High-voltage circuit with multi-branch power batteries connected in parallel and used for electric heavy commercial vehicle

Abstract

The invention discloses a multi-branch power battery parallel high-voltage circuit for an electric heavy commercial vehicle, which comprises a battery system BT1, a battery system BT2, a battery system BT3, a fuse F1, a fuse F2, a fuse F3 and a high-voltage box H1, and is characterized in that the high-voltage box H1 comprises a battery management system BMS, a relay S1, a relay S2, a relay S3 and a current sensor MT1; the positive electrode of the battery system BT1 is connected with the relay S1 through the fuse F1, and the positive electrode of the battery system BT2 is connected with the relay S2 through the fuse F2. By means of the scheme, when multiple branch battery systems of a new energy commercial vehicle are used in parallel, automatic control can be achieved through a BMS, and potential safety hazards caused by manual operation are avoided; and when an internal short circuit or thermal runaway occurs in a certain branch, a fault source can be independently disconnected, so that the risk is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of electric vehicles, and particularly to a high-voltage circuit for parallel connection of multi-branch power batteries for electric heavy commercial vehicles. Background Art

[0002] Since the overall vehicle and load capacity of electric heavy commercial vehicles are large, the energy required for the batteries is also more than that of ordinary electric passenger vehicles; generally, the power battery capacity of ordinary electric passenger vehicles is below 100 kWh, while the power battery capacity of electric commercial vehicles is generally about 300 - 400 kWh, or even higher.

[0003] Therefore, most of the electric heavy commercial vehicles on the market currently adopt the method of parallel connection of multi-branch battery systems to supply power together to provide energy for the vehicle's power consumption end.

[0004] As Figure 1 shown: BT1, BT2, and BT3 are respectively battery systems of three branches. These power batteries are all composed of the same type of battery cells with the same number of series combinations, thus forming three sets of power battery systems with basically the same total voltage; F1, F2, and F3 are respectively fuses for each loop, which play the role of separately protecting each branch battery system; H1 is a high-voltage box, which contains a battery management system BMS, a relay S1, a relay S2, and a current sensor MT1; The battery systems of the three branches BT1, BT2, and BT3 are connected to H1 through connectors. The positive electrodes of the battery systems of the three branches are joined together at point A and then connected to the S1 relay; the negative electrodes of the battery systems of the three branches are joined together at point B, then pass through the MT1 current sensor and are connected to S2; after the battery systems of the three branches are paralleled in the high-voltage box H1, the BMS controls the closing of S1 and S2 respectively, and then OUT+ and OUT- can be output to provide electrical energy for the vehicle's power consumption end.

[0005] The parallel connection of the battery systems of the three branches has been completed in advance at points A and B of the H1 high-voltage box. When assembling the batteries, it is manual operation to connect 6 connectors successively to complete the parallel connection of the three branches; because the self-discharge of each set of batteries is different and the production dates are different, although they are the same type of battery cells and the number of series is the same, there will still be differences in the total voltage. This difference will cause loop current when manually paralleling the batteries; if the voltage difference is too large, it will cause too large current and generate arc phenomenon, posing potential hazards such as burns to the operators.

[0006] Moreover, if a single-branch battery system in the three branches fails, such as internal short circuit or thermal runaway, the BMS cannot disconnect the connection between the other two-branch battery systems and it, which will cause more serious safety accidents. Summary of the Invention

[0007] In order to make up for the deficiencies of the prior art, the embodiment of the present application proposes a high-voltage circuit for parallel connection of multi-branch power batteries for electric heavy commercial vehicles to solve the problems existing in the prior art.

[0008] In order to solve the above technical problems, the present invention provides the following technical solutions: A high-voltage circuit for parallel connection of multi-branch power batteries for electric heavy commercial vehicles includes a battery system BT1, a battery system BT2, a battery system BT3, a fuse F1, a fuse F2, a fuse F3, and a high-voltage box H1. The high-voltage box H1 includes a battery management system BMS, a relay S1, a relay S2, a relay S3, and a current sensor MT1. The positive electrode of the battery system BT1 is connected to the relay S1 through the fuse F1, the positive electrode of the battery system BT2 is connected to the relay S2 through the fuse F2, the positive electrode of the battery system BT3 is connected to the output OUT+ through the fuse F3. The other end of the relay S1 is connected to the output OUT+, the other end of the relay S2 is connected to the output OUT+. After the negative electrodes of the battery system BT1, the battery system BT2, and the battery system BT3 are connected in parallel, they are connected to the relay S3 through the current sensor MT1, and the other end of the relay S3 is connected to the output OUT-.

