DEVICE FOR CONTROLLING THE CONFORMITY OF A BATTERY BLOCK COMPONENT

Abstract

The invention relates to a device for verifying the conformity of a battery pack element (20) consisting of battery modules (22) and an underbody panel (21), before the battery pack element (20) is closed by assembly under the floor (10) of a vehicle body. The invention consists in that the verification device comprises a panel designed to form a cover for the battery pack element (20), the shape and dimensions of which reproduce the shape and dimensions of the underside of the floor (10). The device is made of an electrically insulating synthetic material and has electrically independent metal parts that, when the device is in the closed position on the battery pack element (20), allow for an insulation measurement of the battery pack thus formed, for each of these metal parts. Figure 1.

Description

Title of the invention: DEVICE FOR CHECKING THE CONFORMITY OF A BATTERY PACK ELEMENT

[0001] The present invention relates to the field of electrically powered vehicles, the vehicle body structure of which defines a passenger compartment comprising a floor under which is housed a battery powering the electric drive machine.

[0002] Battery means one or more battery modules which respectively contain at least one electrochemical cell in which current is generated by chemical reaction, for example of the lithium-ion (or Li-ion) type, of the Ni-MH, or Ni-Cd or lead type or even fuel cells.

[0003] This battery further comprises electrical or electronic means for managing the electrical energy of the module(s) which are generally grouped in a closed container or casing, thus forming a battery block, also referred to as a battery pack. The casing of the battery block forms a sealed space around the battery modules, housed between a base and a cover. This casing also contains a mounting interface and connection terminals. Such a battery block can be fixed under the floor of the body of a vehicle.

[0004] Document JP11180164 describes an electrically powered vehicle of this type in which battery modules are housed under the floor of the vehicle's body-in-white. A battery pack is thus made up of an underbody panel which has a peripheral rim thus forming a tray in which the battery modules are mounted, the assembly being fixed under the floor of the vehicle. The floor thus forms the cover of the battery pack, the battery modules being housed between the floor and the underbody panel. This assembly makes it possible to reduce the weight, the cover of the battery pack being thus replaced by the floor.

[0005] When assembling this type of battery pack, the closing of the battery pack therefore corresponds to the assembly between the element of the battery pack consisting of the battery modules and the underbody panel and the floor of the white body of the vehicle forming a cover, the assembly being carried out in the factory on the vehicle assembly lines.

[0006] Conventionally, a floor often has longitudinal and / or transverse crossmembers welded to the underside of said floor which must then be inserted between the battery modules. Thus, when assembling the battery pack element (underbody panel / battery modules), the modules are housed between the crossmembers. In the event of incorrect positioning of one of the crossmembers or battery modules at said battery pack element, a mechanical blockage may occur. causing damage, for example by crushing, to a battery module or damage to the busbars, which could then create an insulation fault or even a short circuit.

[0007] Indeed, the insulation fault can cause the body, the support swings of said body and therefore the entire assembly line to end up at the high voltage (HV) potential of the battery modules.

[0008] Furthermore, if a short circuit is created, there are risks of explosions, projection of molten metal, or even a battery fire due to heating of the cells.

[0009] Therefore, if a short circuit occurs during assembly and a battery fire occurs, it is not possible to interrupt the assembly line or evacuate the battery, which can have catastrophic consequences for the assembly line or even for the assembly plant itself.

[0010] The invention therefore aims to overcome these drawbacks by proposing a device which makes it possible to eliminate these risks during the assembly of the battery pack element on the vehicle body, in a simple and reliable manner to implement, in order to guarantee the safety of the assembly lines.

[0011] To this end, the invention proposes a device for checking the conformity of a battery pack element consisting of battery modules and an underbody panel before closing said battery pack element by assembly under the floor of a vehicle body, characterized in that said checking device consists of a panel intended to form a cover for the battery pack element, the shape and dimensions of which reproduce the shape and dimensions of the underside of the floor, said device being made of an electrically insulating synthetic material and having electrically independent metal parts allowing, when the device is in the closed position on the battery pack element, a measurement of the insulation of the battery pack thus formed, for each of these metal parts.

