Patent Description:
A battery module has a case, which is one of core components of the battery module, and the interior of which forms a space for accommodating battery cells. The case of a conventional battery module mainly includes a pair of side plates, a pair of end plates, a bottom plate and a top plate. The side plates and end plates mainly employ the following two structural forms.

In a first form, the side and end plates both are made of aluminum plates and are welded together. By adopting this structure, the weld strength between the side plates and the end plates is relatively low, resulting in a poor structural reliability of the battery module.

In a second form, the side and end plates both are made of steel plates and are welded together. Since steel plates are relatively heavy, the thickness of side and end plates are typically thin with less rigidity, causing the case of the battery module easily to be deformed due to the battery's expansion force. <CIT> discloses an end plate and battery module assembling. The end plate comprises metal pieces and a plastic piece fused with the metal pieces in an injection modeling mode, wherein the metal pieces are located on the side face of the plastic piece. <CIT> discloses a modular battery system having has at least one subsystem comprising a plurality of battery modules electrically connected. the modular battery system comprising: each subsystem having a first endplate and a second endplate, the battery modules bound between the first and second endplates; a data collection panel in electrical communication with each of the battery modules, the data collection panel transmitting status information of the modules to a master control module and the data collection panel transferring electrical current from the battery modules.

The present invention provides a battery module as defined in claim <NUM>, in order for improving the structural reliability of the battery module, while preventing the case of the battery module from being deformed due to the battery's expansion force.

According to the invention, the body is made of aluminum, and the connecting plates are made of steel.

In some embodiments, the body is provided with a mounting groove, which penetrates along the height direction of the battery module, and wherein the connecting plate is inserted into the mounting groove.

In some embodiments, the body has a first side surface and a second side surface, which are joined together and extend along the height direction of the battery module. The mounting groove includes a first groove and a second groove, both of which penetrate along the height direction of the battery module and are provided in the first side surface and the second side surface respectively. The opposite sides of the connecting plate are inserted into the first groove and the second groove respectively.

In some embodiments, the first groove is recessed along a width direction of the battery module.

In some embodiments, the second groove includes a lateral groove segment and a longitudinal groove segment, both of which are connected with each other and penetrate along the height direction of the battery module. The lateral groove segment is recessed along a width direction of the battery module, and the longitudinal groove segment is recessed along a length direction of the battery module.

Preferably, the connecting plates are in limiting fit with the body in the height direction of the battery module.

In some embodiments, a limiting protrusion is provided at an edge of the connecting plate, and a limiting groove is provided in the body, and the limiting protrusion is in limiting fit with the limiting groove in the height direction of the battery module.

In some embodiments, the limiting protrusion protrudes along one of the width direction of the battery module or the length direction of the battery module.

In some embodiments, the limiting protrusion protrudes along the length direction of the battery module, and there are a plurality of the limiting protrusions, which are distributed at intervals along the height direction of the battery module.

In some embodiments, at least two of the limiting protrusions protrude toward opposite directions. The battery module comprises side plates and end plates, wherein the end plates are fixedly connected to the side plates, and the end plates are implemented as the end plate of the battery module according to any of the above items.

The technical solutions provided in the present application can attain at least the following beneficial effects.

The end plate of the battery module provided in the present application includes a body and connecting plates. The materials of the body and the connecting plates are different. Thus, when the end plate of the battery module is designed, the body can utilize a lower density material, so that the thickness of the body can be appropriately increased, which enables the case of the battery module not easily to be deformed due to the battery's expansion force. Meanwhile, the connecting plates can employ a material capable of improving weld strength between the end plates and the side plates, thereby improving structural reliability of the batter module.

It is to be understood that both the foregoing general descriptions and the following detailed descriptions are only exemplary, and are not intended to limit the present application.

The drawings provided herein, which are incorporated in and constitute a part of the specification, illustrate embodiments consistent with the present application, and serve to explain the principles of the present application together with the description.

The present application will be further described in detail below by way of specific embodiments and in conjunction with the accompanying drawings.

