Battery assembly

Abstract

The invention relates to a battery assembly comprising at least one battery module (1). According to the invention, the battery module (1) comprises an alignment of a plurality of battery cells (2), each battery cell (2) is placed in an individual battery cell (2) chamber (3) and separated from each other by a separation plate (4), each individual battery cell chamber (3) comprises a vent (30) communicating with a discharge channel (5) for discharging the gases generated by thermal runaway arranged in an upper portion (6; 6') of the battery module (1), the discharge channel (5) is common for the plurality of battery cells (2) and comprises a lower wall (50) made up of a plate configured to form a thermal shield (51), an upper wall (52) made up of a plate configured to form a thermal shield (53) and two side edges (54) comprising a polymer-based material (56), and the battery module (1) comprises a compression system (7) provided with at least one gas outlet (8) in fluid connection with the gas discharge channel (5).

Description

Drum set

[0001] The invention relates to a battery assembly configured to manage the escape of gases generated by thermal runaway within a battery cell of the battery assembly. More particularly, the invention relates to a battery assembly comprising at least one battery module, said battery module comprising an alignment of a plurality of battery cells and being provided with a channel for evacuating gases generated by thermal runaway within a battery cell of the battery assembly.

[0002] Thermal runaway in a battery pack occurs when the temperature of one or more battery cells increases to such an extent that it initiates chain reactions that accelerate chemical reactions within the battery cell or cells, further contributing to the rapid release of thermal energy. Thermal runaway may be triggered by insufficient cooling of the battery cell or cells during operation of the battery pack. Thermal runaway may also be triggered by other events such as, for example, a short circuit, mechanical shock, exposure to extreme temperature, or a manufacturing defect. During thermal runaway, hot gases and other flammable materials may escape from the battery cell or cells.If not properly managed, the gases generated can cause a fire or explosion. For example, thermal runaway in one or more high-capacity battery cells, particularly those with NMC (Nickel, Manganese, Cobalt) technology, can lead to the release of gases with a temperature exceeding 900°C within the battery pack.

[0003] Already known in the prior art, in particular from document US 2019 / 0173068 A1, but also from documents EP 2 637 235 A1, US 2015 / 214525 A1 and EP 2 538 470 A1, is a battery assembly comprising a battery module comprising an alignment of a plurality of battery cells, said battery module being provided with a gas evacuation channel. In the disclosed module, the evacuation channel is in fluid connection with the plurality of battery cells by means of a slot extending along the evacuation channel, this slot being common to the plurality of battery cells. Such an arrangement makes it possible to ensure evacuation of gases generated by thermal runaway within a battery cell. However, such a device for evacuating gases generated by thermal runaway within a battery cell does not significantly reduce the risk of thermal runaway in other battery cells.

[0004] The invention aims in particular to provide a battery assembly making it possible to minimize the propagation of thermal runaway from one battery cell to the other battery cells.

[0005] To this end, the invention relates to a battery assembly comprising at least one battery module.According to the invention, the battery module comprises an alignment of a plurality of battery cells, each battery cell being placed in an individual battery cell chamber and separated from each other by a separation plate, each individual battery cell chamber comprising a vent communicating with a channel for discharging gases generated by thermal runaway arranged in an upper part of the battery module, said discharge channel being common for the plurality of battery cells and comprising a lower wall consisting of a plate configured to form a heat shield, an upper wall consisting of a plate configured to form a heat shield and two lateral edges comprising a polymer-based material, the battery module comprising a compression system provided with at least one gas outlet in fluid connection with the gas discharge channel.

