Hipot test apparatus for electrochemical cell assemblies and method for performing hipot tests on electrochemical cell assemblies

Abstract

A Hipot test apparatus for electrochemical cell assemblies comprises a power device (18) switchable between a test condition in which it is configured to deliver controlled voltages and an idle condition in which it delivers no currents; a plurality of test stations (10), wherein each test station (10) comprises a press (11) switchable between a test condition in which it exerts a compressive force on an electrochemical cell assembly (100) and an idle condition in which it exerts no compressive forces, each test station (10) further comprising a contacting area located at a corresponding press (11); at least one contacting assembly (13) switchable between a contacting condition in which it is arranged in the contacting area for making electrical contact with an electrochemical cell assembly (100) and an idle condition in which it is distanced from the contacting area; a movement system (12) configured to insert an electrochemical cell assembly (100) into a press (11) of a corresponding test station (10) and to remove an electrochemical cell (100) from a press (11) of a corresponding test station (10). The at least one contacting assembly (13) is placed in electrical connection with the power device (18) at least when the power device (18) is in the test condition; each test station (10) is switchable to a test condition wherein the press (11) is in the test condition, wherein the contacting assembly (13) is placed in the contacting condition and wherein the power device (18) is in the test condition; each test station (10) is switchable into a waiting condition wherein the contacting assembly (13) is in the idle condition. At the same time, at least one test station (10) is in the test condition and at least one further test station (10) is in the waiting condition.

Description

[0001] "Hipot test apparatus for electrochemical cell assemblies and method for performing Hipot tests on electrochemical cell assemblies"

[0002] DESCRIPTION

[0003] The present invention refers to a Hipot test apparatus for electrochemical cell assemblies and a method for performing Hipot tests on electrochemical cell assemblies.

[0004] The present invention finds a preferred, although not exclusive, application in the sector of the manufacture of electric accumulators that provide electrodes stacked one on top of the other with a separation layer in dielectric material interposed, generally indicated in the technical jargon of the sector with the term dielectric "separator".

[0005] The electrochemical cell assemblies can be produced in stacks of electrodes and dielectric separator that are electrically and physically joined together, usually in pairs, to be subsequently inserted in prismatic-shaped containers or in a bag.

[0006] Joining the stacks of electrodes and dielectric separator usually involves mechanically and electrically coupling together, for example through welding, the same type of poles (for example negative poles or positive poles) of two or more stacks using electrical connectors to define a positive electrical collector and a negative electrical collector. The electrical poles of each stack are usually placed on opposite sides of the stacks, where the ends of the electrodes are placed. The electric collectors used to join two or more stacks are therefore arranged at opposite side walls between which usually flat and continuous side walls develop.

[0007] A so-called Hipot (high potential) test can be performed on the electrochemical cell assemblies to determine the integrity of the electrochemical cells and in particular of the dielectric separator. During a Hipot test, controlled voltages are applied to the electrochemical cells for predetermined times and a leakage current is measured. The applied voltages are generally higher than the nominal voltage of the electrochemical cell to verify its ability to withstand overvoltages or voltage peaks that may occur under real operating conditions.

[0008] In some Hipot test applications, the electrochemical cell assemblies are subjected to a compressive action at the side walls that do not have electrical poles to further verify the ability to withstand overvoltages or voltage peaks.

[0009] In the Applicant's experience in an electrochemical cell assembly building line, the Hipot test station should be placed downstream of assembly stations of the electrochemical cell assemblies, such that the electrochemical cell assemblies may be subjected to Hipot test prior to being inserted into their respective containers.

[0010] The Applicant has observed that Hipot test operations on an electrochemical cell assembly requires execution times that are generally longer than the time required to assemble the electrochemical cell assembly. This difference between the time for the assembly of an electrochemical cell assembly and the execution of the Hipot test would require the presence of a buffer between the assembly station and the test station. However, this would negatively affect the overall dimensions and costs of the plant.

[0011] The Applicant has noted that the time to perform a Hipot test on an electrochemical cell assembly is given by a time when voltages are actually delivered to the electrochemical cell assembly and by further times required to insert the electrochemical cell assembly into the test station, to prepare it to receive these voltages, to prepare the electrochemical cell assembly to be removed from the test station and to remove it from the test station.

[0012] The Applicant has perceived that the test voltages could be delivered on an electrochemical cell assembly in a test station while in another test station another electrochemical cell assembly is being inserted (and possibly prepared to receive the test voltages) or such other electrochemical cell assembly is being prepared in order to be removed from the test station (and possibly removed). In this way, at least the time required to insert an electrochemical cell assembly into one test station (or to prepare the electrochemical cell assembly to be removed at one test station) can be used to deliver controlled voltages to another electrochemical cell assembly at another test station, increasing the production rate of electrochemical cell assemblies tested in the unit of time.

[0013] The Applicant has therefore found that by providing a plurality of test stations each provided with a respective press that can be activated and deactivated on an electrochemical cell assembly and a contacting assembly that can be activated and deactivated on an electrochemical cell assembly placed in a test station, in which at least one station is simultaneously active and at least one further test station is inactive and receives a further electrochemical cell assembly, it is possible to increase the production rate of electrochemical cell assemblies tested in the unit of time.

[0014] The present invention therefore relates, in a first aspect thereof, to a Hipot test apparatus for electrochemical cell assemblies. Preferably, the apparatus comprises a power device switchable between a test condition in which it is configured to deliver controlled voltages following a predetermined delivery law and an idle condition in which it delivers no currents.

[0015] Preferably, the apparatus comprises a plurality of test stations.

[0016] Preferably, each test station comprises a press switchable between a test condition in which it exerts a compressive force on an electrochemical cell assembly and an idle condition in which it exerts no compressive forces.

[0017] Preferably, each test station comprises a contacting area located at a corresponding press.

[0018] Preferably, the apparatus comprises at least one contacting assembly switchable between a contacting condition in which it is arranged in said contacting area for making electrical contact with an electrochemical cell assembly and an idle condition in which it is distanced from said contacting area.

[0019] Preferably, the apparatus comprises a movement system configured to insert an electrochemical cell assembly into a press of a related test station in a time Tb1 and to remove an electrochemical cell from a press of a related test station in a time Tb2.

[0020] Preferably, said at least one contacting assembly is placed in electrical connection with said power device at least when the power device is in the test condition.

[0021] Preferably, said at least one contacting assembly is configured to continuously remain in the contacting condition, with the power device in the test condition, for a time Ttest.

[0022] Preferably, said at least one contacting assembly is configured to switch from the idle condition to the contacting condition in a time Ta1 and is configured to switch from the contacting condition to the idle condition in a time Ta2.

[0023] Preferably, each test station is switchable to a test condition wherein said press is in the test condition, wherein said contacting assembly is placed in the contacting condition and wherein said power device is in the test condition.

[0024] Preferably, each test station is switchable into a waiting condition wherein said contacting assembly is in the idle condition.

[0025] Preferably, at the same time, at least one test station is in the test condition and at least one further test station is in the waiting condition.

[0026] Preferably, a cycle time Tc representative of the time elapsing between two successive activations of the movement system to remove an electrochemical cell assembly from a respective test station and a subsequent electrochemical cell assembly from a respective test station is less than Ta1 + Ta2 + Tb1 + Tb2 + Ttest.

[0027] The Applicant has verified that by providing at least one test station in the test condition and at least one further test station in the waiting condition, it is for example possible to perform the Hipot test on an electrochemical cell assembly while an already tested electrochemical cell assembly is picked from a further test station or while an electrochemical cell assembly to be tested is inserted into a further test station. By appropriately choosing the number of test stations as a function of the time required to prepare an electrochemical cell assembly for performing the Hipot test and as a function of the execution time of the Hipot test, it is possible to substantially set the production rate of electrochemical cell assemblies tested in the unit of time as desired.

