Battery unit for an electric vehicle

Abstract

The present disclosure relates to a battery cell group comprising: a battery cell having first and second terminals and a vent located on a bottom side of the battery cell; a frame on the bottom side of the battery cell, the frame comprising a frame plate having first and second openings aligned with the first and second terminals and a third opening aligned with the vent and first and second intermediate frame walls extending perpendicular to the frame plate; and a thermal protection plate extending between the intermediate frame walls, wherein the intermediate frame walls and the thermal protection plate form a channel between the terminals along a length of the bottom side of the battery cell. The present disclosure also relates to a battery pack comprising a plurality of battery cell groups and an electric vehicle comprising the battery pack.

Description

Technical Field

[0001] This disclosure relates to a battery cell pack for an electric vehicle, a battery pack comprising multiple battery cell packs, and an electric vehicle comprising a battery pack. Background Technology

[0002] Electric vehicles (EVs), such as battery electric vehicles (BEVs), use high-voltage batteries as their energy source. To provide sufficient driving range using current battery cell technology, the battery is located beneath the cabin. Batteries typically consist of multiple battery cells connected in series or parallel. Each battery cell has two terminals and a vent on its top side facing the EV cabin. The vent allows the release of flammable gases produced by the electrolyte within the battery cell during the battery's lifespan.

[0003] To handle thermal events such as thermal runaway, thermal protection panels are typically placed between the top cover and the top side of the battery, including terminals and battery cell vents, to protect the vehicle's passenger compartment from high temperatures.

[0004] In addition, to reduce the temperature of the battery cell, a cooling plate is typically installed below the bottom side of the battery cell, opposite to the top side. Furthermore, to reduce heat loss from the battery cell and cooling system to the environment, thermal insulation material is installed below the cooling system. Summary of the Invention

[0005] According to one aspect of this disclosure, this application provides a battery cell assembly. The battery cell assembly includes: a battery cell having a first terminal and a second terminal and a vent on the bottom side of the battery cell; a frame on the bottom side of the battery cell, the frame including a frame plate having a first opening and a second opening aligned with the first and second terminals and a third opening aligned with the vent, and first and second intermediate frame walls extending perpendicularly to the frame plate; and a thermal protection plate extending between the intermediate frame walls, wherein the intermediate frame walls and the thermal protection plate form a channel between the terminals along the length of the bottom side of the battery cell. The intermediate frame walls may extend along the thickness direction of the battery cell. Therefore, the channel may also extend along the thickness direction of the battery cell. As described in the background art, a typical configuration requires a thermal protection plate between the battery cell and the vehicle floor to protect passengers in the event of thermal runaway. Since a cooling plate is located on the top side of the battery cell, this configuration provides a protective barrier for the vehicle compartment. This specific configuration and arrangement provides this protection without increasing the battery height, thereby providing a more compact battery structure for the engine.

[0006] In the context of this disclosure, when the battery cell is in the operating position, the bottom side of the battery cell is the side facing downwards. In the operating position, the battery cell can be used in a battery cell array, such as the battery cell array of this disclosure.

[0007] In one example of this disclosure, two intermediate frame walls are respectively disposed between each opening of the terminal and the battery cell vent. This means that each of the two intermediate frame walls is arranged between one of the first and second openings for the terminal and a third opening for the vent. This arrangement of the intermediate frame walls between the first and second openings and the third opening allows for the prevention of short circuits between the battery cell terminals due to conductive exhaust gas through the battery cell vent. In other words, the intermediate frame walls form a barrier between one of the first and second openings and the third opening.

[0008] In one example of this disclosure, the frame of the battery cell assembly further includes first and second end frame walls that extend perpendicularly to the frame plate and are disposed on end sides of the bottom surface. Such end frame walls allow the first and second terminals of the battery cells to be isolated from any coolant (e.g., gas or liquid) flowing between adjacent battery cell assemblies. This reduces the risk of short circuits between the terminals of adjacent battery cell assemblies. The first and second end frame walls may extend along the thickness direction of the battery cell.