[0006] Thus, a battery module such that each battery cell is located in an individual battery cell chamber comprising a vent communicating with a channel for discharging gases generated by thermal runaway disposed in the upper portion of the battery module makes it possible to reduce the risk of propagation of thermal runaway from one battery cell of the plurality of battery cells to the other battery cells. The presence of a vent per battery cell chamber makes it possible to reduce the risk of contact between the gases generated by thermal runaway of one battery cell and the other battery cells.In addition, the battery module is provided with a gas evacuation channel arranged in its upper part, said evacuation channel being common for the plurality of battery cells and comprising a lower wall constituted by a plate configured to form a heat shield, an upper wall constituted by a plate configured to form a heat shield and two lateral edges comprising a polymer-based material. Thus, an evacuation channel having such a structure makes it possible to have an evacuation channel configured to reduce the propagation of the heat generated within the battery assembly while having a flexibility of said channel capable of withstanding significant temperature and pressure constraints linked to the evacuation of the gases generated by thermal runaway. Preferably, the upper wall constituted by a plate configured to form a heat shield is a stainless steel or ceramic plate.The presence of a compression system equipped with at least one gas outlet in fluid connection with the gas evacuation channel makes it possible to improve the durability as well as the safety of the battery assembly due to the possible swelling of the battery cells during their lifetime. The compression applied to the battery cells by the compression system is linked to the battery cell technology but also to the format of the battery cells. Preferably, the lower wall of the evacuation channel is constituted by a metal or ceramic plate, preferably by a metal plate covered by a ceramic coating on its part exposed to the gases generated by thermal runaway.Preferably, the upper wall of the discharge channel is constituted by a metal plate covered by a ceramic coating on its part exposed to the gases generated by thermal runaway. The notions of "upper" and "lower" relating to the gas discharge channel are taken with the ground as a reference for a battery assembly in the operating position. By the expression "a polymer-based material", it is meant that the material comprises at least 50% by weight of said polymer.

[0007] According to a preferred embodiment, the battery assembly according to the invention is such that the polymer-based material comprises a polymeric foam.

[0008] Thus, the presence of a polymeric foam makes it possible, due to the height tolerance of the cells which constitute the foam, to create a given level of sealing and to limit the volume of gas which could escape from the gas evacuation channel arranged in the upper part of the battery module. The notion of "upper" relative to the battery module is taken with the ground as a reference for a battery assembly in the operating position.

[0009] According to a preferred embodiment, the battery assembly according to the invention is such that the polymer-based material constituting the two lateral edges is covered with a metallic film or a ceramic film on at least its parts exposed to the gases generated by thermal runaway.

[0010] Thus, the presence of a metallic film or a ceramic film on at least the parts of the side edges exposed to the gases generated by thermal runaway makes it possible to avoid degradation of the polymer-based material by a heat dissipation effect or by a heat shield effect.

[0011] According to a preferred embodiment, the battery assembly according to the invention is such that at least one of the two lateral edges of the channel for discharging gases generated by thermal runaway is constituted in part by a fold of the upper wall constituted by the plate configured to form a thermal shield. Preferably, the two lateral edges of the channel for discharging gases generated by thermal runaway are constituted in part by a fold of the upper wall constituted by the plate configured to form a thermal shield. More preferably, the lateral edge(s) made of a polymer-based material are inserted into a groove or an angle iron present in the upper wall constituted by the plate configured to form a thermal shield.

[0012] Thus, a fold of the upper wall constituted by the plate configured to form a heat shield constituting at least one of the two lateral edges of the channel for discharging gases generated by thermal runaway, preferably the two lateral edges of the channel for discharging gases generated by thermal runaway, makes it possible to reduce the risks of degradation of the polymer-based material. Advantageously, the plate configured to form a heat shield also incorporates a specific shape which makes it possible to protect the polymer-based material, this specific shape is constituted by a fold of the upper wall constituted by the plate configured to form a heat shield, preferably said fold is in the form of a groove or an angle iron.

[0013] According to a preferred embodiment, the battery assembly according to the invention is such that the gas evacuation channel is located in the center of the upper part of the battery module.

[0014] Thus, an evacuation channel located in the center of the upper part of the battery module makes it possible to optimize the evacuation of gases generated by thermal runaway in the battery module. The expression "in the center of the upper part of the battery module" is intended to denote the fact that the gas evacuation channel is located on a straight line cutting the upper part of the battery module into two approximately equal parts according to the direction of alignment of the plurality of battery cells.

[0015] According to a preferred embodiment, the battery assembly according to the invention is such that the compression system provided with at least one gas outlet in fluid connection with the gas evacuation channel comprises at least two compression plates located on either side of the battery module in the direction of alignment of the plurality of battery cells, at least one of the two plates, preferably both plates, comprising a gas outlet in the form of a pipe perpendicular to the direction of alignment of the plurality of battery cells, said pipe being directed towards the bottom of the battery module.

[0016] Thus, a compression system comprising a gas outlet in the form of a pipe perpendicular to the direction of alignment of the plurality of battery cells allows control of the outlet of gases generated by thermal runaway from the bottom of the battery module.