[0028] The present invention relates, in a second aspect thereof, to a method for performing Hipot tests on electrochemical cell assemblies.

[0029] Preferably, it is provided for providing a plurality of test stations each comprising a press.

[0030] Preferably, it is provided for inserting an electrochemical cell assembly into a press of a test station.

[0031] Preferably, it is provided for switching said press into a test condition in which it exerts a compressive force on said electrochemical cell assembly.

[0032] Preferably, it is provided for contacting said electrochemical cell assembly with a contacting assembly.

[0033] Preferably, it is provided for delivering controlled voltages following a predetermined delivery law to said electrochemical cell assembly through said contacting assembly.

[0034] Preferably, it is provided for removing an electrochemical cell assembly to which controlled voltages have already been delivered from a press of a further test station while controlled voltages are delivered to said electrochemical cell assembly through said contacting assembly.

[0035] Preferably, it is provided for performing a first removal of an electrochemical cell assembly from a press of a test station to which controlled voltages have already been supplied and performing a second removal of an electrochemical cell assembly from a press of a further test station to which controlled voltages have already been supplied.

[0036] Preferably, a time Tc elapsing between said first removal and said second removal is less than: Ta1 + Ta2 + Tb1 + Tb2 + Ttest, where:

[0037] Ta1 represents a time for making electrical contact between a contacting assembly and an electrochemical cell assembly;

[0038] Ta2 represents a time for removing a contacting assembly from an electrochemical cell assembly;

[0039] Ttest represents a time for delivering controlled voltages following a predetermined delivery law to said electrochemical cell assembly;

[0040] Tb1 represents a time for inserting an electrochemical cell assembly into a press of a test station; and

[0041] Tb2 represents a time for removing an electrochemical cell assembly in a press of a test station.

[0042] The expression "electrochemical cell assembly" means, in the context of the present description and in the following claims, an assembly composed of at least one stack or of two or more stacks joined together, where each stack is made up of a plurality of electrodes (anode and cathode) alternated between them and separated by a dielectric separator. The electrodes are made of pieces of metallic material in sheet form and the dielectric separator can be a continuous strip arranged in a serpentine manner between the electrodes or a plurality of pieces in sheet form.

[0043] The term "horizontal" is used in the context of the present description and in the following claims in its common meaning, i.e. relative to a plane or a direction contained in a plane that is perpendicular to the vector of gravity acceleration. A horizontal plane is perpendicular to the direction according to which the plumb line is placed.

[0044] The term "vertical" is used in the context of the present description and in the following claims in its common meaning, i.e. relative to a plane or a direction contained in a plane that is parallel to the vector of gravity acceleration. A vertical plane contains the direction according to which the plumb line is placed.

[0045] The present invention may have at least one of the preferred features described below. Such features may therefore be present individually or in combination with each other, unless expressly stated otherwise, in any aspect of the present invention. Preferably, each test station comprises only one press.

[0046] Preferably, when said at least one contacting assembly is in the contacting condition, it is meant that said at least one contacting assembly is arranged in the contacting area of a related test station.

[0047] Preferably, when said at least one contacting assembly is in the idle condition, it is meant that said at least one contacting assembly is outside the contacting area of the corresponding test station.

[0048] Preferably, it is provided for removing or inserting an electrochemical cell assembly into a press of a corresponding test station only when the corresponding test station is in the waiting condition.

[0049] Preferably, the movement system is configured to insert or remove an electrochemical cell assembly in a press of a corresponding test station only when the corresponding test station is in the waiting condition.

[0050] Preferably, when a test station is in the waiting condition, the power device does not act on that test station.

[0051] Preferably, at the same time, at least one test station is in the test condition and at least one further test station is in the waiting condition means that there is at least one instant in which said at least one test station is in the test condition and said at least one further test station is in the waiting condition.

[0052] Ttest represents a delivery time of controlled voltages following a predetermined delivery law to an electrochemical cell assembly.

[0053] Preferably, when said at least one contacting assembly is in the contacting condition with the power device in the test condition for the time Ttest, an electrochemical cell assembly is arranged in the press of the corresponding test station and the press is in the test condition exerting a compressive force on the electrochemical cell assembly.

[0054] Preferably, a test station is in the test condition when said at least one contacting assembly is in the contacting condition with the power device in the test condition for the time Ttest.

[0055] Said at least one contacting assembly is configured to switch from the idle condition to the contacting condition in a time Ta1 . Preferably, Ta1 represents a time for making electrical contact between a contacting assembly and an electrochemical cell assembly.

[0056] Preferably, when said at least one contacting assembly switches from the idle condition to the contacting condition, the corresponding test station is in a contacting condition.

[0057] Preferably, in the contacting condition of a test station, an electrochemical cell assembly is arranged in the press of the test station and the press is in the test condition exerting a compressive force on the electrochemical cell assembly.

[0058] Preferably, in the contacting condition of a test station, the power device delivers no voltages to the electrochemical cell assembly located in the test station.

[0059] Said at least one contacting assembly is configured to switch from the contacting condition to the idle condition in a time Ta2.

[0060] Preferably, Ta2 represents a time for removing a contacting assembly from an electrochemical cell assembly.

[0061] Preferably, when said at least one contacting assembly switches from the contacting condition to the idle condition, the corresponding test station is in a decontacting condition.

[0062] Preferably, in the de-contacting condition of a test station, an electrochemical cell assembly is arranged in the press of the test station and the press is in the test condition exerting a compressive force on the electrochemical cell assembly.

[0063] Preferably, in the de-contacting condition of a test station, the power device delivers no voltages to the electrochemical cell assembly located in the test station.

[0064] Said movement system is configured to insert an electrochemical cell assembly into a press in a time Tb1 .

[0065] Preferably, Tb1 represents a time for inserting an electrochemical cell assembly into a press of a test station.

[0066] Preferably, when said movement system inserts an electrochemical cell assembly into a press of a test station, the test station is in the waiting condition and the press is in the idle condition in which it exerts no compressive forces on the electrochemical cell assembly.

[0067] Preferably, when said movement system inserts an electrochemical cell assembly into a press of a test station, the contacting assembly is in the idle condition.

[0068] Said movement system is configured to remove an electrochemical cell assembly from a press in a time Tb2.

[0069] Preferably, Tb2 represents a time for removing an electrochemical cell assembly in a press of a test station.

[0070] Preferably, when said movement system removes an electrochemical cell assembly in a press of a test station, the test station is in the waiting condition and the press is in the idle condition in which it exerts no compressive forces on the electrochemical cell assembly.

[0071] Preferably, when said movement system removes an electrochemical cell assembly in a press of a test station, the contacting assembly is in the idle condition.

[0072] Preferably, a residence time Tper of an electrochemical cell assembly in the test apparatus is equal to Ta1 + Ta2 + Tb1 + Tb2 + Ttest.

[0073] Preferably, Tper represents a time elapsing between insertion (including insertion time) and removal (including removal time) of an electrochemical cell assembly in a test station.

[0074] Preferably, said second removal is immediately subsequent to said first removal. Preferably, no further removal is provided between said first removal and said second removal.

[0075] Preferably, Tc is representative of the production rate of electrochemical cell assemblies tested.

[0076] Preferably, Tc coincides with the feed rate of electrochemical cell assemblies to the test apparatus.

[0077] Preferably, Ta1 , Ta2, Tb1 , Tb2, Ttest and Tc are expressed in seconds.

[0078] By way of example, when Tc is equal to 5 seconds, the production rate of electrochemical cell assemblies tested is 1 electrochemical cell assembly every 5 seconds. In this example, it is possible to feed the test apparatus 1 with an electrochemical cell assembly every 5 seconds without having to provide for an accumulation buffer at the entry to the test apparatus.

[0079] Preferably, said plurality of test stations comprises a number N test stations, where N is an integer greater than or equal to two.

[0080] Preferably, the number of presses is equal to N.