[0012] A device according to the invention therefore constitutes a “false” cover or temporary cover which reproduces the lower face of the floor under which the battery pack element must be fixed and makes it possible, by placing the cover on said battery pack element, to mechanically check the geometric conformity of the arrangement of the battery modules and other components of the battery pack, relative to the lower face of the floor during assembly between the two.

[0013] It is thus possible to mechanically detect whether there are physical contacts between this cover and the components of said battery block element preventing assembly, linked to poor positioning of said component elements or even to objects, for example tools, which may have been accidentally left in the said battery pack element during its manufacture.

[0014] In addition, if the device could be assembled on the battery pack element for closure, it then allows a verification of the electrical insulation of the battery pack, using the metal parts which are positioned on said cover at the level of determined risk zones of this battery pack such as zones close to the busbars. Indeed, these zones can be damaged during assembly and therefore create a break in the electrical insulation of said battery pack or may even have a defect. Thus, once the cover is assembled on the battery pack element, it is possible to carry out an insulation measurement for each of the metal parts with respect to the high voltage of the battery modules and if a contact exists between a component of the battery pack and the metal part, it is then detectable revealing a defect in the insulation of the battery pack.

[0015] The device according to the invention therefore allows, in a first step, mechanical detection of conformity during its assembly on the battery pack element and, in a second step, once the device is in place on said battery pack element, electrical detection, making it possible to check the conformity of this battery pack element before it enters the assembly line. The device according to the invention thus makes it possible to remove from this assembly line a battery pack element deemed non-compliant, thus guaranteeing the safety of said line.

[0016] The invention also relates to a method for checking the conformity of a battery pack element before its assembly under the floor of a vehicle body.Thus, in an area of ​​a battery manufacturing workshop for example, a battery element to be assembled under the floor of a vehicle body in white is checked according to the following steps: the device according to the invention is positioned on said battery element to close the battery pack, if a blockage occurs during this positioning, the battery element is deemed mechanically non-compliant and removed for rework, if the device closes the battery pack element without mechanical blocking, the battery pack element is deemed mechanically compliant and an insulation measurement is then carried out at each metal part of the device, if an insulation defect is detected, the device is deemed electrically non-compliant and removed from the assembly line, if no insulation defect is detected, the battery pack element is deemed compliant for sending to an assembly line.

[0017] Thus, if the device according to the invention cannot close the battery pack, it is removed from the assembly line and returned for rework and even if it closes the battery pack but an insulation fault is detected, it is removed from production and returned for rework.

[0018] Advantageously, the device is therefore in the form of a panel forming a cover, one face of which reproduces the surface of the lower face of the floor under which the battery pack element to be checked must be assembled. This face reproduces the reliefs of the lower face of the floor, reliefs intended for some to be inserted between the battery modules during assembly.

[0019] These reliefs such as those formed by the longitudinal and / or transverse crosspieces extend under the floor and can thus delimit housings for the battery modules, the crosspieces being inserted between said battery modules during assembly.

[0020] This panel or cover thus has on one face projecting ribs of shapes and dimensions similar to those of the crosspieces present under the floor, intended to be inserted between the battery modules of a battery pack. Preferably, this cover has dimensions corresponding to the nominal dimensions of the floor increased by a tolerance value, for example 5 mm, making it possible to absorb deviations (plays) linked to manufacturing.

[0021] Preferably, these ribs can carry metal parts making it possible to implement a measurement of the insulation fault using sensors.

[0022] Advantageously, this cover-forming device can also be used as a temporary cover forming a logistical protection for the battery pack element allowing the protection of people and said battery pack element itself from the risks caused by water, dust, rodents, falling objects between the battery production plant and the vehicle assembly plant.