[0017] According to a preferred embodiment of the preceding embodiment, the battery assembly is such that said at least one of the two compression plates comprises a compression panel and a thermal protection panel comprising the gas outlet in the form of a conduit perpendicular to the direction of alignment of the plurality of battery cells, said thermal protection panel being based on a material selected from a ceramic material and a metallic material, preferably the thermal panel is made of steel. Preferably, the compression panel is based on Polyphthalamide (PPA).

[0018] Thus, the use of a thermal protection panel based on a material selected from a ceramic material and a metallic material makes it possible to minimize the propagation of thermal energy from the gases generated by thermal runaway within the battery assembly. The expression "a thermal protection panel being based on a material" is intended to denote the fact that the thermal protection panel is made up of at least 50% by weight of said material.

[0019] According to a preferred embodiment, the battery assembly is such that it comprises a support frame for at least one battery module, said support frame comprising a gas exhaust line in the central part and a gas exhaust zone on the outer edges of the support frame, the gas exhaust line in the central part and the gas exhaust zone on the outer edges of the support frame being in fluid connection with the gas outlet of the compression system, preferably the gas outlet of the compression system is in the form of a conduit within a compression plate of the battery module, said conduit being perpendicular to the direction of alignment of the plurality of battery cells.

[0020] Thus, a battery assembly comprising a support frame for at least one battery module, said support frame comprising a gas exhaust line in the central part and a gas exhaust zone on its outer edges, makes it possible to ensure optimum evacuation of the gases generated by thermal runaway while optimizing their cooling when said support frame is close to a cooling plate.

[0021] According to a preferred embodiment, the battery assembly according to the invention is such that the gas exhaust line in the central part and the gas exhaust zone on the outer edges of the support frame are provided with an outlet comprising a safety valve. Preferably, the safety valve is a membrane valve, preferably a membrane based on Polytetrafluoroethylene (PTFE).

[0022] Thus, the presence of a safety valve allows a controlled escape of gases generated by thermal runaway.

[0023] According to a preferred embodiment, the exhaust channel disposed in the upper portion of the battery module has several baffles configured to guide gases generated by thermal runaway.

[0024] This allows for more efficient evacuation of gases generated by thermal runaway. In addition, baffles protect the vents by preventing gases generated by thermal runaway moving in the exhaust channel from approaching them.

[0025] According to a preferred embodiment, the battery assembly comprises a cooling plate common to the entire battery module, or even common to all the battery modules. Said cooling plate is in thermal connection with the support frame, preferably is joined to the support frame, more preferably the cooling plate constitutes the support frame.

[0026] According to other optional features of the battery assembly according to the invention taken alone or in combination: The battery cells of the battery module are connected in series or in parallel. The battery module comprises a metal locking plate, preferably made of aluminum, screwed to the compression system and to the cooling plate. Such a locking plate makes it possible to increase the heat exchange surface between the battery cells and the cooling plate. The upper part of the battery module integrates: means for positioning and fixing electrical conduit or "Busbar" in English; means for positioning and fixing flexible printed circuits.

[0027] The invention also relates to a motor vehicle comprising a battery assembly according to the invention. Brief description of the figures

[0028] The invention will be better understood on reading the following description, given solely by way of example and with reference to the appended drawings in which:

[0029] is an exploded view of a battery module of a battery assembly according to the invention.

[0030] is a bottom view of the upper portion of the battery module of a battery pack shown in.

[0031] is a cross-section of the upper portion of the battery module of a battery pack shown in.

[0032] is a side view of a portion of a battery module compression system of a battery pack shown in.

[0033] is an exploded view of a portion of a battery module compression system of a battery pack shown in.

[0034] is a longitudinal section of the battery module of a battery pack shown in.

[0035] is a partial section of the top of the battery module support frame of a battery pack shown in.

[0036] is a top view of the battery module support frame of a battery pack shown in.

[0037] is a bottom view of the upper portion of the battery module of a battery assembly shown in accordance with an alternative embodiment of the invention. Detailed description

[0038] Figures 1 to 9 show a battery assembly according to an embodiment of the invention. In these figures 1 to 9, similar elements are designated by identical references.

[0039] Larepresents a battery module 1 of the battery assembly according to the invention. The battery module 1 comprises an alignment of a plurality of battery cells 2, each battery cell 2 being placed in an individual battery cell chamber 2 and separated from each other by a separation plate, each individual battery cell chamber comprising a vent 30 communicating with a gas discharge channel 5 arranged in an upper portion 6 of the battery module 1, said discharge channel 5 being common for the plurality of battery cells 2 and being located in the center 60 of the upper portion 6 of the battery module 1. The battery module 1 also comprises a compression system 7 provided with at least one gas outlet in fluid connection with the gas discharge channel 5.The battery module 1 comprises two metal locking plates 10, preferably made of aluminum, screwed to the compression system 7 and to a cooling plate. The locking plates 10 make it possible to increase the heat exchange surface between the battery cells 2 and the cooling plate.