[0081] Preferably, said at least one contacting assembly comprises a number G contacting assemblies, where G is an integer less than or equal to N.

[0082] By choosing the number N of test stations and the number G of contacting assemblies it is possible to define the known cycle time Tc and the test time Ttest.

[0083] The power device may comprise a single electric power supply for all contacting assemblies, or an electric power supply for each contacting assembly or a plurality of electric power supplies each of which is subservient to a plurality of contacting assemblies.

[0084] In a first embodiment, preferably said number G of contacting assemblies is equal to the number N of test stations decreased by two and the number N of test stations is greater than or equal to three.

[0085] By way of example, 3 test stations and 1 contacting assembly, 4 test stations and 2 contacting assemblies, 7 test stations and 5 contacting assemblies may be provided.

[0086] Preferably, in the first embodiment the number N of test stations is provided by the integer that approximates the result by excess from the formula N = ( 2*Tc + Ttest + Ta1 + Ta2 ) I Tc; wherein Tb1 and Tb2 are less than or equal to Tc.

[0087] By way of example, in the case where the cycle time Tc is 4 seconds, the test time Ttest is 5 seconds, the contacting time Ta1 is 0.5 seconds and the decontacting time is 0.5 seconds, the number N of test stations is 4 (the above formula having 3.5 as a result).

[0088] In this example, the production rate of tested electrochemical cell assemblies is 1 electrochemical cell assembly tested every 4 seconds (Tc), wherein the controlled voltage delivery time to perform a test (Ttest) is 5 seconds and wherein the time for contacting and de-contacting an electrochemical cell assembly is 0.5 seconds, respectively. In this example, the time for inserting or removing an electrochemical cell assembly from a respective test station must not exceed 4 seconds.

[0089] Therefore, in this example it is possible to continuously feed 1 electrochemical cell assembly every 4 seconds to the test apparatus without having to provide for an accumulation buffer at the entry to the test apparatus, since 1 electrochemical cell assembly tested every 4 seconds is produced (processed). This despite the fact that the test time required to deliver controlled currents to a set of tests is 5 seconds.

[0090] In the first embodiment, preferably at the same time, at least one test station is in the test condition and at least two further test stations are in the waiting condition.

[0091] In the first embodiment, preferably at least two test stations are simultaneously in the waiting condition.

[0092] In the first embodiment, preferably only one movement system is provided.

[0093] In this way, it is possible to reduce the complexity, costs and overall dimensions of the test apparatus.

[0094] Preferably, inserting an electrochemical cell assembly into a press of a test station is implemented prior to or subsequent to removing an electrochemical cell assembly from a press of a further test station.

[0095] Preferably, the movement system is configured to insert an electrochemical cell assembly into a test station and to remove an electrochemical cell assembly from a test station at different times.

[0096] In the first embodiment, it is provided for contacting N-2 electrochemical cell assemblies with G contacting assemblies.

[0097] In the first embodiment, preferably the test stations that are simultaneously in the test condition are at least N-2 when Ta1 is less than Ttest.

[0098] In the first embodiment, preferably delivering controlled voltages following a predetermined delivery law to said electrochemical cell assembly through said contacting assembly is implemented simultaneously on a number of electrochemical cell assemblies equal to the number of test stations decreased by two. In the first embodiment, it is preferably provided for delivering controlled voltages following a predetermined delivery law simultaneously with the number of electrochemical cell assemblies equal to the number of test stations decreased by two and, at the same time, it is provided for removing an electrochemical cell assembly from a test station that is not receiving voltages.

[0099] In the first embodiment, it is preferably provided for delivering controlled voltages following a predetermined delivery law simultaneously with the number of electrochemical cell assemblies equal to the number of test stations decreased by two and, at the same time, it is provided for inserting an electrochemical cell assembly from a test station that is not receiving voltages.

[0100] In the first embodiment, preferably a same contacting assembly is configured to operate, at different times, on more than one test station.

[0101] In the first embodiment, preferably a same contacting assembly is associated with more than one test station.

[0102] Preferably, in the first embodiment a same contacting assembly is associated with at least two test stations.

[0103] Preferably, when a contacting assembly is in the contacting condition in a test station, said contacting assembly is simultaneously in the idle condition of a further test station.

[0104] In the numerical example above, two contacting assemblies are provided each of which serve two test stations. In this example, when a contacting assembly is in the contacting condition in a first test station, that contacting assembly is simultaneously in the idle condition in a second test station.

[0105] In a second embodiment, preferably said number G of contacting assemblies is equal to the number N of test stations.

[0106] In the second embodiment, preferably the number N of test stations is provided by the integer that approximates the result by excess from the formula: N = ( Tb1 + Tb2 + Ttest + Ta1 + Ta2 ) I Tc; wherein Tb1 and Tb2 must be less than Tc.

[0107] By way of example, in the case where the cycle time Tc is 4 seconds, the test time Ttest is 5 seconds, the contacting time Ta1 is 0.5 seconds and the decontacting time is 0.5 seconds, the number N of test stations is 2 (the above formula resulting in 2.0). In this example, the production rate of tested electrochemical cell assemblies is 1 electrochemical cell assembly tested every 4 seconds (Tc), wherein the controlled voltage delivery time to perform a test (Ttest) is 5 seconds and wherein the time for contacting and de-contacting an electrochemical cell assembly is 0.5 seconds, respectively.

[0108] Therefore, in this example it is possible to continuously feed 1 electrochemical cell assembly every 4 seconds to the test apparatus without having to provide for an accumulation buffer at the entry to the test apparatus, since 1 electrochemical cell assembly tested every 4 seconds is produced (processed). This despite the fact that the test time required to deliver controlled currents to a set of tests is 5 seconds.

[0109] In the second embodiment, preferably at the same time, at least one test station is in the test condition and at least one further test station is in the waiting condition.

[0110] In the first embodiment, preferably only one movement system is provided.

[0111] In this way, it is possible to reduce the complexity, costs and overall dimensions of the test apparatus.

[0112] Preferably, inserting an electrochemical cell assembly into a press of a test station is performed prior to removing an electrochemical cell assembly from a press of a further test station.

[0113] Preferably, the movement system is configured to insert an electrochemical cell assembly into a test station and to remove an electrochemical cell assembly from a test station at different times.

[0114] In the second embodiment, it is provided for contacting N electrochemical cell assemblies with G contacting assemblies.

[0115] In the second embodiment, preferably the contacting assemblies that are simultaneously in the contacting condition are equal to or greater than N-1 .

[0116] In the second embodiment, it is preferably provided that the number of contacting assemblies simultaneously in the contacting condition is equal to the number of test stations decreased by one and that, simultaneously, a test station is in the waiting condition. In the second embodiment, preferably delivering controlled voltages following a predetermined delivery law to said electrochemical cell assembly through said contacting assembly is implemented simultaneously on a number of electrochemical cell assemblies equal to or greater than the number of test stations decreased by two.

[0117] In the second embodiment, it is preferably provided for delivering controlled voltages following a predetermined delivery law simultaneously with the number of electrochemical cell assemblies equal to or greater than the number of test stations decreased by two and, at the same time, it is provided for removing an electrochemical cell assembly from a test station that is not receiving voltages.

[0118] In the second embodiment, it is preferably provided for delivering controlled voltages following a predetermined delivery law simultaneously with the number of electrochemical cell assemblies equal to or greater than the number of test stations decreased by two and, at the same time, it is provided for inserting an electrochemical cell assembly from a test station that is not receiving voltages.

[0119] In the second embodiment, preferably each contacting assembly is configured to operate on a single respective test station.

[0120] In all embodiments, preferably each press comprises a first plate and a second plate switchable between the test condition in which the first plate is approached to the second plate to exert a compressive force on an electrochemical cell assembly and the idle condition in which the first plate is distanced from the second plate.