[0009] In one example of this disclosure, the frame comprises a plastic material. Examples of suitable plastic materials are polypropylene and polyethylene, as well as similar plastic materials. Such plastic materials are capable of providing good electrical and thermal insulation, allowing for electrical and thermal isolation of any components beneath the frame from terminals and emitted gases. Furthermore, plastic materials are relatively inexpensive and generally easy to manufacture, thus saving costs.

[0010] In one example of this disclosure, the thermal protection plate comprises a mica material. Such a mica material possesses excellent electrical and thermal insulation properties, allowing components beneath the thermal protection plate to be electrically and thermally isolated from emitted gases. The use of the mica material prevents thermal damage to the battery's base plate, enabling gases to be expelled from the battery in a controlled manner.

[0011] In one example of this disclosure, the battery cell is a rectangular battery cell. This means that the cross-section of the battery cell is approximately rectangular, rather than circular. For example, the battery cell can be a prismatic battery cell or a pouch battery cell. Such a shape allows for the stacking of battery cells with high packaging efficiency, thereby reducing the overall volume required for the battery cell. Preferably, the battery cell is a prismatic battery cell.

[0012] In one example of this disclosure, the battery cell assembly may also include a base plate extending parallel to the bottom side of the battery cells and contacting the first and second intermediate frame walls. Such a base plate supports the battery cell assembly. In this context, the intermediate frame walls not only form channels for venting gases but also make the battery cell assembly mechanically more reliable and stable. In short, the intermediate frame walls have a structural function.

[0013] It should be noted that in an alternative embodiment, the base plate does not contact the first and second intermediate frame walls or only contacts one of the first and second frame walls. Of course, in this structure, short circuits between battery cell terminals due to conductive exhaust gas through the battery cell vents must also be avoided. This may be possible if the first and second intermediate frame walls are of sufficient size.

[0014] In one example of the invention, the thermal protection plate is in contact with the base plate. This configuration of the thermal protection plate allows for maximizing the volume of the channels, thereby allowing the maximum amount of gas to flow out of the battery pack.

[0015] In one example of this disclosure, the base plate comprises aluminum. The use of aluminum allows for a uniform distribution of high temperatures along the base plate. This uniform distribution allows the base plate to cool down faster than when hot spots occur along the base plate.

[0016] In one example of this disclosure, the battery cell pack also includes a cooling plate disposed above the top side of the battery cell, opposite to the bottom side. Such a cooling plate stabilizes the battery cell temperature and provides optimal temperature uniformity. This allows for lowering the temperature of the battery cell pack and forming a thermal barrier to the vehicle compartment in the event of a battery cell thermal event, without requiring an additional thermal protection barrier. As described in the background section, a typical configuration requires a thermal protection plate located below the cooling plate to protect the cooling plate (above the bottom side of the battery cell) from external heat loss, thereby further increasing the battery height.

[0017] In one example of this disclosure, the cooling plate comprises aluminum. Aluminum is a lightweight material, which further reduces the weight of the battery cell assembly.

[0018] In one example of this disclosure, the battery cell assembly also includes a thermal interface material (TIM) disposed between the top side of the battery cell and a cooling plate. The TIM facilitates heat flow, allows for heat distribution along the cooling plate, and allows for reduction of uneven temperature distribution between adjacent battery cells. Figure 1 As shown, the current configuration makes the battery cell pack more compact.

[0019] In one example of this disclosure, the battery pack includes multiple battery cell groups arranged in a stacked manner, such that the first and second terminals of the multiple battery cell groups are aligned to form a first terminal block and a second terminal block on the bottom side of the battery pack; and the vents of the multiple battery cell groups are aligned to form a vent row on the bottom side of the battery pack. Conventional battery manufacturing processes proceed from battery cells to modules, and then from modules to packs. This intermediate step divides the battery into individual modules. In this design, the terminal plates, side plates, and internal connectors of the modules occupy space and weight. The battery pack provided by this disclosure reduces the height of the battery pack (on the z-axis) because there are fewer layers in the battery pack and the module structure is eliminated, thus reducing weight. In other words, the battery pack according to this disclosure is not divided into modules or does not include modules. Instead, the battery pack is directly formed by arranging multiple battery cell groups in a stacked manner.

[0020] In the context of this article, the bottom side of the battery pack is the side of the battery pack facing downwards when the battery pack is in its operational position (e.g., installed in a vehicle).