[0023] The invention will be well understood and other aspects and advantages will appear clearly on reading the following description, given by way of example with reference to the attached drawing sheet in which the figures represent:

[0024] [Fig. 1] A side perspective view of a battery pack element and the bottom of the body in white before assembly;

[0025] [Fig.2] a longitudinal sectional view of a device according to the invention;

[0026] [Fig.3] a side perspective view from above of the device according to [Fig.2];

[0027] [Fig.4] a side perspective view of a battery pack element and the device according to the invention during a mechanical blockage;

[0028] [Fig.5 a side perspective view of a battery pack element and the device according to the invention during electrical detection;

[0029] [Fig.6] a schematic sectional view of a floor / battery pack assembly and device; and

[0030] [Fig.7] a block diagram of the control method according to the invention.

[0031] As can be seen in [Fig.l], the lower part 1 of the white body of a electrically powered vehicle comprises a floor 10 extending between longitudinal side members 11. Transverse cross members 12 are welded to the lower face of said floor 10.

[0032] In the case of an electrically powered vehicle, a battery pack is housed under this floor 10. This battery pack is made up of an underbody panel 21 on which are mounted battery modules 22, and other components such as electronic battery boxes 23 and busbars 24. The panel 21 has a peripheral rim forming a tray which is then fixed to the lower face of the floor 10 which thus acts as a cover for the battery pack thus made up.

[0033] The battery modules 22 and other components are positioned on the panel 21 and form a battery pack element 20 which is then assembled under the floor 10 to form the battery pack 2. During this assembly the crosspieces 12 are inserted between the modules 22 on the floor 10. These crosspieces 12 are thus also located near the bus bars 24.

[0034] In the event of incorrect positioning of one of the crosspieces 12 or the battery modules 22 or other components at the battery pack element 20, a mechanical blockage may occur between said battery pack element 20 and the floor 10, creating a risk of contact between a component of the battery pack such as a module 22, a bus bar 24 and the floor 10. There may then be a risk of degradation of a component of the battery pack by friction, or even crushing at the level of a battery module 22 or damage to the bus bars 24, which could then create an insulation fault in the battery pack, or even a short circuit.

[0035] In order to avoid such risks, the invention proposes a device 3 for checking the conformity of the battery block element 20 both from a mechanical and electrical point of view before its assembly under the floor 10 of a vehicle body in an assembly line.

[0036] This device 3 consists of a panel 31 forming a “false” cover for the battery pack element 20 and reproducing the surface of the lower face of the floor 10 of the vehicle body. This cover 3 is made of an electrically insulating synthetic material chosen from the following materials such as for example: resin, polypropylene, fiber-filled polypropylene, polyamide, polyethylene, etc., and has metal parts 32 attached in the manner of patches and distributed thereon at areas identified as critical contact areas, so that an insulation measurement is possible for each of said parts 32.

[0037] This cover 3 therefore has a shape identical to the shape of the lower face of the floor 10 reproducing the reliefs in particular induced by the crosspieces 12 or others and it has dimensions identical to the nominal dimensions of said surface incremented by a clearance value, for example 5 mm. In this way the cover 3 has dimensions corresponding to those of the floor 10 with a tolerance at allowing the absorption of the play linked to manufacturing. Thus, we can see in [Fig.6], represented schematically, a superposition of the floor 10 on the cover 3, with a play J, itself superimposed on the battery modules 22 of a battery block element 20 in a case where no mechanical or electrical contact occurs.

[0038] When the cover 3 is placed on the battery pack element 20, if the latter cannot be closed by the cover 3, it is because there is a mechanical contact blocking this closure. The battery pack element 20 is then identified as non-compliant and does not enter the assembly line.

[0039] If no mechanical blockage has occurred to prevent the removal of the cover 3 on the battery element 20, insulation measurements are then carried out on each metal part 32 using sensors 4 and if there is contact between a part or an internal component of the battery pack and this metal part 32, the sensor 4 will detect an insulation defect. The battery pack element 20 detected as non-compliant is then removed from the assembly line and returned for rework.

[0040] Thus the shape of the cover 3 makes it possible to mechanically detect the contacts which could occur during the assembly between a battery block element 20 and a floor 10 (see [Fig.4]) while the metal parts 32 make it possible to electrically detect these contacts using the sensors 4.

[0041] Thus, as can be seen in [Fig.5], these sensors 4 make it possible to detect a short circuit on the battery block element 20, for example here on the parts 32a and 32b.

