CN114846683A

CN114846683A - Battery pack

Info

Publication number: CN114846683A
Application number: CN202080088203.4A
Authority: CN
Inventors: C.加斯克尔
Original assignee: Dyson Technology Ltd
Current assignee: Dyson Technology Ltd
Priority date: 2019-12-19
Filing date: 2020-10-14
Publication date: 2022-08-02
Also published as: WO2021123716A1; GB2590465A; GB2590465B; GB201918806D0

Abstract

A battery pack (1) has a first battery module and a second battery module arranged side by side within the battery pack, and an inter-module connector (6, 7, 8, 9) connecting the first battery module and the second battery module. Each battery module (2) has terminals (4, 5) extending upward beyond the upper surface of the battery module (2), and the inter-module connectors (6, 7, 8, 9) are connected to the respective terminals (4, 5) and pass through the respective upper surfaces of the first and second battery modules (2).

Description

Battery pack

Technical Field

The present invention relates to a battery pack including a battery module. The battery pack is suitable for electric vehicles and other uses.

Background

The market for battery packs is growing, especially for electric vehicles. Typically, a battery pack may include a number of battery cells, and groups of battery cells may be packaged in the battery pack into a battery module. The battery modules may be interconnected by bus bars. The battery modules and bus bars are desirably packaged within a battery pack to provide high energy storage density, light weight, and safe operating characteristics during manufacture, use, and maintenance.

Disclosure of Invention

According to a first aspect of the present invention, there is provided a battery pack including: a first battery module and a second battery module arranged side by side in a battery pack; and an inter-module connector connecting the first battery module and the second battery module, wherein each battery module has a terminal extending upward beyond an upper surface of the battery module, and the inter-module connector is connected to the corresponding terminal and passes through the corresponding upper surfaces of the first battery module and the second battery module.

The terminals extending upward beyond the upper surface of the battery module may allow inter-module connectors (e.g., elongated bus bars that are substantially planar) to pass through the upper surface of the battery module while being connected to the module by an easily accessible and convenient connection. This can prevent an extra length of the inter-module connector, which is required if the terminals are disposed at a position below the upper surface of the battery module (e.g., connected with the inter-module connector on the side of the battery module) and the inter-module connector is disposed on the upper surface of the battery module. Extending the inter-module connectors over the upper surface of the module may provide a larger area to arrange the inter-module connectors, allowing the inter-module connectors to be spaced more apart, thereby reducing the chance of shorting. Furthermore, this enables the inter-module connections to be shorter when connecting to the front and rear of the battery pack, as compared to the case where the inter-module connections are routed around the sides of the battery modules. Routing the inter-module connections on the upper surface of the battery module may be preferable to routing the inter-module connectors on the side surfaces or the bottom surface because there is less chance of a short circuit in the event of a side impact or a bottom intrusion.

Furthermore, the terminals extending upward beyond the upper surface of the battery module allow for more efficient use of space than the recessed connection terminals, allowing for an increase in the length of the battery module that may be occupied by the battery cells, thereby increasing the energy density of the module. A female connection terminal generally requires a reduction in the bus bar to terminal connection height, which can result in unusable space due to the bend radius required to turn the bus bar, thus reducing the energy density of the module.

The battery pack may include a plurality of battery modules, including a first battery module and a second battery module, arranged in a row along a length of the battery pack. The terminals of each of the first and second battery modules may be disposed closer to a first side of the row and farther from the other side of the row.

This arrangement may provide a compact layout without crossovers of inter-module connections, while leaving empty areas between inter-module connections on each side of the row of modules that may be used to route circuitry associated with the battery pack, such as battery management circuitry.

Each terminal may be disposed at a side edge of the corresponding battery module. This enables a greater area available on the top surface of the battery module for routing inter-module connections and routing circuitry associated with the battery pack.

The row of battery modules may be arranged from the front to the rear of the battery pack, the plurality of battery modules being configured such that, in use, current flows along a current path from the front to the rear of the battery pack through a first sub-group of modules in the row, and from the rear to the front of the battery pack through a second sub-group of modules in the row, wherein at least one module of the second sub-group is located between at least two modules of the first sub-group.

This arrangement may allow both ends of the current path through the row of battery modules to be located at the same end of the battery pack while providing shorter connections between each module, thereby reducing the need for additional support for the bus bars and reducing the effects of thermal expansion during use.

