Busbars for battery packs
Patent Information
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- TVS MOTOR CO LTD
- Filing Date
- 2023-02-13
- Publication Date
- 2026-07-15
AI Technical Summary
Conventional busbars in lithium-composite batteries fail to disconnect cells from each other and terminals during elevated temperatures, leading to potential fires and explosions, even when the Battery Management System (BMS) malfunctions.
The busbar design incorporates Shape Memory Alloys (SMAs) for the component connector and connection controller, which change shape in response to temperature, disconnecting the busbar from cells and terminals when temperatures exceed critical levels, preventing current flow and thus preventing overheating and potential fires.
This design effectively prevents battery pack fires and explosions by automatically disconnecting the busbar at elevated temperatures, even if the BMS fails, ensuring safety and resuming current supply when temperatures drop, without the need for external intervention.
Smart Images
Figure 1.1
Abstract
Description
BUSBARS FOR BATTERY PACKSFIELD OF INVENTION
[0001] The present subject matter relates, in general, battery packs and in particular, to busbars for battery packs.BACKGROUND
[0002] Battery, such as a Lithium (Li)-composite battery, is used to power components in applications, such as electric vehicles, hybrid vehicles, and the like. The battery has a plurality of cells in electrical connection with each other. A busbar enables connection between the plurality of cells of the battery and main terminals of battery. The Li-composite battery includes highly flammable compounds. Therefore, when temperature of such Li- composite battery achieves elevated temperatures due to unintended events, such as thermal failure, mechanical failure, internal short circuiting, external short circuiting, and the like, explosion may occur.
[0003] In conventional Li-composite batteries, to prevent the batteries from explosion, the batteries are provided with safety mechanisms. For instance, a battery includes a Battery Management System (BMS) that controls current of the battery, and therefore, controlling temperature of the battery. Particularly, the BMS shuts down the battery whenever unintended events occur. Therefore, the BMS prevent the battery from catching fire and causing explosion.BRIEF DESCRIPTION OF DRAWINGS
[0004] The detailed description is provided with reference to the accompanying figures. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. Thesame numbers are used throughout the drawings to reference like features and components.
[0005] Fig. 1 illustrates an exploded view of a battery pack, in accordance with an implementation of the present subject matter;
[0006] Fig. 2a illustrates a perspective view of a busbar of a battery pack, in accordance with an implementation of the present subject matter;
[0007] Fig. 2b illustrates a side view of a busbar of a battery pack, in accordance with an implementation of the present subject matter;
[0008] Fig. 3 illustrates a component connector of a busbar of a battery pack, in accordance with an implementation of the present subject matter;
[0009] Fig. 4 illustrates a component connector of a busbar of a battery pack, in accordance with an implementation of the present subject matter;
[0010] Fig. 5 illustrates a connection controller of a battery pack, in accordance with an implementation of the present subject matter; and
[0011] Fig. 6 illustrates a connection controller of a battery pack, in accordance with an implementation of the present subject matter.DESCRIPTION
[0012] A Battery has a plurality of cells in electrical connection with each other. A busbar enables connection between the plurality of cells of the battery with terminals of battery. During operation, each cell generates heat and thereby, increasing the temperature of the battery. However, such heat is dissipated to ensure that the temperature of the battery is below a critical temperature and thereby, ensuring proper operation of the vehicle. When temperature of the battery achieves elevated temperatures due to unintended events, such as thermal failure, mechanical failure, internal short circuiting, external short circuiting, and the like, the battery may catch fire and explode. Particularly, batteries, such as Lithium (Li)-composite battery includes highlyflammable compounds. When the temperature of one or more cells of the Li- composite battery exceeds the critical temperature, conventional busbars do not disconnect the one or more cells from the other cells and / or from the terminals of the battery. Accordingly, the circuit of the battery is not broken physically. Therefore, the Li-composite batteries catch fire and explode. Such explosion of Li-composite batteries may cause malfunction or damage in the applications they are used in, such as electric vehicles, hybrid vehicles, and the like. For instance, the whole electric vehicle may catch fire as a result of battery explosion.