[0009] As a further technical solution of the present invention: The battery systems BT1, BT2, and BT3 are all composed of the same type of battery cells and the same number of series combinations.

[0010] As a further technical solution of the present invention: The relay S1 is a normally open contact relay.

[0011] As a further technical solution of the present invention: The relay S2 is a normally open contact relay.

[0012] As a further technical solution of the present invention: The relay S3 is a normally open contact relay.

[0013] One or more technical solutions provided in the embodiment of the present application have at least the following technical effects or advantages: By adopting the solution of the present invention, when multi-branch battery systems are used in parallel for new energy commercial vehicles, through the automatic control of the BMS, the safety hazards brought by manual operation can be avoided; and when an internal short circuit or thermal runaway occurs in a certain branch, the fault source can be disconnected separately, thereby reducing the risk. Description of the Drawings

[0014] Figure 1 It is a circuit diagram of the prior art.

[0015] Figure 2This is the circuit diagram of the present invention. Detailed implementation mode

[0016] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0017] A high-voltage circuit for parallel connection of multi-branch power batteries for electric heavy commercial vehicles, as Figure 2 shown, BT1, BT2, and BT3 are battery systems of three branches respectively. These power batteries are all composed of the same type of battery cells and the same number of series combinations, thus forming three sets of power battery systems with basically the same total voltage; F1, F2, and F3 are fuses for each loop respectively, which play the role of separately protecting the battery systems of each branch; H1 is a high-voltage box, which contains a battery management system BMS, a relay S1, a relay S2, a relay S3, and a current sensor MT1; The battery systems of the three branches of BT1, BT2, and BT3 are connected to H1 through connectors. Among them, the positive pole of BT1 is connected to the relay S1, and the positive pole of BT2 is connected to the relay S2; after the negative poles of the battery systems of the three branches are joined together at point B, they pass through the MT1 current sensor and then are connected to S3; after the BMS controls S1 and S2 to close, the positive poles of the battery systems of the three branches are paralleled at point A. After the BMS controls S3 to close, the battery systems of the three branches are completed in parallel, and then OUT+ and OUT- can be output to provide electrical energy for the vehicle's power consumption end.

[0018] Since the battery parallel connection is carried out through the BMS, when manual operation of the connectors is performed, there will be no safety risk due to large battery voltage differences. If the voltage difference is too large, the BMS can also detect it, give an alarm, and do not perform the operation of closing the relay, thus ensuring the safety of the whole vehicle; if the BMS detects that any branch has a fault, it can also separately cut off the relay of that branch, thus avoiding greater potential safety hazards.

[0019] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, it is intended to include all changes falling within the meaning and scope of the equivalent elements of the claims in the present invention.

[0020] In addition, it should be understood that although this specification is described in terms of embodiments, not every embodiment contains only one independent technical solution. This narrative manner of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment have been appropriately combined to form other embodiments that are easily understood by those skilled in the art.

Claims

1. A high-voltage circuit for multi-branch power batteries in parallel for electric heavy-duty commercial vehicles, comprising a battery system BT1, a battery system BT2, a battery system BT3, a fuse F1, a fuse F2, a fuse F3 and a high-voltage box H1, wherein the high-voltage box H1 comprises a battery management system BMS, a relay S1, a relay S2, a relay S3, and a current sensor MT1, characterized in that: The positive pole of the battery system BT1 is connected to the relay S1 through the fuse F1, the positive pole of the battery system BT2 is connected to the relay S2 through the fuse F2, the positive pole of the battery system BT3 is connected to the output OUT+ through the fuse F3, the other end of the relay S1 is connected to the output OUT+, and the other end of the relay S2 is connected to the output OUT+. The negative poles of the battery systems BT1, BT2, and BT3 are connected in parallel and then connected to the relay S3 through the current sensor MT1. The other end of the relay S3 is connected to the output OUT-.

2. The high-voltage circuit of multi-branch power battery parallel connection for electric heavy-duty commercial vehicles according to claim 1 is characterized in that: The battery system BT1, the battery system BT2, and the battery system BT3 are all composed of the same type of battery cells and the same number of series connections.

3. The high-voltage circuit of multi-branch power battery parallel connection for electric heavy-duty commercial vehicles according to claim 1, characterized in that: The relay S1 is a normally open contact relay.

4. The high-voltage circuit of multi-branch power battery parallel connection for electric heavy-duty commercial vehicles according to claim 1, characterized in that: The relay S2 is a normally open contact relay.

5. The high-voltage circuit of multi-branch power battery parallel connection for electric heavy-duty commercial vehicles according to claim 1, characterized in that: The relay S3 is a normally open contact relay.

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