The plurality of battery modules may be arranged as pairs of adjacent modules along the row, the modules of each pair being electrically connected together directly in series. This may allow for shorter connections between each module, thereby avoiding the need to provide longer inter-module connections. Reducing the required inter-module connection length may reduce mass and cost. Longer inter-module connections generally require more support and may also have greater thermal expansion problems when used.

The first sub-group of modules may be connected to the second sub-group of modules by a current interrupt device at the rear of the battery pack. The current interruption device may comprise a fuse, and/or may comprise a switch.

Arranging the battery modules in two subsets and arranging the current interruption means between the subsets may enable a safe disconnection of the two subsets, thereby limiting the maximum voltage difference between any two points in the row of modules for a safer operation. Arranging the fuses between the two subsets may enable an arrangement that prevents short circuits between the bus bars associated with the different subsets. Arranging the current interrupt device at the rear of the battery pack may enable a more compact arrangement, as compared to the case where the current interrupt device is arranged between the middle modules within the battery pack, because the battery modules may be packed more closely, and the end portions of the battery pack may be tapered, thereby providing a space for the current interrupt device between the tapered portions. This also allows for easy access to the fuses and/or switches during maintenance.

The battery modules in the row may be arranged such that adjacent battery modules in the row have terminals of opposite polarity on the first side of the row. In some arrangements, this can allow interconnection of the battery modules without crossing the bus bars, which reduces the requirement for insulation between the bus bars and allows channels for routing other circuitry to be provided along the length of the battery pack without crossing the bus bars. For example, the battery pack may include battery management circuitry disposed along the row of battery modules in a region between a bus bar on a first side of the row of battery modules and a bus bar on an opposite side of the row of battery modules.

The battery pack may comprise a further plurality of battery modules arranged in a further row from the front to the rear of the battery pack, wherein the further plurality of modules is configured such that, in use, current flows along a further current path from the front to the rear of the battery pack through a third sub-group of the further plurality of battery modules and from the rear to the front of the battery pack through a fourth sub-group of the further plurality of battery modules, wherein at least one module of the fourth sub-group is located between at least two modules of the third sub-group.

The row and the further row may have the same overall arrangement of battery modules. In particular, each row may be composed of the same number, type and orientation of modules, providing a balanced design in terms of weight distribution and matching resistance characteristics, in order to achieve load balancing with the rows connected in parallel.

The battery pack is switchable between a first configuration in which the plurality of battery modules are connected in series with the further plurality of battery modules and a second configuration in which the plurality of battery modules are connected in parallel with the further plurality of battery modules.

This arrangement can allow different charging and/or discharging voltages to be selected. The inter-module connector may be an elongated bus bar that is substantially planar. This can provide a space-saving inter-module connector when the inter-module connector is arranged on the upper surface of the battery module.

Each terminal may have an aperture substantially aligned with an upper surface of a respective battery module, the aperture configured to receive a bus bar. This can provide a space-saving arrangement for connecting the bus bars to the battery module without the need to change the height, which would otherwise require the provision of straps in the bus bars in order to achieve a change in height.

Each terminal may have an electrically insulative cover arranged to cover at least a portion of the bus bar adjacent the aperture. This arrangement allows the bus bar to have an uninsulated section at the end of the bus bar near the terminal, due to the protection of the electrically insulating cover, to allow an effective electrical connection to be made between the bus bar and the terminal without electrical risk.

Each terminal may protrude from a side edge of the respective module, and the aperture may face the respective battery module. This arrangement enables efficient routing of the bus bars on the top surface of the battery module.

The terminals may have a substantially rectangular cross-section in the plane of the top surface of the respective battery module. This enables the substantially rectangular end of the bus bar to be efficiently accommodated.

An electric vehicle may include a battery pack as described in any preceding paragraph.

The battery pack as described in the preceding paragraph is particularly suitable for use in an electric vehicle.

Other features and advantages of the present invention will become apparent from the following description of examples thereof, which is made with reference to the accompanying drawings.