[0013] In conventional Li-composite batteries, to prevent the batteries from explosion, the batteries are provided with safety mechanisms. For instance, a battery includes a Battery Management System (BMS) that controls current of the battery, and therefore, controlling the temperature of the battery. Particularly, the BMS shuts down the battery whenever unintended events occur. Therefore, the BMS prevent the battery from catching fire and causing explosion. However, if the BMS malfunctions, the conventional batteries achieve elevated temperatures and catch fire.
[0014] The present subject matter relates to busbars for battery packs. With the implementations of the present subject matter, fire hazards and explosion of battery packs can be eliminated. Further, the safety of the battery packs is enhanced with the present subject matter.
[0015] In accordance with an example implementation, a busbar may be used in a battery pack. The battery pack may be, for example, a Lithium (Li)-composite battery pack. The busbar may include a longitudinal body, a plurality of projections, and an interconnector terminal. The plurality of projections may extend substantially orthogonally with respect to the longitudinal body. Each projection from amongst the plurality of projections may be connectable to a cell of the battery pack. The projection may includea tail portion and a head portion. The tail portion may connect the projection to the longitudinal body. The head portion may be contiguous with the tail portion. The head portion may connect to the cell. The interconnector terminal may electrically connect the busbar to another component. In an example, the component may be a base plate. The base plate may connect the busbar with main terminals of the battery pack. In other words, the base plate enables transferring current from each of the plurality of cells to the main terminals of the battery pack through the busbar. The interconnector terminal may include a component-facing surface and a component connector. The component connector may be disposed on the component-facing surface. The component connector may be made of a Shape Memory Allow (SMA) and may be electrically conductive. The component connector may be, for example, may be in shape of a truncated sphere, in a deformed shape. In an original shape, the component may be of flat-shape.
[0016] During operation, when the temperature of the one or more cells exceeds a critical temperature, and the battery temperature exceeds the critical temperature. The component connector may change its shape to attain its original shape from the deformed shape. For instance, the component connector may become flat-shaped from being truncated-sphere shape. Accordingly, the component connector may cease to connect the base plate with the busbar. This position may be referred to as the disconnected position. In the disconnected position, the current supply to the main terminals of the battery pack is stopped, as the cells provide current to the main terminals through the base plate and the busbar. This prevents the battery pack to overheat and thereby, preventing a fire hazard. When the temperature of the battery pack decreases below a critical temperature, the component connector may return back to the deformed shape, i.e., the truncated-sphere shape. Therefore, the component connector may connectthe base terminal and the busbar, which may enable current supply from the cells to the terminals of the battery pack.
[0017] In another example, each projection from amongst the plurality of projections may be connectable to a cell of the battery pack. The head portion of each projection may have a cell-facing surface. The head portion may be bendable with respect to the longitudinal body to be movable between a connected position and a disconnected position by a connection controller. In the connected position, the busbar is connected with the cells. Therefore, the busbar may provide current supply from the cells to the main terminals. In the disconnected position, the busbar is disconnected from the cells. Therefore, the busbar may not provide current supply from the cells to the main terminals.
[0018] The connection controller may be for example, made of a Shape Memory Alloy (SMA). In particular, the connection controller may be of spring-shaped, or the like. In the connected position, the connection controller may be in an extended state and in the disconnected position, the connectioncontroller may be in a contracted state.
[0019] During operation, when the temperature of the one or more cells exceeds the critical temperature, and the battery pack temperature exceeds the critical temperature. In response, the connection controller may contract. Therefore, the connection controller may cease to connect the busbar with the cells. In the disconnected position of the busbar and the cells, the current supply to the main terminals is stopped, as the cells provide current to the main terminals through the busbar. This prevents the battery pack to overheat and thereby, preventing a fire hazard. When the temperature of the battery pack decreases below the critical temperature, the connection controller may extend to connect the busbar with the cells. In particular, the head portion of a projection of the busbar may bend to connect with the corresponding cell.Therefore, the connection controller may connect the busbar and the cells, which may enable current supply from the cells to the main terminals of the battery pack.