[0021] In one example of this disclosure, the electric vehicle includes a passenger compartment and a battery pack located below the passenger compartment. In other words, when the vehicle is in its operating position, i.e., in its drivable position, the battery pack is arranged vertically below the passenger compartment. The battery height directly affects the vehicle height, and thus affects vehicle power consumption. This invention reduces the height of the battery cell pack, thereby improving overall vehicle efficiency.

[0022] In one example, the first and second terminals of the plurality of battery cells in the battery pack are oriented away from the passenger compartment. This means that in the vehicle's operating position, the first and second terminals face downwards. As mentioned earlier, this orientation allows for a reduction in the height of the battery pack, especially when compared to existing battery packs.

[0023] These features and structures can be included in various combinations, such as some of these features and structures, all of these features and structures, or one of these features and structures. Attached Figure Description

[0024] The invention will now be described in more detail with reference to the preferred embodiments shown in the accompanying drawings, wherein:

[0025] Figure 1 A schematic diagram of the battery cell assembly is shown.

[0026] Figure 2 Another schematic diagram of the battery cell assembly is shown.

[0027] Figure 3 A schematic diagram of the battery pack is shown.

[0028] Figure 4The vehicle, including the battery pack, is shown. Detailed Implementation

[0029] Various aspects of this disclosure will now be described more fully below with reference to the accompanying drawings, in which certain embodiments of the disclosure are illustrated.

[0030] Figure 1 and Figure 2 A schematic diagram of a battery cell assembly 10 is shown. The battery cell assembly 10 can also be referred to as a battery cell block. Directions X, Y, and Z are shown in each diagram to help explain the relative arrangement of features of the battery cell assembly 10. The battery cell assembly 10 includes a battery cell 20 (e.g., a lithium-ion electrochemical battery), a frame 30, and a thermal protection plate 40. The battery cell 20 includes a first terminal 21a, a second terminal 21b, and a vent 22 located on the bottom side of the battery cell. The bottom side of the battery cell 20 is opposite to the top side of the battery cell. The first terminal 21a and the second terminal 21b correspond to the positive and negative terminals of the battery cell, respectively, or vice versa. Terminals 21a and 21b are both configured to be conductive and are made of a conductive material such as a metal (e.g., aluminum, copper, nickel-plated steel, or other suitable alloys).

[0031] like Figure 1 and Figure 2 As shown, the battery cell 20 has a rectangular shape and includes a top side 20b, a bottom side 20a, two lateral sides 20e, a front side 20c, and a rear side 20d. The top side 20a and the bottom side 20b are substantially parallel to each other. The two lateral sides 20e are substantially parallel to each other. The front side and the rear side 20c and 20d are substantially parallel to each other. Each pair of substantially parallel sides is perpendicular to the other pairs. Figures 1-2 The shape of the battery cell 20 in the figure is for illustration only, and therefore it is possible to have more lateral sides than shown in the figure.

[0032] A vent 22 in the battery cell allows gas formed inside the battery cell to escape from the battery cell 20. The vent 22 is located between a first terminal 21a and a second terminal 21b on the bottom surface of the battery cell 20. The battery cell serves as a power source. During use, the battery cell generates heat, which in turn generates gas inside the battery cell, increasing the internal pressure. To prevent excessive internal pressure, the vent acts as a valve, opening when the pressure exceeds a given value, thereby allowing gas to escape from the battery cell 20.

[0033] The frame 30 of the battery cell assembly 10 is located on the bottom side 20a of the battery cell 20. The frame 30 supports the battery cells disposed on the top of the frame. The frame 30 includes a frame plate 32, which includes: first and second openings 23a, 23b aligned with the first and second terminals 21a, 21b; a third opening 23c aligned with the vent 22; and first and second intermediate frame walls 34a, 34b extending perpendicularly to the frame plate 32. Optionally, the first and second intermediate frame walls 34a, 34b can be integrally formed with the frame plate 32. Alternatively, the first and second intermediate frame walls 34a, 34b can be formed separately and then attached to the frame plate 32 by, for example, adhesive, welding or any other suitable means. Optionally, the first, second and third openings can have a rectangular shape. Alternatively, the first, second and third openings can have any other shape, such as a circle, a square or any other polygon.