Drawings

In order that the invention may be more readily understood, examples of the invention will now be described with reference to the accompanying drawings, in which:

fig. 1 is a schematic plan view of a battery pack of an example, showing the arrangement of battery modules;

fig. 2 is a schematic view of a battery module of the battery pack of fig. 1;

FIG. 3 is a schematic view of the battery pack of FIG. 1 showing the arrangement of bus bars interconnecting the battery modules;

FIG. 4 is a schematic view of the battery pack of FIG. 1 showing a battery management circuit disposed in the area between the bus bars;

FIG. 5 is a perspective view of a portion of the battery pack of FIG. 1 showing a barrier of insulating material disposed between a bus bar connected to a terminal of one row of battery modules and another bus bar connected to a terminal of an adjacent row of battery modules;

fig. 6 is a top view of an insulating tray carrying electrical components of the battery pack of fig. 1, the insulating tray providing a barrier of insulating material between adjacent bus bars;

FIG. 7 is a perspective view of a terminal disposed at a side edge of a battery module in the battery pack of FIG. 1, showing an aperture for receiving a bus bar;

FIG. 8 is a perspective view of the terminal shown in FIG. 7 disposed at a side edge of the battery module, showing an electrically insulative cover disposed to cover at least a portion of the bus bar when the bus bar is received by the aperture;

FIG. 9 is a perspective view of a portion of the top surface of the battery pack of FIG. 1 showing the bus bars engaged with the terminals of the battery modules and showing the battery modules supported in the battery pack by the frame;

FIG. 10 is a schematic side view of an electric vehicle including the battery pack shown in FIG. 1; and

fig. 11 is a schematic plan view of an electric vehicle including the battery pack shown in fig. 1.

Detailed Description

Examples of the present invention are described in the context of a battery pack for an electric vehicle. Those skilled in the art will recognize that these examples are not limited to this purpose. For example, the battery packs described herein may also be used to provide and store electrical energy for any type of industrial, commercial, or domestic purpose, such as for storing and delivering energy in smart grid, domestic energy storage systems, electrical load balancing, and the like applications.

In the illustrated example, the battery pack includes battery modules each including a plurality of battery cells, which are so-called prismatic batteries and are substantially cuboidal. However, in other examples, the battery module may include other forms of batteries, such as cylindrical batteries. The battery cells may be lithium-ion, lithium-ion polymer, nickel metal hydride, nickel cadmium, nickel hydride, alkaline, or other battery types/configurations. The battery cell is connected within the battery module to provide a voltage between two terminals of the battery module. The battery module is mounted on a frame within the battery pack structure.

Fig. 1 to 4 show an example of a battery pack, and fig. 5 to 9 show features of the battery pack in more detail. Fig. 10 and 11 show an electric vehicle including the illustrated example of the battery pack. The same reference numbers will be used throughout the drawings to refer to the same or like features.

Fig. 1 shows that the example of the battery pack 1 shown comprises sixteen battery modules 2a-2p, which are arranged in a first row 3a and a second row 3b of eight battery modules each. Each

row

3a, 3b is arranged from the front of the battery pack to the rear, the front being on the left and the rear being on the right, as shown.

As shown in fig. 1, the

battery modules

2a and 2i are disposed toward the front of the battery pack, and the

battery modules

2h and 2p are disposed toward the rear of the battery pack. Each battery module 2a-2p has a first end including a first terminal 4a-4p and a second end opposite the first end including a second terminal 5a-5 p. The first terminals 4a-4h of the first row 3a of battery modules 2a-2h are arranged on a first side of the row 3a and the second terminals 5a-5h of the first row 3a of battery modules 2a-2h are arranged on an opposite second side of the row 3 a. The first terminals arranged alternately along said row 3a have opposite polarity and, correspondingly, the second terminals arranged alternately along said row 3a have opposite polarity. In the example shown,

terminals

5a, 4b, 5c, 4d, 5e, 4f, 5g and 4h have a positive polarity and

terminals

4a, 5b, 4c, 5d, 4e, 5f, 4g and 5h have a negative polarity.

Similarly, for the second row 3b, the first terminals 4i-4p of the battery modules 2a-2h of the second row 3b are disposed on a first side of the second row 3b, and the second terminals 5i-5p of the battery modules 2a-2h of the second row 3b are disposed on an opposite second side of the second row 3 b. The first terminals alternately arranged along the second row 3b have opposite polarities, and correspondingly, the second terminals alternately arranged along the second row 3b have opposite polarities.