[0020] In the present subject matter, when the temperature of one or more cells of a battery pack exceeds a critical temperature, the component connector prevents connection of the busbar and the base plate. Similarly, in some examples, when the temperature of one or more cells of a battery pack exceeds a critical temperature, the connection controller may cease to connect the busbar with the cells of the battery pack. This prevents the current flow in the battery pack when the temperature of the battery pack achieves elevated temperatures. Therefore, with the present subject matter, fire hazard and explosion of the battery pack can be eliminated. In particular, the present subject matter prevents explosion or the fire hazards of the battery pack even if the battery management system of the battery pack malfunctions. Accordingly, the present subject matter enhances safety of the battery pack. When the temperature of the battery pack reduces below the critical temperature, the current supply resumes again in the battery pack automatically without any external intervention. Therefore, the present subject matter prevents disassembly of the battery pack to service the battery pack to restore its operation. The present subject matter uses simple design and therefore, is easy to assembly. The component connector and the connection controller also require less space in the battery pack.
[0021] The present subject matter is further described with reference to Figs. 1 -6. It should be noted that the description and figures merely illustrate principles of the present subject matter. Various arrangements may be devised that, although not explicitly described or shown herein, encompass the principles of the present subject matter. Moreover, all statements herein reciting principles, aspects, and examples of the present subject matter, aswell as specific examples thereof, are intended to encompass equivalents thereof.
[0022] Fig. 1 illustrates an exploded view of a battery pack 100, in accordance with an implementation of the present subject matter. The battery pack 100 may include a plurality of cells 102. Each of the plurality of cells 102 may be in electrical connection with each other. In an example, the plurality of cells 102 may be in series connection or in parallel connection. The plurality of cells 102 may be, for example, Lithium-composite (Li-composite) cells, a nickel hydrogen battery, or the like. Accordingly, the battery pack 100 may be Li-composite battery pack, nickel hydrogen battery pack, and the like. Hereinafter, the battery pack 100 will be explained with reference to the Li- composite battery pack.
[0023] The battery pack 100 may include a busbar 104 to enable connection between the plurality of cells 102 of the battery pack 100 and with main terminals of the batte y pack 100. For instance, the busbar 104 may supply current from each of the plurality of the cells 102 to main terminals (not shown in Fig. 1 ) of the battery pack 100. In an example, the busbar 104 may supply current to the main terminals through a base plate (not shown in Fig. 1 ). Accordingly, the busbar 104 may be made of an electrically conductive material. The busbar 104 may be, for example, a one-way busbar or a two- way busbar. In a one-way busbar, electrical current may only be supplied from the busbar 104 to a component, such as battery management system (BMS) 106. In a two-way busbar, electrical current can be supplied from as well as received by the busbar 104 from the BMS 106.
[0024] The battery pack 100 may include the BMS 106 that controls the operations of the battery pack 100. Particularly, the BMS 106 may monitor and control the input and output of the current supply to the battery pack 100. The BMS 106 may also monitor and control parameters, such as current,temperature, and the like, of the plurality of cells 102 in the battery pack 100. The BMS 106 transmits the electric current supplied to the busbar 104 from the cells 102 to the main terminals. When unintended events, such as such as thermal failure, mechanical failure, internal short circuiting, external short circuiting, and the like, explosion occurs, the BMS 106 stops current supply to the main terminals and thereby, controls the temperature of the battery pack 100. However, if the BMS 106 malfunctions, the battery pack 100 may achieve elevated temperatures and catch fire. Accordingly, the battery pack 100 may include a component connector and a connection controller, as will be described below with reference to Figs. 3-6.