[0121] Preferably, the first plate can be approached and distanced from the second plate along a working direction contained in a horizontal plane.

[0122] The Applicant has found that in this way it is possible to insert the electrochemical cell assembly from above inside the press by contacting the upper wall or the lower wall of the electrochemical cell assembly (both not affected by the electrical connectors). In this way, the electrochemical cell assembly is not subjected to sliding against the plates of the press, is not contacted at the electrical connectors and it is possible to shape the plates of the press in such a way as to be able to apply as uniform a pressure as possible on the two side walls of the electrochemical cell assembly.

[0123] Preferably, the electrochemical cell assembly is substantially prismatic in shape. Preferably, the electrochemical cell assembly comprises a base, a top and four sides arranged substantially orthogonal to each other and orthogonal to the base and the top.

[0124] Preferably, two mutually parallel sides comprise respective flat and substantially continuous side walls.

[0125] Preferably, two further mutually parallel sides each comprise an electrical connector made of electrically conductive material.

[0126] Preferably, the top comprises a lid comprising two electric poles made of electrically conductive material.

[0127] Preferably, each electrical pole is mechanically and electrically connected to a respective electrical connector.

[0128] Preferably, the first plate can be approached and distanced from the second plate only along a working direction contained in a horizontal plane.

[0129] Preferably, the first plate and the second plate of the press comprise respective contact surfaces configured to contact the side walls of the electrochemical cell assembly, said contact surfaces being flat and continuous surfaces.

[0130] The contact surfaces of the first and second presses are preferably facing each other.

[0131] The contact surfaces of the first and second presses are preferably parallel to each other.

[0132] The contact surfaces of the first and second presses are contained in a vertical plane when in the test condition.

[0133] The contact surfaces of the first and second presses are contained in a vertical plane when in the idle condition.

[0134] Preferably, said movement system is switchable between a grasping condition and a release condition.

[0135] Preferably, in said grasping condition said movement system is configured to retain an electrochemical cell assembly at a wall not contacted by said press.

[0136] Preferably, in said grasping condition said movement system is configured to retain the electrochemical cell assembly at the top of the electrochemical cell assembly.

[0137] Preferably, in said grasping condition said movement system is configured to retain the electrochemical cell assembly at the lid of the electrochemical cell assembly.

[0138] The Applicant has verified that by retaining the electrochemical cell assembly at the top, the electrochemical cell assembly is arranged substantially vertically, i.e. with the side walls arranged vertically.

[0139] Preferably, inserting an electrochemical cell assembly into a press of a test station comprises moving the electrochemical cell assembly in a vertical direction to bring it into the press.

[0140] Preferably, said movement system is configured to translate the electrochemical cell assembly between the first plate and the second plate of the press in a vertical direction.

[0141] Preferably, said movement system is switchable in the release condition when said first plate is approached to the second plate.

[0142] Preferably, subsequent to positioning the electrochemical cell assembly between the first plate and the second plate it is provided for approaching the first plate to the second plate until a compressive force is applied to the side walls of the electrochemical cell assembly.

[0143] In this way, the electrochemical cell assembly remains inside the press, positioned vertically, without the need to rest the base of the electrochemical cell assembly on any support. The compressive force exerted by the first plate and the second plate of the cell in fact prevents the electrochemical cell assembly from being able to translate vertically with respect to the press.

[0144] Preferably, subsequent to applying a compressive force to the side walls of the electrochemical cell assembly it is provided for releasing the electrochemical cell assembly.

[0145] Preferably, removing an electrochemical cell assembly, to which controlled voltages have already been delivered, from a press comprises retaining the electrochemical cell assembly while it is being compressed between the first plate and the second plate.

[0146] The movement system is configured to be switched into the grasping condition when said first plate is still approached to the second plate.

[0147] Subsequent to retaining the electrochemical cell assembly while it is being compressed between the first plate and the second plate it is preferably provided for distancing the first plate from the second plate.

[0148] The movement system switched in the grasping condition prevents the electrochemical cell assembly from being able to move vertically and falling when the first plate is distanced from the second plate.

[0149] Preferably, when an electrochemical cell assembly is retained by the movement system and the electrochemical cell assembly is arranged between the first plate and the second plate, no contacting assembly is arranged in the contacting area of the test station.

[0150] Further features and advantages of the present invention will be better apparent from the following detailed description of a preferred embodiment thereof, with reference to the appended drawings and provided by way of indicative and nonlimiting example, wherein:

[0151] Figure 1 is a schematic view of some parts of a Hipot test apparatus for electrochemical cell assemblies in accordance with the present invention;

[0152] Figures 2 and 3 are schematic views of the parts of Figure 1 in different operating conditions;

[0153] Figures 4 and 5 are schematic views of possible layouts of the apparatus of Figure 1 ;

[0154] Figures 6 to 9 are schematic views of an operation of the apparatus of Figure 1 in accordance with a first embodiment;

[0155] Figures 10 to 12 are schematic views of an operation of the apparatus of Figure 1 in accordance with a second embodiment; and

[0156] Figure 13 is a schematic view of an electrochemical cell assembly.

[0157] The representations in the accompanying figures do not necessarily have to be understood in scale and do not necessarily respect the proportions between the various parts.

[0158] In Figure 13, an electrochemical cell assembly has been indicated as a whole with number 100 which can be subjected to Hipot test in a Hipot test apparatus in accordance with the present invention.

[0159] The electrochemical cell assembly 100 illustrated in Figure 13 is composed of two stacks joined together, however it could be made from a single stack. The electrochemical cell assembly 100 comprises a base 101 , a top 102, and four sides arranged substantially orthogonal to each other and orthogonal to the base 101 and the top 102. The four sides comprise two larger sides defining two side walls 103 parallel to each other. The two side walls 103 extend from the base 101 to the top 102. Between the two side walls 103 there are placed electrical connectors 104 made of conductive material each of which connected to respective electrodes (not depicted) placed in the electrochemical cell assembly.

[0160] At the top 102 a substantially flat lid 105 is placed and provided with two electrical poles 106 each of which is connected to a respective electrical connector 104. The side walls 103 extend until contacting the lid 105. The electrodes of the electrochemical cell assembly are placed immediately below the lid 105 and slightly spaced from the latter. The electrodes extend substantially up to the base 101.

[0161] The two side walls 103 are flat and continuous. A winding strip 107 (indicated in dotted line in Figure 13) externally wraps the two side walls 103 and the base 101. The strip 107 reaches, without contacting it, the lid 105. The electrical connectors 104 are preferably covered by inserts (not illustrated) of non- conductive material. The electrochemical cell assembly 100 is configured to be inserted into a prismatic container or a bag to make a battery.

[0162] In Figure 1 , a portion of a Hipot test apparatus in accordance with the present invention is indicated with number 1. The apparatus 1 is also schematically represented in Figures 4 and 5 in two possible layouts that will be discussed below.

[0163] The apparatus 1 comprises a plurality of test stations 10 each provided with a press 11 .

[0164] Apparatus 1 further comprises a movement system 12 for an electrochemical cell assembly 100 and at least one contacting assembly 13.

[0165] As schematized in Figure 1 , each press 11 comprises a first plate 14 and a second plate 15 placed facing each other in such a way as to define an empty space S between them. The first plate 14 comprises a flat and continuous contact surface 16. In the preferred embodiment of the invention, the contact surface 16 is arranged along a vertical plane. The second plate 15 also comprises a flat and continuous contact surface 17. The contact surface 17 is arranged along a vertical plane and is parallel to the contact surface 16 of the first plate 14. The contact surfaces 16, 17 face each other directly.

[0166] The first plate 14 and the second plate 15 are both movable toward and away from each other along a horizontal direction. The first plate 14 and the second plate 15 are movable between an idle condition and a test condition. In the idle condition the first plate 14 and the second plate 15 are more distant from each other than in the test condition. A movement device, for example hydraulic (not shown), moves the first plate 14 and the second plate 15. The contact surfaces 16, 17 of the first plate 14 and the second plate 15 are larger than the side walls 103 of the electrochemical cell assembly.

