Battery monomer and battery pack

Abstract

The utility model belongs to the technical field of secondary batteries, and particularly provides a battery monomer and a battery pack. The single battery comprises a shell and an end cover, a pressure relief hole is formed in the bottom wall of the shell, an anti-explosion valve is connected to the pressure relief hole, a fire extinguishing component connected with the bottom wall is further arranged in the shell, and the fire extinguishing component comprises a shell which can be broken when the temperature reaches or exceeds the set temperature and a fire extinguishing agent located in the shell. The battery pack comprises the battery monomer. The fire extinguishing component positioned at the bottom of the battery monomer can play the same fire extinguishing role, and meanwhile, when corresponding conducting strips and conducting bars need to be welded on the pole columns, the fire extinguishing component is not influenced by welding high temperature, so that the shell of the fire extinguishing component is prevented from being broken, the production process is controllable, and the qualified rate of products is improved. In addition, the high-temperature flue gas can be discharged outwards from the flue gas flow channel at the bottom of the box body, so that the high-temperature flue gas is prevented from damaging other electric appliance elements in the battery pack.

Description

Technical Field

[0001] This utility model belongs to the field of secondary battery technology, and in particular relates to a battery cell and a battery pack. Background Technology

[0002] During charging and discharging (e.g., overcharging, short circuits) or when subjected to mechanical damage, the internal temperature of a single battery cell can rise abnormally for a short period, accelerating internal chemical reactions and causing the explosion-proof valve to rupture, potentially leading to battery fire or explosion. Currently, common methods for preventing these thermal runaway problems include the following:

[0003] One approach is to use thermal insulation layers or pads between battery cells to block heat conduction from thermally runaway cells to adjacent receiver cells. However, this method has limited effectiveness when multiple battery cells run away simultaneously.

[0004] Secondly, heat can be dissipated using a liquid cooling system inside the battery pack. However, in reality, the thermal conductivity of liquid cooling systems is limited, and their main function is to maintain the battery at a temperature that allows for high charge and discharge efficiency.

[0005] Thirdly, corresponding control programs are set in the vehicle's BMS (Battery Management System) to cut off the battery pack power in the event of thermal runaway. However, the battery pack itself is charged, and there is still a risk of combustion after the power is cut off.

[0006] Fourthly, the explosion-proof valves on individual battery cells and the corresponding locations on wiring harness assemblies are weakened to make it easier for the fumes generated by battery heating to escape. However, this does not extinguish the fire.

[0007] A search revealed that a utility model patent with authorization announcement number CN220544160U discloses a battery cell. The outer shell of the battery cell includes a wall portion (i.e., an end cap) with a pressure relief hole. The pressure relief hole is provided on the wall portion, and an explosion-proof valve covering the pressure relief hole is provided at the pressure relief hole. Inside the battery cell, there is also a protective diaphragm (i.e., a fire extinguishing component) located inside the explosion-proof valve. The protective diaphragm also covers the pressure relief hole. It includes an outer thin film and a fire extinguishing agent located inside the outer thin film. After the outer thin film ruptures, the fire extinguishing agent can be released to reduce the risk of thermal runaway of the battery cell.

[0008] The aforementioned patent discloses a method for installing a fire extinguishing component inside a battery cell. Specifically, both the explosion-proof valve and the fire extinguishing component are located at the top of the battery cell (i.e., at the end cap). More specifically, both the explosion-proof valve and the fire extinguishing component are located between the positive and negative terminals. This solution still has the following problems: First, the fire extinguishing component is a heat-sensitive component. When battery cells are connected in series / parallel, multiple welding processes, such as welding conductive busbars and adapter plates, are required. The high temperature generated during welding may cause the fire extinguishing component to react, leading to leakage of the extinguishing agent and affecting the product qualification rate. Second, after the explosion-proof valve is opened, the emitted high-temperature fumes will directly accumulate on the top of the battery cell. This location usually contains wiring harnesses and other related electrical components, and the high-temperature fumes can easily damage these components. Utility Model Content

[0009] The purpose of this invention is to provide a battery cell that solves the technical problems of low product yield and easy damage to electrical components caused by the placement of fire extinguishing components and explosion-proof valves at the top of the battery cell in the prior art. Another purpose of this invention is to provide a battery pack that solves the same technical problems.

[0010] To achieve the above objectives, the technical solution for the battery cell provided by this utility model is as follows:

[0011] A battery cell includes a housing and an end cap. The bottom wall of the housing is provided with a pressure relief hole, and an explosion-proof valve is connected to the pressure relief hole. The housing is also provided with a fire extinguishing component connected to the bottom wall. The fire extinguishing component includes a shell that can be broken when a set temperature is reached or exceeded, and a fire extinguishing agent located inside the shell.