[0042] This control of the conformity of said battery pack element 20 is carried out before its entry into the assembly line and allows the detection of a non-conforming battery pack element 20 which risks, during assembly on a floor 10, forming a battery pack having an insulation defect which could lead to a short circuit and cause a danger on the assembly line.

[0043] As can be seen in [Fig.7], in an area of ​​a battery workshop, the conformity of a battery element 20 consisting of an underbody panel 21 on which battery modules 22 are mounted is checked and which must be assembled under the floor 10 of a vehicle body in white.

[0044] The method comprises the following steps: Step A: the device according to the invention in the form of a cover 3 is positioned on said battery element 20, to close the battery pack 2, if a blockage occurs during this positioning, the battery element 20 is deemed N non-compliant, from a mechanical point of view and it is removed from production and returned to a retouching step E, if the device closes the battery pack element 20 without mechanical blocking, it is deemed mechanically OK, the control process is then continued, Step B: the insulation measurement is carried out at the level of each metal part 32 of the device 3 in place on the battery pack element 20, if no insulation fault is detected, the battery pack element 20 is deemed OK and sent to assembly step C; if an insulation fault is detected N, the device is deemed non-compliant from an electrical point of view and it is discarded from production and returned for a rework step E.

[0045] Thus, if the device according to the invention cannot close the battery pack, it is discarded from production and returned for rework and if it is deemed compliant from a mechanical point of view, but an insulation fault is detected, it is discarded from production and returned for rework.

[0046] The control device according to the invention makes it possible to advantageously guarantee the safety of the assembly line.

Claims

Claims

1. Device (3) for checking the conformity of a battery pack element (20) consisting of battery modules (22) and an underbody panel (21), before closing said battery pack element (20) by assembly under the floor (10) of a vehicle body, characterized in that said checking device (3) consists of a panel intended to form a cover for the battery pack element (20), the shape and dimensions of which reproduce the shape and dimensions of the underside of the floor (10), said device (3) being made of an electrically insulating synthetic material and having electrically independent metal parts (32) allowing, when the device (3) is in the closed position on the battery pack element (20), a measurement of the insulation of the battery pack thus formed for each of these metal parts (32).

2. Device according to claim 1, characterized in that it is in the form of a panel, one face of which reproduces the reliefs of the lower face of the floor (10), reliefs intended for some to be inserted between the battery modules (22) during assembly.

3. Device according to claim 2, characterized in that it has on one face projecting ribs (31) of shapes and dimensions similar to those of crosspieces (12) present under the floor (10), intended to be inserted between the battery modules (22) of a battery block element (20).

4. Device according to one of claims 1 to 3, characterized in that it has dimensions corresponding to the nominal dimensions of the floor (10), incremented by a tolerance value.

5. Device according to one of claims 1 to 4, characterized in that it is made of an electrically insulating synthetic material chosen from the following materials such as: resin, polypropylene, polypropylene loaded with fibers, polyamide, polyethylene.

6. Device according to one of claims 1 to 5, characterized in that it has metal parts (32) attached in the manner of patches and distributed thereon at the level of zones identified as critical contact zones, so that an insulation measurement is possible for each of said parts (32).

7. Device according to one of claims 3 to 6, characterized in that the ribs (31) carry metal parts (32).

8. Method for checking the conformity of a battery pack element (20) consisting of battery modules (22) and an underbody panel (21), before closing said battery pack element (20) by assembly under the floor (10) of a vehicle body, comprising the following steps: positioning (A) on said battery pack element (20) the control device according to one of claims 1 to 7, to close the battery pack, if a blockage occurs during this positioning, the battery element is judged to be non-compliant from a mechanical point of view and removed for retouching, if the device closes the battery pack element (20) without mechanical blockage, the battery pack element is judged to be compliant from a mechanical point of view;and an insulation measurement (B) is then carried out at each metal part (32) of the device, if an insulation fault is detected, the device is deemed to be non-compliant from an electrical point of view and removed from the assembly line (E), if no insulation fault is detected, the battery pack element is deemed to be compliant for sending to an assembly line.;

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