[0040] The upper part 6 is disclosed in a view from below of the battery module shown in the figure. The upper part 6 of the battery module 1 comprises the upper wall 52 of the gas evacuation channel, said wall comprising a plate configured to form a heat shield and constituting the upper wall 52 of the gas evacuation channel. It is observed that folds of the upper wall constituted by the plate configured to form a heat shield form at least a portion of two lateral edges 54 of the channel for evacuating gases generated by thermal runaway, these folds being in the form of a groove or angle iron. The upper part 6 also comprises means for positioning and fixing electrical conduit or "Busbar" 55 as well as means for positioning and fixing flexible printed circuits (not shown).

[0041] La represents a cross-section of the upper part 6 of the battery module 1 shown in the. The upper part 6 of the battery module 1 comprises a channel 5 for discharging gases generated by thermal runaway, said channel being formed by a lower wall 50 consisting of a plate configured to form a heat shield 51, by an upper wall 52 consisting of a plate configured to form a heat shield 53 and two lateral edges 54. The lateral edges 54 of the gas discharge channel 5 being constituted on the one hand by a fold of the upper wall 52 consisting of the plate configured to form a heat shield 53 and on the other hand by a polymer-based material 56. It is observed that the lateral edges 54 are such that the polymer-based material 56 is inserted into a groove or an angle iron present in the upper wall 52 consisting of the plate configured to form a heat shield 53.

[0042] Figures 4 and 5 illustrate one of the two plates 70 of the compression system. The plate 70 comprises a compression panel 700, preferably made of polyphthalamide (PPA) and a thermal protection panel 701, preferably made of steel, provided with a gas outlet 71. The represents a view of the thermal protection panel 701 comprising a gas outlet 71.

[0043] La represents a longitudinal section along a plane A of the battery module 1 of a battery assembly shown in the. The battery module 1 comprises an alignment of a plurality of battery cells (not shown), each battery cell being placed in an individual chamber 3 of battery cell 2 and separated from each other by a separation plate 4, each individual chamber 3 of battery cell 2 comprising a vent 30 communicating with a gas discharge channel 5 arranged in an upper part 6 of the battery module 1, said discharge channel 5 being common for the plurality of battery cells. The battery module 1 comprises a compression system 7 provided with at least one gas outlet 8 in fluid connection with the gas discharge channel 5. The arrows indicate the direction of discharge of the gases generated by thermal runaway within the battery module 1.

[0044] The figure shows a partial section of the top of the support frame 9 of a battery module 1 of a battery assembly shown in the figure. The support frame 9 supports the individual battery cell chambers 3 separated from each other by separating plates 4. The metal locking plate 10 is in thermal connection with the support frame 9. The gas outlet 8 of the compression system is also shown. The arrow indicates the direction of flow of gases generated by thermal runaway.

[0045] La represents a top view of the support frame 9 of the battery module 1 of a battery assembly shown in the. The support frame 9 comprises a gas exhaust line in the central part 90 of said support frame 9, a gas exhaust zone on the outer edges 91 of the support frame 9, outlets 92 of the gas exhaust line in the central part 90 and of the gas exhaust zone on the outer edges 91 of the support frame 9. Each outlet 92 is provided with a safety valve 93. The support frame 9 comprises a cold plate 94. The arrows indicate the direction of evacuation of the gases generated by thermal runaway within the battery module.

[0046] La represents a bottom view of an upper part 6', of the battery module 1, according to an alternative embodiment of the invention. The upper part 6' of the battery module 1 differs from that presented above in that the discharge channel 5 arranged in the upper part 6' of the battery module 1 has several deflectors 57 configured to guide gases generated by thermal runaway, in order to discharge them more efficiently. Each deflector 57 is in the form of a straight rib in the general shape of a "V" so that the gas encountering one of the deflectors arrives at the apex of the "V" of this deflector and goes around it on either side of it, so that the interior of the "V" is sheltered from the gas. In other words, the deflectors form an arrow pattern whose direction is opposite to the direction of discharge of the gases in the discharge channel 5.The deflectors 57 may be arranged in the discharge channel 5 so as to be located above some of the vents 30, or even all of the vents 30, so that they open into the discharge channel 5 inside the “V” of one of the deflectors 57. In this way, the vents 30 are sheltered from gases that may come from the thermal runaway of another battery cell 2, which makes it possible to prevent these gases from damaging the vents 30. List of references