[0012] As a further improvement, in the vertical projection, the area of ​​the fire extinguishing component is larger than the area of ​​the pressure relief hole.

[0013] As a further improvement, the fire extinguishing components cover the bottom wall of the casing.

[0014] As a further improvement, the fire extinguishing components are bonded to the bottom wall of the casing.

[0015] This invention relates to a modification of key elements, and its beneficial effects are as follows: Compared with the prior art, the battery cell in this invention changes the positions of the explosion-proof valve and the fire extinguishing component. Specifically, both the explosion-proof valve and the fire extinguishing component are located at the bottom of the battery cell, placing the fire extinguishing component on the side opposite to the terminal post. The high temperatures generated during the welding process of assembling the battery pack will not affect the fire extinguishing component, thus preventing leakage caused by high welding temperatures and ensuring product qualification rate. Simultaneously, the high-temperature fumes emitted after the explosion-proof valve opens will not accumulate on the top of the battery pack, thereby preventing damage to other electrical components inside the battery pack from the high-temperature fumes.

[0016] To achieve the above objectives, the technical solution for the battery pack provided by this utility model is as follows:

[0017] A battery pack includes a housing and a plurality of battery cells arranged in a predetermined manner and electrically connected inside the housing. Each battery cell includes a shell and an end cap. The bottom wall of the shell has a pressure relief hole, and an explosion-proof valve is connected to the pressure relief hole. The interior of the shell also has a fire extinguishing component connected to the bottom wall. The fire extinguishing component includes a shell that can be broken when a set temperature is reached or exceeded, and a fire extinguishing agent located inside the shell. The lower wall of the housing has a flue gas passage communicating with the pressure relief hole, and the flue gas passage has an outlet for exhausting flue gas.

[0018] As a further improvement, in the vertical projection, the area of ​​the fire extinguishing component is larger than the area of ​​the pressure relief hole.

[0019] As a further improvement, the fire extinguishing components cover the bottom wall of the casing.

[0020] As a further improvement, the lower wall of the enclosure is a liquid-cooled enclosure wall with a liquid-cooled flow channel, and the liquid-cooled flow channel and the flue gas flow channel do not interfere with each other.

[0021] As a further improvement, the fire extinguishing components are bonded to the bottom wall of the casing.

[0022] This utility model is an improved invention, and its beneficial effects are as follows: Compared with the prior art, the battery cell in this utility model changes the positions of the explosion-proof valve and the fire extinguishing component, and correspondingly, a flue gas passage is added to the lower wall of the casing. Specifically, the explosion-proof valve and the fire extinguishing component are both located at the bottom of the battery cell, so that the fire extinguishing component is located on the side away from the terminal post. The high temperature generated during the welding process of assembling the battery pack will not affect the fire extinguishing component, thus avoiding leakage of the fire extinguishing component caused by the high temperature of welding, thereby ensuring the product qualification rate. At the same time, the high-temperature flue gas ejected after the explosion-proof valve is opened can be discharged outward through the flue gas passage, thus also preventing the high-temperature flue gas from damaging other electrical components inside the battery pack. Attached Figure Description

[0023] Figure 1 This is a structural schematic diagram (perspective view) of a battery cell embodiment of the present invention.

[0024] Figure 2 This is a cross-sectional view of an embodiment of the battery cell in this utility model;

[0025] Figure 3 This is a three-dimensional axonometric view of the housing (lower housing) in the battery pack embodiment of this utility model;

[0026] Figure 4 This is a top view of the housing (lower housing) in the battery pack embodiment of this utility model;

[0027] Figure 5 This is a bottom view of the housing (lower housing) in the battery pack embodiment of this utility model;

[0028] Figure 6 This is a diagram showing the arrangement of the flue gas flow channel and liquid cooling flow channel inside the battery pack embodiment of this utility model.

[0029] Explanation of reference numerals in the attached figures:

[0030] 1. Battery cell; 2. Housing; 101. End cap; 102. Positive terminal; 103. Negative terminal; 104. Shell; 105. Explosion-proof valve; 106. Fire extinguishing components; 107. Battery cell; 201. Coolant inlet; 202. Coolant outlet; 203. Flue gas flow channel; 204. Flue gas outlet; 206. Liquid cooling flow channel. Detailed Implementation

[0031] Adding fire extinguishing components (fire protection packs) inside individual battery cells can reduce the risk of fire caused by thermal runaway. Since explosion-proof valves are generally located on top of battery cells, existing technology also places the fire extinguishing components on top of the battery cells, constrained by this conventional thinking. However, during the subsequent assembly of multiple battery cells into a battery pack, the high temperatures generated during welding can easily cause the fire extinguishing components to rupture, leading to extinguishing agent leakage. Clearly, such products are substandard. Furthermore, the high-temperature fumes ejected from the explosion-proof valves can accumulate on the top of the battery pack (inside), potentially damaging wiring harnesses and other electrical components.