According to this example, the modules 2a-2p are arranged in a single layer. Other examples may have more than one layer of battery modules.

Fig. 2 shows the battery module 2a in more detail. The battery modules 2b-2p have similar features. As shown in the example of battery module 2a, each battery module is of generally cubic form having a first terminal 4a on a first minor face and a second terminal 5a on a second minor face 15 opposite the first minor face. The battery modules 2a are arranged such that the secondary faces are parallel to the length of the battery pack. The major dimension of the battery modules 2a is perpendicular to the corresponding row 3a of battery modules and perpendicular to the length of the battery pack. The

terminals

4a, 5a in this example extend upwardly beyond the upper surface of the battery module 2 a.

Fig. 3 shows the battery pack 1 of the illustrated example having bus bars 6a-6e, 7a-7e, 8a-8e, and 9a-9e that interconnect the terminals of the battery modules 2a-2p to provide two current paths through the battery pack. The battery modules of each

row

3a, 3b provide a current path. The two current paths may be configured in series or in parallel. Each bus bar provides a low resistance electrical connection path between the terminals of the respective battery modules. The bus bars are typically made of metal, for example, copper or aluminum. The busbars in this example are elongate and substantially planar.

As shown in fig. 3, fuses 10a, 10b are provided in the current paths through the battery modules of each

row

3a, 3 b. In the example shown, there is provided a

disconnect device

14a, 14b in series with each

fuse

10a, 10b, which may be a switch or a removable link. Other examples may have no

disconnect devices

14a, 14b other than the

fuses

10a, 10 b. The

fuses

10a, 10b and/or the

disconnection devices

14a, 14b may be referred to as current interruption devices. As described below, each bank includes two subsets of modules, four modules each, with

fuses

10a, 10b and

circuit interrupting devices

14a, 14b located between each subset in a bank. In the example shown, the first row 3a comprises a first subgroup comprising

battery modules

2c, 2d, 2g and 2h and a second subgroup comprising

battery modules

2f, 2e, 2b and 2 a. The fuse 10a is located in the current path between the first subset and the second subset. The second row 3b includes a third sub-group including the

battery modules

2i, 2j, 2m, and 2n, and a fourth sub-group including the

battery modules

2p, 2o, 2j, and 2 k. The fuse 10b is located in the current path between the third subset and the fourth subset.

The

disconnect devices

14a, 14b may be used during maintenance and repair to limit the voltage between any two points in each row of battery modules by dividing the row into two disconnected portions. In the example shown, the nominal value of the voltage between the terminals of each battery module is 50 volts, so that when the disconnection means 14a, 14b are arranged to disconnect two portions of a row, there will be a maximum value of 200 volts nominal between any two portions of the row, which allows a safer operation than if there were 400 volts.

In the example shown, the battery pack 1 includes a battery pack control circuit 13, the battery pack control circuit 13 including a battery management system controller and a battery pack reconfiguration circuit. The battery management system controller includes a processor configured to accept input from sensors (e.g., temperature and/or voltage sensors) mounted on the battery module and protect the battery pack by controlling charging and/or discharging of the battery pack to maintain operating parameters within safe limits. The battery pack reconfiguration circuit includes semiconductor and/or electromechanical switches to allow the first row of battery modules and the second row of battery modules to be configured in series or in parallel.

Fig. 3 shows the current path through the battery modules of the first row 3a with arrows (superimposed on the respective bus bars) indicating the current direction during discharge of the batteries. Current flows from the battery pack control circuit 13 to the negative terminal of the battery module 2 c; from the positive terminal of the battery module 2c to the negative terminal of the battery module 2 d; from the positive terminal of the battery module 2d to the negative terminal of the battery module 2 g; from the positive terminal of the battery module 2g to the negative terminal of the battery module 2 h; and then flows to the fuse 10 a. Then, the current flows to the negative terminal of the battery module 2f through the fuse 10 a; from the positive terminal of the battery module 2f to the negative terminal of the battery module 2 e; from the positive terminal of the battery module 2e to the negative terminal of the battery module 2 b; flows from the positive terminal of the battery terminal 2b to the negative terminal of the battery module 2 a; and then flows from the positive terminal of the battery module 2a to the battery control circuit 13.