[0025] The battery pack 100 may include a battery frame 108 to provide a cover and to protect components of the battery pack 100, such as the plurality of cells 102. The battery frame 108 may include a top cover 110, a bottom cover 112, and side covers 114 114, to cover the components of the battery pack 100 from all sides.
[0026] Fig. 2a illustrates a perspective view of the busbar 104 of the battery pack 100, in accordance with an implementation of the present subject matter. Fig. 2b illustrates a side view of the busbar 104 of a battery pack 100, in accordance with an implementation of the present subject matter. For the sake of brevity and ease of understanding, Fig. 2a and Fig. 2b are described in conjunction with each other. The busbar 104 may include a longitudinal body 202. In an example, the longitudinal body 202 may be of substantially rectangular shape. However, in other examples, the longitudinal body 202 may be of other shapes, such as substantially elliptical shape, U- shaped, and the like.
[0027] The busbar 104 may have a plurality of projections 204. Each projection 204 may extend substantially orthogonally with respect to the longitudinal body 202. Each projection 204 from amongst the plurality ofprojections 204 may be connectable to a cell 102 of the battery pack 100. The projection 204 may enable supplying current from the corresponding cell 102 (not shown in Figs. 2a and 2b) to the main terminals (not shown in Figs. 2a and 2b) of the battery pack 100.
[0028] Each projection 204 may include a tail portion 206 and a head portion 208. The tail portion 206 may connect the projection 204 to the longitudinal body. The head portion 208 may be contiguous with the tail portion 206. The head portion 208 may connect to the cell 102. The current from the cell 102 may be supplied through the head portion 208. The busbar 104 may include an interconnector terminal 210 to electrically connect the busbar 104 to another component.
[0029] Fig. 3 illustrates a component connector 302 of the busbar 104 of the battery pack 100, in accordance with an implementation of the present subject matter. The interconnector terminal 210 may include a componentfacing surface 304 that may face at least a face of the component 306. In an example, the component may be the base plate. The base plate may enable connection of the busbar 104 with the terminals of the battery. Hereinafter, the component will be explained with reference to the base plate. The interconnector terminal 210 may include a component connector 302 disposed on the component-facing surface 304. The component connector 302 may enable connection and disconnection of the busbar 104 with the base plate 306 to enable or prevent current supply to the main terminals of the battery pack 100 from the plurality of cells 102. Accordingly, the component connector 302 may be electrically conductive. Further, in an example, the component connector 302 made of a shape memory allow (SMA). As will be understood, the SMA is a metal that will be deformed at a lower temperature and return to their original shape before deformation simply by being heated. In an example, in a deformed shape, the componentconnector 302 may be of truncated sphere. However, in other examples, in a deformed shape, the component connector 302 may be of cone-shaped, cube-shaped, cuboid-shaped, trapezoidal-shaped, semi-elliptical shaped, and the like.
[0030] During operation, when the temperature of the battery pack 100 operates below a critical temperature, the component connector 302 may be in a deformed shape, i.e., in a shape, such as a truncated-sphere, as is shown herein. Therefore, in such a state, the component connector 302 may connect the base terminal and the busbar 104. This may enable current supply from the cells 102 to the terminals of the battery. In an example, the critical temperature may be about 60° C.
[0031] Fig. 4 illustrates the component connector 302 of the busbar 104 of the battery pack 100, in accordance with an implementation of the present subject matter. During operation, when the temperature of the one or more cells 102 exceeds the critical temperature, the temperature of the battery pack 100 exceeds the critical temperature. In this regard, the component connector 302 may change its shape to attain its original shape from the deformed shape. For instance, the component connector 302 may become flat-shaped from being truncated-sphere shape due to increase in temperature. Accordingly, the component connector 302 may cease to connect the base plate 306 with the busbar 104, which may be referred to as the disconnected position. In the disconnected position, the current supply to the main terminals (not shown in Fig. 4) of the battery pack 100 is stopped, as the cells 102 provide current to the main terminals through the base plate 306 and the busbar 104. This prevents the battery pack 100 to overheat and thereby, preventing a fire hazard. When the temperature of the battery pack 100 decreases below the critical temperature, the component connector 302 may be return back to its deformed shape, i.e., the truncated-sphere shape.Therefore, the component connector 302 may connect the base plate 306 and the busbar 104, which may enable current supply from the cells 102 to the main terminals, as is shown and explained with reference to Fig. 3.
