle of the eyelet  12  fits in a complementary manner around the shaft  510 , at the level of the aforementioned channel  570 , in order to allow the top surface  17  of the eyelet  12  to come into contact with the bottom part  521  of the primary shoulder  520  of the electrical connection stud  502 . 
     The opening angle of the eyelet  12  is designed to trap the eyelet  12  in position on the shaft  510 . 
     However there is a height difference between the bottom part  521  of the primary shoulder  520  of the electrical connection stud  502  and the top surface  17  of the interconnection eyelet  12  of the interconnection support  10 . 
     In order to bring them into in contact, the height difference is compensated for by means of the interconnection jumper  11 , which deforms by torsion. The length of the jumper  11  will be used to cope with a difference of altitude between the eyelet  12  and the support  10  while still allowing alignment of the eyelet  12  with the electrical connection stud  500 . 
     The spring element  70  described with reference to  FIGS. 6 and 7  also ensures contact between the electrical connection stud  502  and the interconnection eyelet  12 . 
     Those skilled in the art will be appreciative of an electrical energy storage cell  100  that offers a system for electrical connection through a sealing envelope  400  while still providing a precise electrical connection. 
     Moreover, this electrical energy storage cell  100  offers the advantage of providing a sealing system that is simple and effective. 
     Finally, an electrical energy storage cell  100  according to the invention proposes sealing and electrical connection system which, in relation to the known devices of the existing technology, can be used reliably for any assembly for the large-scale storage of electrical energy. As non-limiting examples, one can mention lithium-polymer, Nickel Metal Hydride or lithium-ion assemblies. 
     Naturally the present invention is not limited to the particular embodiments just described, but includes any variant that remains within its spirit. In particular, this present invention is not limited to the appended drawings. The specific references illustrated in the preceding paragraphs are non-limiting examples of the invention.