The first row of battery modules 2a-2h (which may also be referred to as a half pack) is divided into two sub-groups (which may also be referred to as a quarter pack): a

first quarter pack

2c, 2d, 2g, 2h and a

second quarter pack

2f, 2e, 2b, 2 a. In this example, each quarter pack comprises four modules and each quarter pack has a current direction opposite to the other quarter pack of the row. This arrangement allows the current interrupt device, including the

fuse

10a, 10b and/or

disconnect device

14a, 14b between two quarter packs, to be located at the rear of the battery pack rather than between battery modules within the battery pack. By arranging the current interrupt device at the rear of the battery pack, it is easier to access the fuse and/or the disconnection device even when the module is encapsulated and/or covered in a housing or the like. This arrangement also allows the voltage generated on the two rows to be taken at the same end of the battery pack, in this case at the front of the battery pack. By taking the voltages generated on the two rows at the same end of the battery pack, the

rows

3a, 3b can be connected in series or in parallel by the battery pack reconfiguration circuit 13 without using long bus bars extending from the front to the rear of the battery pack. The use of long busbars is further avoided by arranging each quarter pack to include two pairs of adjacent modules and having the two pairs of modules separated by one pair of modules from the other quarter pack of the half pack. In contrast, arranging a quarter pack into four adjacent battery modules results in the use of longer bus bars. Longer busbars add cost, may require additional support, and may exhibit more thermal expansion problems.

If the pack reconfiguration circuit in the pack control circuit 13 is configured to connect the bus bars 7a and 8a together, the two rows of battery modules are connected as sixteen modules in series. Alternatively, if the battery pack is configured such that the bus bars 6a and 8a are connected together, and the bus bars 7a and 9a are connected together by the battery pack reconfiguration circuit, two rows each composed of eight modules are connected in parallel. In this example, each battery module has a voltage of nominally 50 volts, providing a nominal value of 800 volts in the series arrangement and a nominal value of 400 volts in the parallel arrangement, as previously described. In use, two rows of modules may be first connected in parallel to charge from a dc charger of about 400 volts and then connected in series to drive the motor from a power supply of about 800 volts, thereby improving efficiency. Alternatively, two rows of modules may be connected in series to charge from a charger of approximately 800 volts. The discharge of the battery pack may also be arranged to discharge from two parallel rows of battery modules at a nominal voltage of 400 volts. If a fault is detected in one of the rows, the battery pack may be configured to be charged and/or discharged using only one row for continued use, albeit with a reduced capacity.

Fig. 3 shows that the busbars of each

row

3a, 3b are arranged at or near the edges of each row, and that a space is provided along the middle of each row between the busbars on the top surface of the battery module, which space is not obstructed by the busbars. Considering the first row 3a, the

busbars

6a, 6b, 6c and 6d are located at or near one edge of the row 3a, and the

busbars

7a, 7b, 7c and 7d are located on the opposite side of the row 6 a. Fig. 3 shows the path across the top surface of the row 3a of battery modules 2a-2h that is unobstructed by the bus bars. A similar path is provided between the busbars of the second row 3 b. The fuse device of each row of bus bars allows them to be tightly packed together on each side of the row while providing protection in the event of a short circuit between bus bars adjacent to each other. This arrangement allows for a greater space to be provided between the busbars on each side of the row than if the busbars were further apart.

Fig. 3 shows that in the example shown at least some of the busbars of each row of

battery modules

3a, 3b are arranged in pairs. In particular, the

busbars

6c and 6d, 7b and 7c, 8b and 8c and 9d are arranged in pairs. Members of the pair of bus bars are disposed on the same side of the respective row. The bus bars in a pair are disposed in substantially parallel relationship to each other and are arranged to cross the boundary between the same two adjacent battery modules in the row. For example, as shown, bus bar 6d connects

battery modules

2e and 2f and crosses boundary 25 between

modules

2e and 2 f. The bus bar 6d is formed in a U-shape in a plane parallel to the top surface of the battery module, and has a flat central elongated section with a substantially constant width, and two end sections connected at right angles to the flat central elongated section. One end section is connected to terminal 4e of battery module 2e and the other end section is connected to terminal 4f of battery module 2 f. The bus bar 6c is also formed in a U-shape in a plane parallel to the top surface of the battery module, and the bus bar 6c also has a flat central elongated section with a substantially constant width. The straight central elongated section of the bus bar 6c is arranged side by side and parallel to the straight central elongated section of the bus bar 6 d. The busbar 6d has two end sections connected at right angles to a straight central elongate section. One end section is connected to terminal 4d of battery module 2d and the other end section is connected to terminal 4g of battery module 2 g. Thus, the busbar 6d is longer than the busbar 6c and is arranged so as not to intersect the busbar 6c, leaving a gap of substantially constant width between the straight elongated central sections of the two

busbars

6c and 6 d.