[0034] The intermediate frame walls 34a, 34b and the thermal protection plate 40 form a channel 80 between the terminals 21a, 21b, extending along the length of the bottom side of the battery cell 20. The channel 80 allows gas discharged through the vent 22 to flow out of the battery cell assembly 10.

[0035] In one embodiment, the first and second intermediate frame walls 34a, 34b are respectively disposed between the terminals 21a, 21b and each opening 23a, 23b, 23c of the battery cell vent 22. Optionally, the dimensions of the first and second intermediate frame walls 34a, 34b on the X-axis are such that there is space between each intermediate frame wall 34a, 34b and any of the first, second, and third openings 23a, 23b, 23c aligned with the terminals 21a, 21b and the vent 22. Such space maximizes the volume of the channel 80 (particularly on the X-axis), thereby providing more space for gas to flow out of the battery cell assembly 10.

[0036] Optionally, the frame 30 may also include first and second end frame walls 36a, 36b extending perpendicularly to the frame plate 32 and disposed on the end sides of the bottom surface. The first end frame wall 36a and the second end frame wall 36b may be integrally formed with the frame plate 32. Alternatively, the first end frame wall 36a and the second end frame wall 36b may be formed separately and then attached to the frame plate 32 by, for example, adhesive or welding. The dimensions of the first and second intermediate frame walls 34a, 34b and the first and second end frame walls 36a, 36b in the X-axis allow for an additional space between each end frame wall 34a, 34b and any of the first and second openings 23a, 23b aligned with the terminals 21a, 21b. Such a space in the X-axis allows heat to be removed from the terminals (heated during battery use) and thus from the battery cell when a fluid (e.g., a gas or dielectric liquid) passes through the terminals (heated during battery use) which are at a lower temperature than the terminals.

[0037] according to Figure 1 and Figure 2 In the exemplary embodiment shown, frame 30 comprises a plastic material. That is, the entire frame 30 or one or more of its components (frame plate 32, first and second intermediate frame walls 34a, 34b, and first and second end frame walls 36a, 36b) comprises a plastic material. Suitable plastic materials include, but are not limited to, polyamide (“PA”), polyethylene (“PE”), polyvinyl chloride (“PVC”), polypropylene (“PP”), polycarbonate (“PC”), polyoxymethylene (“POM” or acetal) and combinations thereof, and can help ensure good thermal and electrical insulation of the frame. Preferably, the plastic material is at least one of PA, PVC, and PP.

[0038] like Figure 1 and Figure 2 As shown, the battery cell assembly 10 includes a thermal protection plate 40. The thickness of the thermal protection plate 40 will vary depending on the battery cell capacity and its heat generation potential. Optionally, the thermal protection plate 40 comprises a mica material. Such a mica material can be easily cut and shaped to the desired thickness.

[0039] like Figure 1 and Figure 2 As shown in the exemplary embodiment, the battery cell 20 is a rectangular battery cell. The battery cell 20 has a thickness (measured along the Y-axis), a length (measured along the X-axis), and a height (measured along the Z-axis). An example of a rectangular battery cell is a prismatic battery cell. Compared to other shapes (e.g., cylindrical battery cells), such a rectangular shape allows for the stacking of a greater number of battery cells using minimal space. Preferably, the battery cell 20 is a prismatic battery cell.

[0040] The battery cell assembly 10 includes a base plate 50 extending parallel to the bottom side 20a of the battery cell 20 and contacting the first and second intermediate frame walls 34a, 34b. Optionally, the base plate 50 also contacts the first and second end frame walls 36a, 36b. The base plate 50 can be attached to the intermediate frame walls 34a, 34b and / or end walls 36a, 37b by gluing, fastening, welding, or any other suitable means. Such a base plate serves as a bottom cover for the battery frame, thereby sealing the battery cell relative to the outside.

[0041] According to one embodiment, the thermal protection plate 40 is in contact with the base plate 50. Optionally, the thermal protection plate 40 can be glued to the base plate 50 or welded to the base plate 50. The first and second intermediate walls 34a, 34b, the thermal protection plate 40, and the bottom side 20a of the battery cell 20 form a channel 80 through which gas can flow out of the battery cell pack.