[0032] In some examples, instead of the component connector 302, to prevent the current flow in the battery pack 100 when the temperature of the battery pack 100 achieves elevated temperatures, the battery pack 100 may include a connection controller, as will be described below.
[0033] Fig. 5 illustrates a connection controller 502 of the battery pack 100, in accordance with an implementation of the present subject matter. In some examples, the battery pack 100 may include a connection controller 502 that may control engagement or disengagement of the busbar 104 with the corresponding cell 102. Accordingly, the connection controller 502 may enable or prevent current supply from the corresponding cell 102 to the busbar 104. In an example, the connection controller 502 may control engagement and disengagement of the head portion 208 with the cell 102. In this regard, the head portion 208 may include cell-facing surface 504 that is to face the corresponding cell 102. In an example, the head portion 208 may be disengageably-engagable with the cell 102.
[0034] The connection controller 502 may be made of a Shape Memory Alloy (SMA). In an example, the connection controller 502 may be in shape of a helical spring. Particularly, the connection controller 502 may be in shape of helical compression spring. However, in other examples, the connection controller 502 may be in a shape of circular coil spring, or the like. The SMA may be in an extended state at a lower temperature (i.e., at a temperature below the critical temperature) and return to its original shape before deformation by being heated (i.e., to a contracted state). The connection controller 502 may be fixedly mounted to the battery frame 108. Inan example, the connection controller 502 may be fixedly mounted to the side covers 1 14.
[0035] During operation, when the temperature of the battery pack 100 is below the critical temperature, the connection controller 502 may extend to connect the busbar 104 with the cells 102. In particular, the head portion 208 of the projection 204 may bend to connect with the corresponding cell 102. Therefore, the connection controller 502 may connect the busbar 104 and the cells 102, which may enable current supply from the cells 102 to the terminals of the battery.
[0036] Fig. 6 illustrates the connection controller 502 of the battery pack 100, in accordance with an implementation of the present subject matter. During operation, when the temperature of the one or more cells 102 exceeds the critical temperature, the temperature of the battery pack 100 exceeds the critical temperature. In response, the connection controller 502 may contract due to spring force. Therefore, the connection controller 502 may cease to connect the busbar 104 with the cells 102. In the disconnected position of the busbar 104 and the cells 102, the current supply to the main terminals of the battery pack 100 is stopped, as the cells 102 provide current to the main terminals through the busbar 104. This prevents the battery to overheat and thereby, preventing a fire hazard.Further, when the temperature of the battery pack 100 drops below the critical temperature, the connection controller 502 may again extend to connect the busbar 104 with the cells 102. Therefore, the connection controller 502 may connect the busbar 104 and the cells 102, which may enable current supply from the cells 102 to the terminals of the battery, as is shown and explained with reference to Fig. 6.
[0038] Although in the above examples, to prevent the current flow in the battery pack 100 when the temperature of the battery pack 100 achieveselevated temperatures, the battery pack 100 was explained to include the connection controller 502 instead of the component connector 302. In some examples, the battery pack 100 may include the connection controller 502 in addition to the component connector 302 for preventing the battery pack 100 from fire hazard and explosion.