Fuses

10a, 10b are arranged in the current path between each pair of busbars. For example, a bus bar among the pair of bus bars 6a and 6b is protected by the fuse 10a, and a bus bar among the pair of

bus bars

6c and 6d is also protected by the fuse 10 a. On the other side of the row 3a, the bus bars among the paired

bus bars

7e and 7d and 7c and 7b are also protected by the fuse 10 a. This is because one bus bar of a pair connects battery modules of one sub-group (e.g., a first sub-group including

battery modules

2c, 2d, 2g, and 2 h) together, and the other bus bar of the pair connects battery modules of the other sub-group of the row (e.g., a second sub-group including

battery modules

2f, 2e, 2b, and 2 c) together. Thus, if the bus bars in a pair are accidentally shorted together, current will flow in the circuit including the fuses between the two subsets, and the fuses will blow, stopping the current flow. Similarly, in the second row, the bus bars among the paired

bus bars

8b and 8c, 8d and 8e, 9a and 9b, and 9c and 9d are protected from short-circuiting with each other by the fuse 10 b.

Fig. 3 shows that the busbars 7a-7e of the first row 3a are adjacent to the busbars 8a-8e of the second row 3 b. In particular, the

busbars

7a and 8a, 7b and 8b, 7c and 8c, 7d and 8d, and 7e and 8e are adjacent where these busbars connect with the terminals provided between the rows. In the case where the first row 3a and the second row 3b are configured to be connected in series, a voltage as shown in table 1 appears on the bus bar. If the first bank 3a and the second bank 3b are configured to be connected in parallel, a voltage as shown in table 2 appears on the bus bar.

When the first row 3a and the second row 3b are connected in series, there are bus bars of the first row 3a adjacent to bus bars of the second row 3b and protected by one or more fuses in case of a short circuit of adjacent bus bars together. For example, if adjacent 50 volt bus 7c and 750 volt bus 8c are shorted together, the resulting current will flow through

fuses

10a and 10b, and at least one fuse will blow, stopping the current. Further, if the adjacent 150 volt bus bar 7e and 650 volt bus bar 8e are short-circuited together, or if the adjacent 200 volt bus bar 7d and 600 volt bus bar 8d are short-circuited together, one or both of the

fuses

10a and 10b may be blown.

When the first row 3b and the second row 3a are in a series connected configuration, there are also bus bars of the first row 3a adjacent to the bus bars of the second row 3b and unprotected by the fuse in case of short circuit together of adjacent bus bars, for example adjacent 300 volt bus bars 7b and 500 volt bus bars 8 b. These bus bars are provided with an additional electrically insulating layer 12a, 12b compared to adjacent bus bars with a fuse arranged therebetween. The additional electrically insulating layers 12a, 12b will be described in more detail below in connection with fig. 5.

An additional electrically insulating layer 11 is provided between the

busbars

7a and 8a of the adjacent first and

second rows

3a and 3 b. The bus bar 7a is a separate bus bar that is not arranged to connect a pair of bus bars of the battery modules of the first row, and the bus bar 8a is a separate bus bar that is not arranged to connect a pair of bus bars of the battery modules of the second row. If

rows

3a and 3b are connected in a series configuration, then the two bus bars are at the same voltage, i.e., 400 volts; however, when

rows

3a and 3b are connected in a parallel configuration, bus 7a is at 400 volts and bus 8a is at 0 volts. The additional electrically insulating layer 11 between the bus bar 7a and the bus bar 8a will be explained in more detail below in connection with fig. 6.