[0042] According to the illustrated embodiment, the battery cell assembly 10 includes a cooling plate 70 disposed above the top side 20b of the battery cell 20, opposite to the bottom side 21a. This cooling plate dissipates heat generated from the battery cell. The cooling plate 70 can be made of metal. Suitable metals include, but are not limited to, aluminum, steel, stainless steel, and combinations thereof.

[0043] According to one embodiment, the battery cell assembly 10 includes a thermal interface material (TIM) 60 disposed between the top surface 20b of the battery cell and a cooling plate 70. When the battery cell assembly 10 is in use, the top surface 20b of the battery assembly is heated. The TIM material then provides rapid heat transfer from the top surface 20b of the battery cell 20 to the cooling plate, and then distributes the heat along the TIM plate. Optionally, the TIM can be in the form of one or more thin films. Optionally, the TIM is in the form of an adhesive between the top surface 20b of the battery cell and the cooling plate 70. The thickness of the TIM plate can vary. The TIM plate is preferably thin enough to reduce thermal resistance.

[0044] According to one embodiment, the battery cell assembly has a battery height of approximately 135 mm. This height is given relative to the Z-axis shown in the figure. Known battery cell assemblies have a height of approximately 145 mm. Therefore, the configuration shown provides a more efficient arrangement for reducing battery height. Figure 1 and Figure 2 As shown, the height of the cooling plate 70 is approximately 5 mm, the height of the TIM60 is approximately 2 mm, the height of the battery cell is approximately 100 mm, the height of the frame 30 is approximately 25 mm, the height of the thermal protection plate 40 is approximately 1 mm, and the height of the base plate 50 is approximately 3 mm.

[0045] As discussed in the background section, by arranging the battery cell pack as shown, with the battery cells venting downwards rather than upwards toward the passenger compartment, no additional material or safety space is required to protect passengers in the event of a thermal event. Past configurations required a thermal protection plate between the battery cell 20 and the passenger compartment floor to protect passengers. By venting the batteries downwards, current batteries provide the necessary safety protection in a more comprehensive and efficient package (or compact form).

[0046] Figure 3 A schematic diagram of a battery pack 200 is shown. The battery pack 200 includes a plurality of battery cell groups 210 arranged in a stacked manner, such that the first terminals of the plurality of battery cell groups 210 are aligned to form a first terminal bar on the bottom side of the battery pack 200. The second terminals of the plurality of battery cell groups 210 are aligned to form a second terminal bar on the bottom side; and the vents of the plurality of battery cell groups 210 are aligned to form a vent bar on the bottom side. Each battery cell group in the plurality of battery cell groups 210 can correspond to... Figure 1 and Figure 2 Battery cell pack 10.

[0047] Capable of powering electric vehicles (see appendix) Figure 4 The electric vehicle provides such a battery pack 200 according to exemplary embodiments and / or any of the features described above. Furthermore, the electric vehicle can include a passenger compartment. Additionally, the battery pack 200 can be arranged below the passenger compartment. The electric vehicle can be an electric, hybrid, or plug-in hybrid vehicle. Therefore, the electric vehicle can be a pure electric vehicle or a hybrid vehicle. An electric vehicle typically includes at least one motor, but may include additional motors. The motor is configured to provide propulsion to the electric vehicle. Generally, the term "electric propulsion system" as used herein generally refers to vehicle electrical components used to provide energy (e.g., traction energy) and to store energy (transmit and receive energy). In other words, an electric propulsion system refers to a system configured to provide propulsion to an electric vehicle by converting electrical energy into mechanical energy, which is provided through an energy storage system such as the battery pack 200. In addition to the components mentioned above, the electric propulsion system may include additional components such as cables, sensors, control units, battery management units, etc. The electric propulsion system is configured to transmit and receive energy for providing propulsion to the vehicle and also for performing various vehicle operations.

[0048] Figure 4 An electric vehicle is shown, comprising a passenger compartment 300 and a battery pack 200 disposed below the passenger compartment 300. For ease of illustration, Figure 4Only some battery cell groups 10, 210 and parts of the frame 30 of the battery pack 200 are shown in the image to clearly show the first and second terminals 21a, 21b of each battery cell 20. Figure 4 The remaining parts of battery pack 200 and battery cell groups 10 and 210 are not shown.