[0039] In the present subject matter, when the temperature of one or more cells of a battery pack exceeds a critical temperature, the component connector prevents connection of the busbar and the base plate 306. Similarly, in some examples, when the temperature of one or more cells of a battery pack exceeds a critical temperature, the connection controller may cease to connect the busbar with the cells of the battery pack. This prevents the current flow in the battery pack when the temperature of the battery pack achieves elevated temperatures. Therefore, with the present subject matter, fire hazard and explosion of the battery pack can be eliminated. In particular, the present subject matter prevents explosion or the fire hazards of the battery pack even if the battery management system of the battery pack malfunctions. Accordingly, the present subject matter enhances safety of the battery pack. When the temperature of the battery pack reduces below the critical temperature, the current supply resumes again in the battery pack automatically without any external intervention. Therefore, the present subject matter prevents disassembly of the battery pack to service the battery pack to restore its operation. The present subject matter uses simple design and therefore, is easy to assembly. The component connector and the connection controller also require less space in the battery pack.
[0040] Although the present subject matter has been described with reference to specific embodiments, this description is not meant to be construed in a limiting sense. Various modifications of the disclosed embodiments, as well as alternate embodiments of the subject matter, willbecome apparent to persons skilled in the art upon reference to the description of the subject matter.
Claims
We claim:1 . A busbar (104) for a battery pack (100), the busbar (104) comprising: a longitudinal body (202); a plurality of projections (204) extending substantially orthogonally with respect to the longitudinal body (202), each projection (204) from amongst the plurality of projections (204) connectable to a cell (102) of the battery pack (100), the projection (204) having:a tail portion (206) to connect the projection (204) to the longitudinal body (202); anda head portion (208) contiguous with the tail portion (206), the head portion (208) to connect to the cell (102); and an interconnector terminal (210) to electrically connect the busbar (104) to another component, the interconnector terminal (210) comprising:a component-facing surface (304); and a component connector (302) disposed on the componentfacing surface (304), the component connector (302) made of a Shape Memory Allow (SMA) and being electrically conductive.
2. The busbar (104) as claimed in claim 1 , wherein the busbar (104) is made of an electrically conductive material.
3. The busbar (104) as claimed in claim 1 , wherein the busbar (104) is a one-way busbar (104).
4. The busbar (104) as claimed in claim 1 , wherein the busbar (104) is a two-way busbar (104).
5. The busbar (104) as claimed in claim 1 , wherein the component connector (302) is in shape of a truncated sphere.
6. A battery pack (100) comprising: a battery frame (108); a plurality of cells (102), each of the plurality of cells (102) having a terminal; anda busbar (104) to connect terminals of the plurality of cells (102), wherein the busbar (104) comprises: a longitudinal body (202);a plurality of projections (204) extending substantially orthogonally with respect to the longitudinal body (202), each projection (204) from amongst the plurality of projections (204) connectable to a cell (102) of the battery pack (100), the projection (204) having:a tail portion (206) to connect the projection (204) to the longitudinal body (202); and a head portion (208) contiguous with the tail portion (206) and having a cell-facing surface (504), wherein at least the head portion (208) is disengageably engagable with the cell (102) of the battery pack (100); and a connection controller (502) made of a shape memory alloy ) and fixedly mounted to the battery frame (108), whereinonnection controller (502) is to control engagement and disengagement of the head portion (208) with the cell (102).
7. The battery pack (100) as claimed in claim 6, wherein the connection controller (502) is in shape of a helical spring.
8. The busbar (104) as claimed in claim 6, wherein the busbar (104) is a one-way busbar.
9. The busbar (104) as claimed in claim 6, wherein the busbar (104) is a two-way busbar.
10. A busbar (104) for a battery pack (100), the busbar (104) comprising: a longitudinal body (202); a plurality of projections (204) extending substantial orthogonally with respect to the longitudinal body (202), e projection (204) from amongst the plurality of projectionsconnectable to a cell (102) of the battery pack (100), the projection (204) having:a tail portion (206) to connect the projection (204) to the longitudinal bodya head portion (208) contiguous with the tail portion (206) and having a cell-facing surface (504), wherein at least the head portion (208) is bendable with respect to the longitudinal body (202) to be movable between a connected and a disconnected position by a connection controller (502) made of a shape memory alloy (SMA).