When the first row 3a and the second row 3b are connected in series, the

fuses

10a, 10b are located at 200 volt and 600 volt points within the battery pack. In the case where there are adjacent bus bars and the voltage of one bus bar is lower than or equal to 200 volts and the voltage of the other bus bar is higher than or equal to 600 volts, these bus bars are protected by at least one fuse. In the case where there are adjacent bus bars, and one bus bar has a voltage higher than 200 volts and the other bus bar has a voltage lower than 600 volts, an additional electrical insulation member is provided between the bus bars to prevent short circuits.

Fig. 4 illustrates that the unobstructed space provided between the bus bars may be used to route components of a battery pack, such as, in the illustrated example, a wiring harness 16 of a battery management system. The wiring harness 16 is routed along the row 3a between the bus bars, which have the same reference numerals as in fig. 3. The battery management controller of the battery pack control circuit 13 located at the front of the battery pack is connected to the

sensors

17a, 17b by wiring in the wiring harness 16 of the battery management system. In this way, the wiring harness need not cross the bus bar. Crossing the bus bars may cause electrical noise and/or present an electrical safety hazard.

Fig. 5 shows an additional electrically insulating layer 12a between the

busbars

7b and 8b in the example shown. The additional electrically insulating layer is in the form of a physical barrier of insulating material comprising substantially planar walls arranged between respective terminals of the battery modules to which the bus bars are connected. As shown in fig. 5, in this example, a part of the bus bar is covered with an electrical insulating layer, but the end of the bus bar connected to the connection terminal of the module is not covered with the electrical insulating layer.

Fig. 6 shows more details of the additional electrically insulating layer 11 provided between the

busbars

7a and 8a in the example shown. The additional electrically insulating layer 11 is in the form of a physical barrier of insulating material, comprising an insulating tray carrying the electrical components of the battery pack, which insulating tray provides a barrier of electrically insulating material between adjacent bus bars. The supports (not shown) of the tray are arranged between the respective terminals of the

battery modules

2a, 2i to which the bus bars are connected. The support of the tray provides an insulating wall between the

busbars

7a and 8 a. In an alternative example, the additional electrically insulating layer between the bus bars 7a and 8a may comprise substantially planar walls arranged between the respective terminals of the battery modules to which the bus bars are connected, in a configuration similar to that shown in fig. 5. It should be understood that additional electrically insulating layers in the form of physical barriers or walls of insulating material may be provided at any location within the battery pack where a short circuit may occur.

Fig. 7, 8 and 9 show perspective views of the terminals 4a of the battery module 2a, the terminals 4a being representative examples of the terminals 4a-4p and 5a-5p in the first and second examples. The terminal 4a is also referred to as a terminal connector 4 a. As can be seen from the figure, the terminals 4a extend upward beyond the upper surface of the battery module 2 a. Fig. 9 shows that the

bus bars

6d, 7b are elongated inter-module connectors of a substantially planar shape, which are connected to the

respective terminals

4e, 4f and which penetrate the upper surface of the battery module. It can be seen that the terminals of each battery module are disposed closer to the first side of the row and farther from the other side of the row at the side edges of the respective battery module.

Fig. 7, 8 and 9 also show that each terminal 4a, 4e, 4f, 5e has an aperture 21, the aperture 21 being substantially aligned with the upper surface of the respective battery module and configured to receive the

bus bar

6d, 7 b. Each terminal has an electrically insulating cover 19, the electrically insulating cover 19 being arranged to cover at least a portion of the busbar adjacent the aperture.

In the example shown, each terminal 4a, 4e, 4f, 5e protrudes from a side edge of the

respective battery module

2a, 2f, 2e, and the aperture 21 faces the respective battery module. The terminals have a substantially rectangular cross-section in the plane of the top surface of the respective battery module. The aperture 21 for receiving the bus bar is located at or slightly above the top edge of the module so that the bus bar can be disposed along the top surface of the module. The electrically insulating cover 19, which may be referred to as a cap, extends over the bus bar portion not covered by the electrically insulating layer to the insulating portion, which provides electrical safety during assembly and maintenance.

Fig. 9 shows that the

battery modules

2e, 2f are supported in the battery pack by the frame 22.

Fig. 10 and 11 show schematic side views and schematic plan views of an electric vehicle 23 having a battery pack 1 according to the illustrated example. The battery pack 1 is mounted under the vehicle 23 for ease of maintenance and provides a lower center of mass to improve stability when the vehicle is turning.