[0167] The at least one contacting assembly 13 is placed in electrical connection with a power device 18 configured to deliver voltages controlled over time and in intensity. The power device 18 is configured to deliver voltages greater than the nominal voltage of the electrochemical cell assembly 100 for a period of time comprised between 10 seconds and 10 minutes. The at least one contacting assembly 13 comprises a pair of contacting plates 19 each configured to mechanically and electrically contact a respective electrical pole 106 of the electrochemical cell assembly 100. The contacting assembly 13 is made movable so as to be switched between a contacting condition in which the contacting plates 19 contact the electric poles 106 of the electrochemical cell assembly 100 and an idle condition in which the contacting plates 19 contact the electric poles 106 of the electrochemical cell assembly 100. The contacting assembly 13 is placed in electrical connection with the power device 18 at least when the contacting assembly 13 is in the contacting condition.

[0168] The movement system 12 comprises a movement head 20 kinematically connected with an actuator 21 , for example an electric motor, through, for example, an articulated arm 22 (schematized in Figure 1 ). The movement head 20 comprises a suction device 23 configured to generate a depression. The suction device 23 comprises a plurality of suction heads 24 placed at a lower end of the movement head 20, as schematically illustrated in Figure 1 . The movement system 12 is configured to grasp an electrochemical cell assembly 100 at the lid 105. In particular, the suction heads 24 are configured to contact the lid 105 of the electrochemical cell assembly 100 and to retain (when the suction device 23 is activated) the electrochemical cell assembly 100 in contrast to the force of gravity. The movement system 12 is configured to move the electrochemical cell assembly 100 in space when it is grasped by the suction heads 24. In particular, the movement system 12 is configured to move the electrochemical cell assembly 100 at least in a vertical direction when it is grasped by the suction heads 24.

[0169] Figures 2 and 3 schematically illustrate the insertion of an electrochemical cell assembly 100 into a press 11 of a test station 10. The electrochemical cell assembly 100 is grasped and positioned vertically above the press 11 .

[0170] This operation is performed by placing the movement head 20 of the movement system 12 at the lid 105 of the electrochemical cell assembly 100. The suction heads 24 are placed on the lid 105 and the suction device 23 is activated. The electrochemical cell assembly 100 is then retained in a vertical position supported by the movement system 12. The contacting assembly 13 is in the idle condition and the press 11 is in the idle condition (as illustrated in Figure 1 ).

[0171] Subsequently, the movement system 12 vertically translates the electrochemical cell assembly 100 in the press 11 between the first plate 14 and the second plate 15. This operation is performed by inserting the electrochemical cell assembly 100 into the empty space S between the first plate 14 and the second plate 15. The first plate 14 and the second plate 15 are in the idle condition. The contacting assembly 13 is in the idle condition. The electrochemical cell assembly 100 is retained in a vertical position supported by the movement system 12.

[0172] Subsequently or simultaneously, the first plate 14 and the second plate 15 are approached horizontally. Only when the movement system 12 stops the vertical descent of the electrochemical cell assembly 100, the first plate 14 and the second plate 15 reach the test condition. In this condition, the first plate 14 and the second plate 15 exert a compressive action on the side walls 103 of the electrochemical cell assembly 100. The movement system 12 places the electrochemical cell assembly 100 in such a position that the lid 105 is placed outside the action of the contact surfaces 16, 17 of the first plate 14 and the second plate 15. Thus, in the test condition, the contact surfaces 16, 17 of the first plate 14 and the second plate 15 do not contact the lid 105 of the electrochemical cell assembly 100. The movement system 12 places the electrochemical cell assembly 100 in such a position that the contact surfaces 29, 34 of the first slider 25 and the second slider 25 do not contact the lid 105 of the electrochemical cell assembly 100. The contacting assembly 13 is in the idle condition, as schematically illustrated in Figure 2.

[0173] When the first plate 14 and the second plate 15 exert the aforementioned compressive action on the side walls 103 of the electrochemical cell assembly 100, the movement system 12 releases the electrochemical cell assembly 100 and moves away from the press 11. The electrochemical cell assembly 100 remains tightened in the press 11 and remains in the position reached without being able to translate vertically due to the effect of friction between the side walls 103 and the contact surfaces 16, 17 of the first plate 14 and the second plate 15. Subsequently or simultaneously, the contacting assembly 13 is placed in the contacting condition, as schematized in Figure 3. The contacting plates 19 contact the electrical poles 106 of the electrochemical cell assembly 100.

[0174] To remove an electrochemical cell assembly from a press 11 , the contacting assembly is moved into the idle condition.

[0175] When the contacting assembly reaches the idle condition, the movement system 12 grasps the electrochemical cell assembly 100.

[0176] This operation is performed by placing the movement head 20 of the movement system 12 at the lid 105 of the electrochemical cell assembly 100. The suction heads 24 are placed on the lid 105 and the suction device 23 is activated. The electrochemical cell assembly 100 is thus retained. The press 11 is in the test condition.

[0177] Subsequently or simultaneously, the first plate 14 and the second plate 15 are distanced horizontally. The first plate 14 and the second plate 15 progressively decrease the compressive action on the side walls 103 of the electrochemical cell assembly 100 until they return to the idle condition. In this condition the first plate 14 and the second plate 15 exert no compressive action on the electrochemical cell assembly. During these actions, the movement system 12 continues to retain the electrochemical cell assembly 100.

[0178] When the first plate 14 and the second plate 15 reach the idle position, the movement system lifts the electrochemical cell assembly 100 by translating it vertically. This operation causes the electrochemical cell assembly to exit from the press 11 .

[0179] Figure 4 schematically depicts a first possible configuration of the apparatus 1 .

[0180] In this configuration, the test stations 10 are mounted on a fixed structure 25. The test stations 10 are mounted stationary on the structure 25. The movement system 12 is preferably only one and is placed in a movement relationship with the test stations 10 in such a way as to be able to reach the press 11 of any test station 10. The contacting assemblies 13 are made movable with respect to the test stations 10 in such a way that each contacting assembly 13 can enslave more than one test station 10. In particular, each contacting assembly 13 may alternatively enslave two test stations 10 in such a way as to be able to place itself in the contacting condition alternately on both test stations 10. In an embodiment variant not illustrated, a contacting assembly 13 is provided for each test station 10.

[0181] A second possible configuration of the apparatus 1 is schematically depicted in Figure 5.

[0182] In this configuration, the test stations 10 are mounted on a movable, preferably rotatable, structure 25. The test stations 10 are mounted stationary on the movable structure 25. The movement system 12 is preferably only one and is positioned in such a way that it can reach the press 11 of two test stations 10. The contacting assemblies 13 are made movable with respect to the test stations 10 and with respect to the structure 25 in such a way that each contacting assembly 13 can enslave more than one test station 10. In particular, each contacting assembly 13 may be placed in the contacting condition on a test station 10 and remain in that condition on the test station 10 while the structure 25 rotates. In an embodiment variant not illustrated, a contacting assembly 13 is provided for each test station 10 that moves synchronously with the test station 10.

[0183] In both possible configurations, the power device 18 comprises at least an electric power supply 26 (schematically depicted in Figure 1 ). In some embodiments, the electric power supply 26 is one and supplies voltage to all of the contacting assemblies. In other embodiments, a plurality of electric power supplies 26 are provided, for example one or more for each contacting assembly 13 or each for a plurality of contacting assemblies 13. The choice of the number of electric power supplies 26 depends on the powers actually delivered by the power device 18.

[0184] Figures 6 to 9 schematically show a first embodiment of the apparatus 1 at different time points during a Hipot test on a plurality of electrochemical cell assemblies 100 and Figures 10 to 12 schematically show a second embodiment of the apparatus 1 at different time points during a Hipot test on a plurality of electrochemical cell assemblies 100.