As shown in <FIG>, the embodiments of the present application provide an end plate of a battery module, which may be fixedly connected to side plates <NUM> of the battery module. The end plate of the battery module includes a body <NUM> and connecting plates <NUM> which are connected to edges of body <NUM>. The edges of body <NUM> refer to the edges of body <NUM> close to the side plates <NUM> and are located at connecting positions between the entire end plate and the side plates <NUM> of the battery module. With respect to a single end plate of the battery module, there are typically two positions which are needed to be connected to side plates <NUM>. Thus, there may be two connecting plates <NUM>, which are connected to two opposite edges of the body <NUM> respectively.

The body <NUM> is mainly used to bear the battery's expansion force, provide mounting holes of the battery module and so on. The body <NUM> has a different material from that of connecting plates <NUM>, so that materials of the body <NUM> and the connecting plates <NUM> can be selected individually as needed without being limited by the structure of the end plates of the battery module. The connecting plates <NUM> extend along a height direction of the battery module (i.e., Z and -Z directions as shown in the coordinate system in <FIG>), and the body <NUM> is fixedly connected to the side plates <NUM> through the connecting plates <NUM>. In particular, the connecting plates <NUM> may be fixed to the side plates <NUM> by laser welding.

In an embodiment where the above end plate of the battery module is adopted, when the end plate of the battery module is designed, the body <NUM> employs a lower density material, that is, the density of body <NUM> is less than the density of the connecting plates <NUM>. On a premise of meeting a weight requirement, the thickness of the body <NUM> may be appropriately increased to improve rigidity of the end plate of the battery module, enabling the case of the battery module not easily to be deformed due to the battery's expansion force. Meanwhile, the connecting plates <NUM> may employ a material capable of improving the weld strength between the end plate and side plates <NUM> of the battery module, thereby improving the structural reliability of the batter module.

According to the present invention, the body <NUM> is made of aluminum, the connecting plates <NUM> are made of steel, and side plates <NUM> are steel plates. With such a design, it can be ensured that the body <NUM> has required weight on the premise of having a larger thickness. Moreover, by steel-steel welding of the connecting plates <NUM> and the side plates, the weld strength between the plates can be improved. Indeed, the selection of materials for the body <NUM> and the connecting plates is not limited to the foregoing scheme. For example, the body <NUM> may employ plastic cement, which may be polyphenylene sulfide, fiber reinforced plastics (FRP) and the like.

There are various ways to connect the body <NUM> and the connecting plates <NUM>, such as integrated injection molding. In order to improve structural strength of the end plate of the battery module, while to control its processing cost, the body <NUM> is provided with a mounting groove, which penetrates along the height direction of the battery module, and in which the connecting plates <NUM> is inserted. In this scheme, the body <NUM> and the connecting plates <NUM> are provided separately and then assembled together after being respectively processed. Such a structure can lead to a flexible processing for the body <NUM> and the connecting plates <NUM>, and more effectively improve the connecting strength between them, thereby achieving the aforementioned purpose. In particular, the body <NUM> may be implemented by way of aluminum extrusion and machining, and the connecting plates <NUM> may be implemented by way of press forming.

Further, as shown in <FIG>, the body <NUM> has a first side surface <NUM> and a second side surface <NUM> which are joined together and extend along the height direction of the battery module. The mounting groove includes a first groove <NUM> and a second groove <NUM>, which are opened in the first side surface <NUM> and the second side surface <NUM> respectively, and both of which penetrate along the height direction of the battery module. The opposite sides of connecting plates <NUM> are respectively inserted into the first groove <NUM> and the second groove <NUM>. As shown in <FIG>, with such an arrangement, the connecting plate <NUM> may include a first inserted portion <NUM>, a first exposed portion <NUM>, a second exposed portion <NUM> and a second inserted portion <NUM>, which are connected in turn. The first inserted portion <NUM> and the second inserted portion <NUM> are respectively inserted into the first groove <NUM> and the second groove <NUM>. The first exposed portion <NUM> and the second exposed portion <NUM> are respectively exposed relative to the first groove <NUM> and the second groove <NUM>, and may form a L-shaped structure. Such a structure results in relatively more connecting points between the connecting plates <NUM> and the body <NUM>, and thus is able to improve the connection strength and the relative positioning accuracy between them.