[0049] exist Figure 4 As can be seen, the first and second terminals 21a and 21b are away from the crew compartment 300. In other words, the first and second terminals 21a and 21b face downwards.

[0050] Alternatively, this disclosure can be used in applications other than vehicles and passenger cars that use rechargeable battery packs as battery pack 200. For example, the battery pack 200 of this disclosure can be used in commercial vehicles or multi-purpose vehicles such as trucks and backup power storage.

[0051] However, these aspects may be embodied in many different forms and should not be construed as limiting; rather, these embodiments are provided by way of example so that this disclosure will be thorough and complete, and will fully convey the scope of all aspects of this disclosure to those skilled in the art. The same numbers refer to the same elements throughout the description.

Claims

1. A battery cell pack (10), comprising: - Battery cell (20), which includes first and second terminals (21a, 21b) located on the bottom side (20a) of the battery cell (20) and a vent (22), wherein the bottom side faces downward in the mounting position of the battery cell assembly; - A frame (30) on the bottom side of the battery cell, the frame (30) comprising: • Frame plate (32), comprising first and second openings (23a, 23b) aligned with the first and second terminals (21a, 21b) and a third opening (23c) aligned with the vent (22); and • First and second intermediate frame walls (34a, 34b) extending perpendicularly to the frame plate (32); - A heat protection plate (40) is disposed between the intermediate frame walls (34a, 34b), - wherein the intermediate frame wall (34a, 34b) contacts the thermal protection plate (40) to form a channel (80) between the terminals (21a, 21b) along the length of the bottom side (20a) of the battery cell (20).

2. The battery cell assembly (10) according to claim 1, wherein, Each of the two intermediate frame walls (34a, 34b) is disposed between one of the first and second openings (23a, 23b) for the terminals (21a, 21b) and the third opening (23a) for the vent (22).

3. The battery cell pack according to claim 1 or 2, wherein, The frame (30) also includes first and second end frame walls (36a, 36b) extending perpendicularly to the frame plate (32) and disposed on the end side of the bottom side (20a).

4. The battery cell pack according to claim 1 or 2, wherein, The frame (30) is made of plastic material.

5. The battery cell pack according to claim 1 or 2, wherein, The heat protection plate (40) comprises mica material.

6. The battery cell pack according to claim 1 or 2, wherein, The battery cell (20) is a rectangular battery cell.

7. The battery cell pack according to claim 1 or 2, wherein, The battery cell (20) is a prismatic battery cell.

8. The battery cell assembly according to claim 1 or 2 further includes a base plate (50) extending parallel to the bottom side (20a) of the battery cell (20) and contacting the first and second intermediate frame walls (34a, 34b).

9. The battery cell pack according to claim 8, wherein, The heat protection plate (40) is in contact with the base plate (50).

10. The battery cell pack according to claim 8, wherein, The base plate (50) contains aluminum.

11. The battery cell assembly according to claim 1 or 2, further comprising a cooling plate (70) disposed above the top side (20b) of the battery cell (20) opposite to the bottom side (20a).

12. The battery cell pack according to claim 11, wherein, The cooling plate (70) contains aluminum.

13. The battery cell assembly according to claim 11 further includes a thermal interface material TIM (60) between the top side (20b) of the battery cell (20) and the cooling plate (70).

14. A battery pack (200) comprising a plurality of battery cell groups (10) arranged in a stacked manner according to any one of the preceding claims, such that - The first and second terminals (21a, 21b) in a plurality of battery cell groups (10) are aligned to form first and second terminal blocks on the bottom side of the battery group; and - The vents (22) of multiple battery cell groups are aligned to form a vent row on the bottom side of the battery group.

15. An electric vehicle comprising a passenger compartment (300) and a battery pack (200) according to claim 14 located below the passenger compartment.

16. The electric vehicle according to claim 15, wherein, The first and second terminals (21a, 21b) of the plurality of battery cell groups (10) of the battery pack (200) are opposite to the occupant compartment.

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