[0185] In both embodiments, and therefore in all Figures from 6 to 12, the action of inserting an electrochemical cell 100 into a press 11 of a test station 10 was represented with an arrow pointing downwards. This insertion is performed, for example, according to the manners described above. Tb1 represents the time in seconds required to complete the insertion of an electrochemical cell 100 into a press 11 of a test station 10. The time Tb1 can be considered a design data as it is directly a function of the type of movement system 12 used and the type of presses 11 used. The action of removing an electrochemical cell 100 from a press 11 of a test station 10 was represented with an arrow pointing upwards. This removal is performed, for example, according to the manners described above. Tb2 represents the time in seconds required to complete the removal of an electrochemical cell 100 from a press 11 of a test station 10. The time Tb1 can be considered a design data as it is directly a function of the type of movement system 12 used and the type of presses 11 used. The contacting or de-contacting action of a contacting assembly 13 from the contacting area of a test station 10 was represented with an empty circle. Ta1 represents the time in seconds required to position a contacting assembly 13 in the contacting area and to contact an electrochemical cell assembly 100 inserted in the press 11 of a test station 10. The time Ta1 can be considered a design data as it is directly a function of the type of contacting assemblies 13 used. Ta2 represents the time in seconds required to de-contact an electrochemical cell assembly 100 inserted in the press 11 of a test station 10 and to remove the contacting assembly 13 from the contacting area of the test station 10. The time Ta2 can be considered a design data as it is directly a function of the type of contacting assemblies 13 used. The action of delivering controlled voltages to an electrochemical cell assembly 100 inserted in a press 11 of a test station 10 was represented with a solid circle (illustrated in black). Ttest represents the total time of the action of delivering controlled voltages to an electrochemical cell assembly 100. The Ttest test time is a design parameter linked to the type of test to be performed. Two successive figures represent the apparatus 1 at two different time points and temporally distanced from each other by a cycle time Tc. The cycle time Tc represents the time elapsing between a removal of one electrochemical cell assembly from the apparatus 1 and a subsequent removal of another electrochemical cell assembly from the apparatus 1 . The cycle time Tc measures in seconds the production rate of an electrochemical cell assembly tested by the apparatus 1. The time Tc can be chosen according to specific needs. For example, the time Tc can be chosen identical to the time elapsing between the feeding, or making available, of two electrochemical cell assemblies by an apparatus placed upstream of the apparatus 1 , in such a way as to eliminate the need to provide buffers for electrochemical cell assemblies between the two apparatuses.

[0186] In the first embodiment illustrated in Figures 6 to 9, the number N of test stations is equal to: N = ( 2*Tc + Ttest + Ta1 + Ta2 ) / Tc, where N is an integer that approximates the result of the formula by excess. As can be appreciated from the formula, the insertion time Tb1 and the removal time Tb2 are not relevant in the calculation of the number of test stations 10. However, both the insertion time Tb1 and the removal time Tb2 must be less than the cycle time Tc.

[0187] In this embodiment, the number G of contacting assemblies is equal to the number of test stations decreased by two.

[0188] In the example illustrated in Figure 6 to 9, the design parameters of the apparatus 1 envisage that Ta1 = 0.5 seconds, Ta2 = 0.5 seconds, Tb1 = 1 second, Tb2 = 1 second and Ttest = 5 seconds. The cycle time Tc was set to 3 seconds so as to have an electrochemical cell assembly tested and removed from the apparatus every 3 seconds. By applying the above formula, the number of test stations 10 is equal to four and the number of contacting assemblies 13 is equal to two.

[0189] Figure 6 illustrates a first temporal moment of the duration Tc (3 seconds in the specific example) in which a first test station 10a is in the waiting condition and in which an electrochemical cell assembly is inserted into the press 11 of the first test station 10a according to the manners described above. The electrochemical cell assembly is inserted into the press 11 of the first test station 10a engaging the movement system 12 for a time Tb1 of 1 second. During this time the movement system 12 is not available for the removal of electrochemical cell assemblies. After insertion of the electrochemical cell assembly into the first test station 10a, the first test station 10a remains for a further two seconds in the waiting condition with the corresponding press 11 in the test condition. At the same first temporal moment of duration Tc, in a second test station 10b in the waiting condition and with the corresponding press in the test condition and in which an electrochemical cell assembly had previously been inserted, a first contacting assembly 13a of the two contacting assemblies 13 is made available. In the time Ta1 of 0.5 seconds the first contacting assembly 13a is placed in the contacting condition in the contacting area of the second test station 10b. Immediately thereafter, the power device 18 is activated on the first contacting assembly 13a which is placed in the contacting condition. The second test station 10b is therefore in the test condition and remains in that condition for the remaining duration (2.5 seconds) of the first temporal moment. At the same first temporal moment of duration Tc, a third test station 10c is in the test condition engaging the second contacting assembly 13b of the two contacting assemblies 13. The third test station 10c remains in the test condition for 2.5 seconds. After this time, the power device 18 interrupts the delivery of voltage to the electrochemical cell assembly present in the third test station 10c. The second contacting assembly 13b is de-contacted from the third test station 10c in a time Ta2 of 0.5 seconds. The third test station 10c is therefore in the waiting condition with the corresponding press in the test condition. The second contacting assembly 13b is made available. At the same first temporal moment of duration Tc, a fourth test station 10d is in the waiting condition with the press in the test condition and with an electrochemical cell assembly already subjected to Hipot test. The fourth test station 10d remains in this condition for the time Tb1 (1 second) in which the movement system 12 is not available. After this time, the movement system 12 removes the electrochemical cell assembly from the fourth station 10d which therefore remains empty (i.e. without any electrochemical cell assembly inserted therein).

[0190] Figure 7 illustrates a second temporal moment of the duration Tc (3 seconds in the specific example) in which the second contacting assembly 13b of the two contacting assemblies 13 is made available in the first test station 10a. In the time Ta1 of 0.5 seconds the second contacting assembly 13b is placed in the contacting condition in the contacting area of the first test station 10a. Immediately thereafter, the power device 18 is activated on the second contacting assembly 13b and the first test station 10a is therefore in the test condition and remains in that condition for the remaining duration (2.5 seconds) of the second temporal moment. At the same second temporal moment of duration Tc, the second test station 10b is in the test condition engaging the first contacting assembly 13a of the two contacting assemblies 13. The second test station 10b remains in the test condition for 2.5 seconds. After this time, the power device 18 interrupts the delivery of voltage to the electrochemical cell assembly present in the second test station 10b. The first contacting assembly 13a is de-contacted from the second test station 10b in a time Ta2 of 0.5 seconds. The second test station 10b is therefore in the waiting condition. The first contacting assembly 13a is made available. At the same second temporal moment of duration Tc, the third test station 10c is in the waiting condition with the press in the test condition and with an electrochemical cell assembly already subjected to Hipot test. The third test station 10d remains in this condition for the time Tb1 (1 second) in which the movement system 12 is not available. After this time, the movement system 12 removes the electrochemical cell assembly from the third station 10c which therefore remains empty (i.e. without any electrochemical cell assembly inserted therein). At the same second moment in time, the fourth test station 10d is in the waiting condition and an electrochemical cell assembly is inserted into the corresponding press 11. The electrochemical cell assembly is inserted into the fourth test station 10d engaging the movement system 12 for a time Tb1 of 1 second. During this time the movement system 12 is not available for the removal of electrochemical cell assemblies. After the electrochemical cell assembly is inserted into the fourth test station 10d, the fourth test station 10d remains in the waiting condition for a further two seconds.