In order to further improve the relative positioning accuracy between the connecting plates <NUM> and the body <NUM>, the first groove <NUM> may be recessed along a width direction of the battery module (i.e., Y and -Y directions as shown in the coordinate system in <FIG>) with respect to the first side surface <NUM>, in order for more effectively preventing the connecting plates <NUM> and the body <NUM> from shifting relatively along a length direction of the batter module (i.e., X and -X directions as shown in the coordinate system in <FIG>).

For the structural design of the second groove <NUM>, the following scheme is preferable by the embodiments of the present application. The second groove <NUM> includes a longitudinal groove segment 103a and a lateral groove segment 103b, both of which are connected with each other and penetrate along the height direction of the battery module. The longitudinal groove segment 103a is recessed along the length direction of the battery module with respect to the aforementioned second side surface <NUM>, and the lateral groove segment 103b is recessed along the width direction of the battery module. As such, the relative shift and flip of the connecting plates <NUM> and the body <NUM> may be limited in both the length and width directions of the battery module at the same time by fitting of the second inserted portion <NUM> of the connecting plate <NUM> with the second groove <NUM>, and thus the positioning accuracy between the connecting plates <NUM> and the body <NUM> can be greatly improved.

Upon the connecting plates <NUM> being inserted into the body <NUM>, the bottom edge of connecting plates <NUM> can be aligned with that of the body <NUM>, and thus the bottom plate of the battery module can be used to limit displacement between the connecting plates <NUM> and the body <NUM> in the height direction of the battery module. However, merely by this way, there is still a possibility that the connecting plates <NUM> move upwards with respect to the body <NUM>. In order to prevent an occurrence of such a situation, the embodiments of the present application preferably employ the following way: the connecting plates <NUM> are in limiting fit with the body <NUM> in the height direction of the battery module. That is to say, the relative movement between the connecting plates <NUM> and the body <NUM> can be limited in two opposite directions along the height direction.

In an embodiment, a limiting protrusion <NUM> may be provided at an edge of the connecting plate <NUM>. A limiting groove may be provided in the body <NUM>, and generally connected to the mounting groove. The limiting protrusion <NUM> is in limiting fit with the limiting groove. In particular, the limiting protrusion <NUM> may protrude along the width direction of the battery module. As such (shown in <FIG>), the limiting protrusion <NUM> is in limiting fit with the floor of the groove. More preferably, the limiting protrusion <NUM> may be provided at the top position of the connecting plate <NUM>. Instead, the limiting protrusion <NUM> may protrude along the length direction of the battery module. As such, the limiting groove is also recessed along the length direction of the battery module. The limiting protrusion <NUM> and the limiting groove may be in transition fit with each other to strengthen the limiting effect. In addition, the latter way may further avoid molding the limiting groove in body <NUM> by machining, thus simplifying the procedure for processing the end plates of the battery module.

In case that the limiting protrusion <NUM> protrudes along the length direction of the battery module, there may be a plurality of the limiting protrusions <NUM>, which are distributed at intervals along the height direction of the battery module. With such arrangement, the number of limiting fit points between the connecting plates <NUM> and the body <NUM> can be increased, while distribution of the limiting fit points can be optimized, so that the limiting effect of the limiting protrusion <NUM> will be more effective, and thereby the relative positioning accuracy between the connecting plates <NUM> and the body <NUM> can be improved. Further, at least two of the plurality of the limiting protrusions <NUM> protrude towards opposite directions, that is, protruding along X and -X directions as shown in <FIG> to make the limiting force between the connecting plate <NUM> and the body <NUM> more evenly distributed on both of them, preventing the connecting plate <NUM> and the body <NUM> from tilt, local deformation and the like due to unilateral stress.

Claim 1:
A battery module comprising:
an end plate; and
side plates (<NUM>);
characterized in that the end plate comprises:
a body (<NUM>); and
connecting plates (<NUM>) connected to edges of the body (<NUM>),
wherein the connecting plates (<NUM>) extend along a height direction of the battery module, and the body (<NUM>) is fixedly connected to the side plates (<NUM>) of the battery module through the connecting plates (<NUM>) by laser welding,
wherein the body (<NUM>) is made of aluminum, the connecting plates (<NUM>) are made of steel, and the side plates (<NUM>) are made of steel.