[0047] 1: battery module2: battery cell(s)3: individual battery cell chamber4: separation plate5: gas evacuation channel6; 6': upper part of the battery module7: compression system8: gas outlet of the compression system9: support frame10: metal locking plate30: vent of an individual battery cell chamber50: lower wall of the gas evacuation channel51: plate configured to form a heat shield constituting the lower wall of the gas evacuation channel52: upper wall of the gas evacuation channel53: plate configured to form a heat shield constituting the upper wall of the gas evacuation channel54: two lateral edges of the gas evacuation channel55: means for positioning and fixing electrical conduit or "Busbar"56: polymer-based material

[0048] 57: deflector60: center of the upper part of the module70: compression plates of the compression system71: gas outlet of a compression plate90: gas exhaust line in the central part of the support frame91: gas exhaust area on the outer edges of the support frame92: outlet of the gas exhaust line in the central part and of the gas exhaust area on the outer edges of the support frame93: safety valve94: cold plate700: compression panel701: thermal protection panel

Claims

Battery assembly comprising at least one battery module (1), said battery module (1) comprising an alignment of a plurality of battery cells (2), each battery cell (2) being placed in an individual battery cell (2) chamber (3) and separated from each other by a separation plate (4), each individual battery cell chamber (3) comprising a vent (30) communicating with an evacuation channel (5) for gases generated by thermal runaway arranged in an upper part (6;6') of the battery module (1), said discharge channel (5) being common for the plurality of battery cells (2) and comprising a lower wall (50) constituted by a plate configured to form a heat shield (51), an upper wall (52) constituted by a plate configured to form a heat shield (53) and two lateral edges (54) comprising a material based on a polymer (56), the battery module (1) comprising a compression system (7) provided with at least one gas outlet (8) in fluid connection with the gas discharge channel (5).; Battery assembly according to claim 1, such that the polymer-based material (56) constituting the two lateral edges (54) is covered with a metallic film or a ceramic film on at least its parts exposed to gases generated by thermal runaway. Battery assembly according to any one of the preceding claims, such that at least one of the two lateral edges (54) of the evacuation channel (5) for the gases generated by thermal runaway is constituted in part by a fold of the upper wall (52) constituted by the plate configured to form a thermal shield (53). Battery assembly according to any one of the preceding claims, such that the gas discharge channel (5) is located in the center (60) of the upper part (6; 6') of the battery module (1). Battery assembly according to any one of the preceding claims, such that the compression system (7) provided with at least one gas outlet (8) in fluid connection with the gas evacuation channel comprises at least two compression plates (70) located on either side of the battery module (1) in the direction of alignment of the plurality of battery cells (2), at least one of the two plates (70) comprising a gas outlet (71) in the form of a conduit perpendicular to the direction of alignment of the plurality of battery cells (2), said conduit being directed towards the bottom of the battery module (1). Battery assembly according to the preceding claim, such that said at least one of the two compression plates (70) comprises a compression panel (700) and a thermal protection panel (701) comprising the gas outlet (71) in the form of a conduit perpendicular to the direction of alignment of the plurality of battery cells (2), said thermal protection panel (701) being based on a material selected from a ceramic material and a metallic material. Battery assembly according to any one of the preceding claims, such as it comprises a support frame (9) for at least one battery module (1), said support frame (9) comprising a gas exhaust line in the central part (90) and a gas exhaust zone on the outer edges (91) of the support frame (9), the gas exhaust line in the central part (90) and the gas exhaust zone on the outer edges (91) of the support frame (9) being in fluid connection with the gas outlet (8) of the compression system (7). Battery assembly according to the preceding claim, such that the gas exhaust line in the central part (90) and the gas exhaust zone on the outer edges (91) of the support frame (9) are provided with an outlet (92) comprising a safety valve (93). Battery assembly according to the preceding claim, such that the safety valve (93) is a diaphragm valve. Battery assembly according to any one of the preceding claims, such that the exhaust channel (5) arranged in the upper part (6') of the battery module (1) has several deflectors (57) configured to guide gases generated by thermal runaway. Motor vehicle comprising a battery assembly according to any one of the preceding claims.

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