[0191] Figure 8 illustrates a third temporal moment of the duration Tc (3 seconds in the specific example) in which the first test station 10a is in the test condition engaging the second contacting assembly 13b. The first test station 10a remains in the test condition for 2.5 seconds. After this time, the power device 18 interrupts the delivery of voltage to the electrochemical cell assembly present in the first test station 10a. The second contacting assembly 13b is de-contacted from the first test station 10a in a time Ta2 of 0.5 seconds. The first test station 10a is therefore in the waiting condition. The second contacting assembly 13b is made available. At the same third temporal moment of duration Tc, the second test station 10b is in the waiting condition with the press in the test condition and with an electrochemical cell assembly already subjected to Hipot test. The second test station 10b remains in this condition for the time Tb1 (1 second) in which the movement system 12 is not available. After this time, the movement system 12 removes the electrochemical cell assembly from the second test station 10b, which is then empty. At the same third temporal moment of duration Tc, the third test station 10c is in the waiting condition and an electrochemical cell assembly is inserted into the corresponding press 11 . The electrochemical cell assembly is inserted into the third test station 10c engaging the movement system 12 for a time Tb1 of 1 second. During this time the movement system 12 is not available for the removal of electrochemical cell assemblies. After insertion of the electrochemical cell assembly into the third test station 10c, the third test station 10c remains in the waiting condition for a further two seconds. At the same third temporal moment of duration Tc, in the fourth test station 10d the first contacting assembly 13a is made available. In the time Ta1 of 0.5 seconds the first contacting assembly 13a is placed in the contacting condition in the contacting area of the fourth test station 10d. Immediately thereafter, the power device 18 is activated on the first contacting assembly 13a and the fourth test station 10d is therefore in the test condition and remains in that condition for the remaining duration (2.5 seconds) of the third temporal moment.

[0192] Figure 9 illustrates a fourth temporal moment of the duration Tc (3 seconds in the specific example) in which the first test station 10a is in the waiting condition with the press in the test condition and with an electrochemical cell assembly already subjected to Hipot test. The first test station 10a remains in this condition for the time Tb1 (1 second) in which the movement system 12 is not available. After this time, the movement system 12 removes the electrochemical cell assembly from the first test station 10a, which is then empty. At the same fourth temporal moment of duration Tc, the second test station 10b is in the waiting condition and an electrochemical cell assembly is inserted into the corresponding press 11 . The electrochemical cell assembly is inserted into the second test station 10b engaging the movement system 12 for a time Tb1 of 1 second. During this time the movement system 12 is not available for the removal of electrochemical cell assemblies. After insertion of the electrochemical cell assembly into the second test station 10b, the second test station 10b remains for a further two seconds in the waiting condition. At the same fourth temporal moment of duration Tc, in the third test station 10c the second contacting assembly 13b is made available. In the time Ta1 of 0.5 seconds the second contacting assembly 13b is placed in the contacting condition in the contacting area of the third test station 10c. Immediately thereafter, the power device 18 is activated on the second contacting assembly 13c and the third test station 10c is therefore in the test condition and remains in that condition for the remaining duration (2.5 seconds) of the fourth temporal moment. At the same fourth temporal moment of duration Tc, the fourth test station 10d is in the test condition engaging the first contacting assembly 13a. The fourth test station 10d remains in the test condition for 2.5 seconds. After this time, the power device 18 interrupts the delivery of voltage to the electrochemical cell assembly present in the fourth test station 10d. The first contacting assembly 13a is de-contacted from the fourth test station 10d in a time Ta2 of 0.5 seconds. The fourth test station 10d is therefore in the waiting condition. The first contacting assembly 13a is made available.

[0193] Therefore, at each cycle time Tc (in the example of three seconds) an electrochemical cell assembly tested by the apparatus is removed and an electrochemical cell assembly to be tested is inserted into the apparatus.

[0194] In the second embodiment illustrated in Figures 10 to 12, the number N of test stations is equal to: N = ( Tb1 + Tb2 + Ttest + Ta1 + Ta2 ) I Tc, where N is an integer that approximates the result of the formula by excess. Both the insertion time Tb1 and the removal time Tb2 must be less than the cycle time Tc.

[0195] In this embodiment, the number G of contacting assemblies is equal to the number of test stations. Each contacting assembly 13 is subservient to a corresponding test station 10.

[0196] In the example illustrated in Figure 10 to 12, the design parameters of the apparatus 1 envisage that Ta1 = 0.5 seconds, Ta2 = 0.5 seconds, Tb1 = 1 second, Tb2 = 1 second and Ttest = 6 seconds. The cycle time Tc was set to 3 seconds so as to have an electrochemical cell assembly tested and removed from the apparatus every 3 seconds. By applying the above formula, the number of test stations 10 is equal to three and the number of contacting assemblies 13 is equal to three.

[0197] Figure 10 illustrates a first temporal moment of the duration Tc (3 seconds in the specific example) in which a first test station 10a is in the waiting condition and in which an electrochemical cell assembly is inserted into the press 11 of the first test station 10a according to the manners described above. The electrochemical cell assembly is inserted into the press 11 of the first test station 10a engaging the movement system 12 for a time Tb1 of 1 second. During this time the movement system 12 is not available for the removal of electrochemical cell assemblies. After insertion of the electrochemical cell assembly into the first test station 10a, a first contacting assembly 13a of the three contacting assemblies 13 is activated in the first test station 10a. In the time Ta1 of 0.5 seconds the first contacting assembly 13a is placed in the contacting condition in the contacting area of the first test station 10a. Immediately thereafter, the power device 18 is activated on the first contacting assembly 13a which is placed in the contacting condition. The first test station 10a is therefore in the test condition and remains in that condition for the remaining duration (1.5 seconds) of the first temporal moment. At the same first temporal moment of duration Tc, a second test station 10b is in the test condition engaged by a second contacting assembly 13b. The second test station 10b remains in the test condition for the duration of the first temporal moment. At the same first temporal moment of duration Tc, a third test station 10c is in the test condition engaging a third contacting assembly 13c. The third test station 10c remains in the test condition for 1 .5 seconds. After this time, the power device 18 interrupts the delivery of voltage to the electrochemical cell assembly present in the third test station 10c. The third contacting assembly 13c is de-contacted from the third test station 10c in a time Ta2 of 0.5 seconds. Immediately thereafter, the movement system 12 removes the electrochemical cell assembly from the third station 10c which therefore remains empty (i.e. without any electrochemical cell assembly inserted therein).

[0198] Figure 11 illustrates a second temporal moment of the duration Tc (3 seconds in the specific example) in which the first test station 10a is in the test condition engaged by the first contacting assembly 13a. The first test station 10a remains in the test condition for the duration of the second temporal moment. At the same second temporal moment of duration Tc, the second test station 10b is in the test condition engaging the second contacting assembly 13b. The second test station 10b remains in the test condition for 1 .5 seconds. After this time, the power device 18 interrupts the delivery of voltage to the electrochemical cell assembly present in the second test station 10b. The second contacting assembly 13b is decontacted from the second test station 10b in a time Ta2 of 0.5 seconds. Immediately thereafter, the movement system 12 removes the electrochemical cell assembly from the second test station 10b which therefore remains empty (i.e. without any electrochemical cell assembly inserted therein). At the same second temporal moment of duration Tc, the third test station 10c is in the waiting condition and an electrochemical cell assembly is inserted into the press 11 of the third test station 10c. The electrochemical cell assembly is inserted into the press 11 of the third test station 10c engaging the movement system 12 for a time Tb1 of 1 second. During this time the movement system 12 is not available for the removal of electrochemical cell assemblies. After insertion of the electrochemical cell assembly into the third test station 10c, the third contacting assembly 13c is activated in the third test station 10c. In the time Ta1 of 0.5 seconds the third contacting assembly 13c is placed in the contacting condition in the contacting area of the third test station 10c. Immediately thereafter, the power device 18 is activated on the third contacting assembly 13c which is placed in the contacting condition. The third test station 10c is therefore in the test condition and remains in that condition for the remaining duration (1.5 seconds) of the second temporal moment.