The above examples are to be understood as illustrative examples of the invention.

Other examples of the invention are also contemplated, for example, a single row of battery modules may be provided, or more than two rows of battery modules may be provided. More or less than 8 modules in a row may be provided and various nominal voltages may be provided at the terminals of the battery modules. For example, a nominal voltage of 25 volts or other voltage may be provided. Depending on the state of charge of the battery module, the actual voltage provided by the battery module may differ from the nominal voltage when in use. In other examples, the battery modules may have a different shape than in the examples, e.g., the battery modules may not have a major dimension perpendicular to a respective row of battery modules. For example, the battery modules may be shaped such that the major dimension is parallel to the row of battery modules, and the terminals may not be located on the minor faces of the battery modules.

It is to be understood that any feature described in association with any one example may be used alone, or in combination with other features described, and may also be used in combination with one or more features of any other example, or any combination of any other example. Furthermore, equivalents and modifications not described above may also be employed without departing from the scope of the invention, which is defined in the accompanying claims.

Claims

1. A battery pack, comprising:

a first battery module and a second battery module arranged side by side in a battery pack; and

an inter-module connector connecting the first battery module and the second battery module,

wherein each battery module has terminals extending upward beyond an upper surface of the battery module, and

the inter-module connectors are connected to the respective terminals and extend through the respective upper surfaces of the first and second battery modules,

the battery pack includes a plurality of battery modules including a first battery module and a second battery module, the plurality of battery modules being arranged in a row along a length of the battery pack, and

wherein the row of battery modules is arranged from the front to the rear of the battery pack,

the plurality of battery modules are configured such that, in use, current flows along a current path from the front to the rear of the battery pack through a first subset of the modules in the row and from the rear to the front of the battery pack through a second subset of the modules in the row, wherein at least one module of the second subset is located between at least two modules of the first subset.

2. The battery pack according to claim 1, wherein each terminal is disposed at a side edge of the corresponding battery module.

3. The battery pack of claim 1 or 2, wherein the plurality of battery modules are arranged as pairs of adjacent modules along the row, the modules of each pair being electrically connected together directly in series.

4. A battery pack according to any of the preceding claims, wherein the first sub-group of modules is connected to the second sub-group of modules by means of a current interrupt feature at the rear of the battery pack.

5. The battery pack according to claim 4, wherein the current interrupting device comprises a fuse.

6. A battery pack, as claimed in claim 4 or 5, wherein the current interruption means comprises a switch.

7. A battery pack, as recited in any of the preceding claims, wherein the battery modules in the row are arranged such that adjacent battery modules in the row have terminals of opposite polarity on the first side of the row.

8. The battery pack of any one of the preceding claims, comprising a further plurality of battery modules arranged in a further row from the front to the rear of the battery pack,

wherein the further plurality of modules are configured such that, in use, current flows along a further current path from the front to the rear of the battery pack through the third sub-group of the further plurality of battery modules and from the rear to the front of the battery pack through the fourth sub-group of the further plurality of battery modules,

wherein at least one module of the fourth subset is located between at least two modules of the third subset.

9. The battery pack according to claim 8, wherein the one row and the other row have the same overall arrangement of battery modules.

10. A battery pack as claimed in claim 8 or 9, wherein the battery pack is switchable between a first configuration in which the plurality of battery modules are connected in series with the further plurality of battery modules and a second configuration in which the plurality of battery modules are connected in parallel with the further plurality of battery modules.

11. A battery pack, as recited in any of the preceding claims, wherein the inter-module connectors are substantially planar elongated bus bars.

12. The battery pack of claim 11, wherein each terminal has an aperture substantially aligned with an upper surface of a respective battery module, the aperture configured to receive a bus bar.

13. The battery pack of claim 12, wherein each terminal has an electrically insulating cover arranged to cover at least a portion of the bus bar adjacent the aperture.

14. The battery pack of claim 12 or 13, wherein each terminal protrudes from a side edge of the respective module, and the aperture faces the respective battery module.

15. A battery pack, as recited in any of the preceding claims, wherein the terminals have a substantially rectangular cross-section in the plane of the top surface of the respective battery module.

16. An electric vehicle comprising a battery pack as claimed in any preceding claim.