[0199] Figure 12 illustrates a third temporal moment of the duration Tc (3 seconds in the specific example) in which the first test station 10a is in the test condition engaging the first contacting assembly 13a. The first test station 10a remains in the test condition for 1 .5 seconds. After this time, the power device 18 interrupts the delivery of voltage to the electrochemical cell assembly present in the first test station 10a. The first contacting assembly 13a is de-contacted from the first test station 10a in a time Ta2 of 0.5 seconds. Immediately thereafter, the movement system 12 removes the electrochemical cell assembly from the first test station 10a which therefore remains empty (i.e. without any electrochemical cell assembly inserted therein). At the same third temporal moment of duration Tc, the second test station 10b is in the waiting condition and an electrochemical cell assembly is inserted into the press 11 of the second test station 10b. The electrochemical cell assembly is inserted into the press 11 of the second test station 10b engaging the movement system 12 for a time Tb1 of 1 second. During this time the movement system 12 is not available for the removal of electrochemical cell assemblies. After insertion of the electrochemical cell assembly into the second test station 10b, the second contacting assembly 13b is activated in the second test station 10b. In the time Ta1 of 0.5 seconds the second contacting assembly 13b is placed in the contacting condition in the contacting area of the second test station 10b. Immediately thereafter, the power device 18 is activated on the second contacting assembly 13b which is placed in the contacting condition. The second test station 10b is therefore in the test condition and remains in that condition for the remaining duration (1.5 seconds) of the second temporal moment. At the same third temporal moment of duration Tc, the third test station 10c is in the test condition engaged by a third contacting assembly 13c. The third test station 10c remains in the test condition for the duration of the third temporal moment.

[0200] Therefore, at each cycle time Tc (in the example of three seconds) an electrochemical cell assembly tested by the apparatus is removed and an electrochemical cell assembly to be tested is inserted into the apparatus.

Claims

CLAIMS1 . Hipot test apparatus (1 ) for electrochemical cell assemblies comprising: a power device (18) switchable between a test condition in which it is configured to deliver controlled voltages following a predetermined delivery law and an idle condition in which it delivers no currents; a plurality of test stations (10), wherein each test station (10) comprises a press (11 ) switchable between a test condition in which it exerts a compressive force on an electrochemical cell assembly (100) and an idle condition in which it exerts no compressive forces, each test station (10) further comprising a contacting area located at a corresponding press (11 ); at least one contacting assembly (13) switchable between a contacting condition in which it is placed in said contacting area for making electrical contact with an electrochemical cell assembly (100) and an idle condition in which it is distanced from said contacting area; a movement system (12) configured to insert an electrochemical cell assembly (100) into a press (11 ) of a related test station (10) in a time Tb1 and to remove an electrochemical cell (100) from a press (11 ) of a related test station (10) in a time Tb2; wherein: said at least one contacting assembly (13) is placed in electrical connection with said power device (18) at least when the power device (18) is in the test condition and is configured to remain continuously in the contacting condition, with the power device (18) in the test condition, for a time Ttest; said at least one contacting assembly (13) is configured to switch from the idle condition to the contacting condition in a time Ta1 and is configured to switch from the contacting condition to the idle condition in a time Ta2; each test station (10) is switchable to a test condition wherein said press (11 ) is in the test condition, wherein said contacting assembly (13) is placed in the contacting condition and wherein said power device (18) is in the test condition; each test station (10) is switchable into a waiting condition wherein said contacting assembly (13) is in the idle condition; at the same time, at least one test station (10) is in the test condition and at least one further test station (10) is in the waiting condition; a cycle time Tc representative of the time elapsing between two successive activations of the movement system (12) to remove an electrochemical cell assembly (100) from a respective test station (10) and a subsequent electrochemical cell assembly (100) from a respective test station (10) is lessthan Ta1 + Ta2 + Tb1 + Tb2 + Ttest.

2. Apparatus (1 ) according to claim 1 , wherein the movement system (12) is configured to insert or remove an electrochemical cell assembly (100) in a press (11 ) of a corresponding test station (10) only when the corresponding test station (10) is in the waiting condition.

3. Apparatus (1 ) according to any one of the preceding claims, wherein: said plurality of test stations (10) comprises a number N test stations (10), where N is an integer greater than or equal to two; wherein said at least one contacting assembly (13) comprises a number G contacting assemblies (13), where G is an integer less than or equal to N.

4. Apparatus (1 ) according to claim 3, wherein said number G of contacting assemblies (13) is equal to the number N of test stations (10) decreased by two and wherein the number N of test stations (10) is greater than or equal to three.

5. Apparatus (1 ) according to claim 4, wherein the number N of test stations (10) is provided by the integer that approximates the result by excess from the formula:N = ( 2*Tc + Ttest + Ta1 + Ta2 ) I Tc; wherein Tb1 and Tb2 are less than or equal to Tc.

6. Apparatus (1 ) according to claim 4 or 5, wherein simultaneously at least one test station (10) is in the test condition and at least two further test stations (10) are in the waiting condition.

7. Apparatus (1 ) according to claim 3, wherein said number G of contacting assemblies (13) is equal to the number N of test stations (10).

8. Apparatus (1 ) according to claim 7, wherein the number N of test stations (10) is provided by the integer that approximates the result by excess from the formula:N = ( Tb1 + Tb2 + Ttest + Ta1 + Ta2 ) I Tc; wherein Tb1 and Tb2 must be less than Tc.

9. Method for performing Hipot tests on electrochemical cell assemblies comprising:providing a plurality of test stations (10) each comprising a press (11 ); inserting an electrochemical cell assembly (100) into a press (11 ) of a test station (10); switching said press (11 ) to a test condition in which it exerts a compressive force on said electrochemical cell assembly (100); contacting said electrochemical cell assembly (100) with a contacting assembly (13); delivering controlled voltages following a predetermined delivery law to said electrochemical cell assembly (100) through said contacting assembly (13); removing an electrochemical cell assembly (100), to which controlled voltages have already been delivered, from a press (11 ) of a further test station (10) while controlled voltages are being delivered to said electrochemical cell assembly (100) through said contacting assembly (13); wherein said method comprises performing a first removal of an electrochemical cell assembly (100) from a press (11 ) of a test station (10) to which controlled voltages have already been delivered and performing a second removal of an electrochemical cell assembly (100) from a press (11 ) of a further test station (10) to which controlled voltages have already been delivered, wherein a time Tc elapsing between said first removal and said second removal is less than: Ta1 + Ta2 + Tb1 + Tb2 + Ttest, where:Ta1 represents a time for making electrical contact between a contacting assembly (13) and an electrochemical cell assembly (100);Ta2 represents a time for removing a contacting assembly (13) from an electrochemical cell assembly (100);Ttest represents a time for delivering controlled voltages following a predetermined delivery law to said electrochemical cell assembly (100);Tb1 represents a time for inserting an electrochemical cell assembly (100) into a press (11 ) of a test station (10); andTb2 represents a time for removing an electrochemical cell assembly (100) in a press (11 ) of a test station (10).

10. Method according to claim 9 wherein removing an electrochemical cell assembly (100) from a press (11 ) is performed while said press (11 ) exerts no compressive forces on said electrochemical cell assembly (100).

11. Method according to claim 9 or 10, wherein it is envisaged to provide G contacting assemblies (13) and N test stations (10) wherein N is an integer greater than or equal to two and wherein G is an integer less than or equal to N;the method comprising contacting with at least G contacting assemblies N-2 electrochemical cell assemblies (100) when N is greater than or equal to 3.

12. Method according to any one of claims 9 to 11 , wherein inserting an electrochemical cell assembly (100) into a press (11 ) of a test station (10) is performed before or after removing an electrochemical cell assembly (100) from a press (11 ) of a further test station (10).

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