[0032] To address the aforementioned problems, the basic technical concept of this utility model is to modify the structure of the battery cell. Specifically, the explosion-proof valve and fire extinguishing component are located at the bottom of the battery cell. This ensures that the fire extinguishing component is kept as far away as possible from the welding point during subsequent welding processes, preventing it from cracking due to the high welding temperatures, thereby improving the product yield. Furthermore, the high-temperature fumes are emitted from the bottom of the battery cell, preventing damage to the electrical components at the top of the battery pack. The following detailed description of this utility model, in conjunction with embodiments, further illustrates this utility model.

[0033] Specific embodiments of the battery pack provided by this utility model:

[0034] In essence, the battery pack in this embodiment includes a housing and multiple battery cells located inside the housing. The housing is composed of two parts: an upper housing and a lower housing. The cavity formed by the upper and lower housings is used to arrange battery cells, wiring harnesses, connectors, etc. The structure of the lower housing is as follows: Figures 3-5As shown. When assembling into a battery pack, multiple battery cells are arranged and electrically connected in a predetermined manner. The number of battery cells and the conductive connection method (series, parallel, or mixed) are not specifically limited in this embodiment. According to the design requirements for voltage, current, capacity, etc., those skilled in the art can adapt the number of battery cells and the conductive connection method accordingly.

[0035] When there are many individual battery cells in the battery pack, the individual cells can be connected to form a battery assembly, and then the battery assembly can be arranged in the casing, such as... Figure 3 The housing 2 shown is suitable for situations where three rows of battery packs are installed. To secure the battery cells together, adjacent battery cells can be glued together and / or bound together using straps.

[0036] Similarly, for individual battery cells, the principle is basically consistent with existing technologies, such as... Figure 1 and Figure 2 As shown, it includes a housing 104, an end cap 101, and terminals, etc. The housing 104 contains a battery cell 107, electrolyte, etc. There are two terminals, namely a positive terminal 102 and a negative terminal 103. The charging and discharging principle of the battery cell 1 will not be described in detail here.

[0037] To facilitate understanding of the technical solutions described below, it should be noted that, for a single battery cell, those skilled in the art will understand that the end of the battery cell with the terminal post is the top end and the other end is the bottom end, and the vertical direction refers to the extension direction from the top end to the bottom end.

[0038] Unlike existing technologies, such as Figure 1 and Figure 2 As shown, in this embodiment, a pressure relief hole is provided on the bottom wall of the housing 104, and an explosion-proof valve 105 is connected to the pressure relief hole. When the internal pressure of the housing 104 is too high, the explosion-proof valve 105 can open, and the high-temperature flue gas can be released from the pressure relief hole. A fire extinguishing component 106 is also provided inside the housing 104. The fire extinguishing component 106 includes an outer shell and a fire extinguishing agent located inside the outer shell. The outer shell can rupture when it reaches or exceeds a set temperature, allowing the fire extinguishing agent to flow out, thereby achieving the effect of fire extinguishing and flame retardant.

[0039] Specifically, the outer shell also needs to have a certain pressure resistance, and PP or PE materials that can melt at or above 110°C can be selected. The extinguishing agent can be a material consistent with existing technology (such as the flame retardant in the cited patent in the background art). The extinguishing agent flowing out from the crack in the outer shell can react at high temperature to produce an aerosol, which absorbs heat and oxygen to achieve the effect of flame retardant extinguishing.

[0040] Accordingly, such as Figure 3As shown, the lower wall (i.e., bottom wall) of the housing 2 is provided with a flue gas passage 203, which is connected to the pressure relief hole of the battery cell 1. The flue gas passage 203 has an outlet for discharging flue gas, namely a flue gas outlet 204. The high-temperature flue gas ejected from the pressure relief hole can enter the flue gas passage 203 and be discharged from the flue gas outlet 204.

[0041] Analysis of the above structure shows that the fire extinguishing component 106 located at the bottom of the battery cell 1 can achieve the same fire extinguishing effect. Furthermore, when welding corresponding conductive plates and conductors to the terminals, the high welding temperature will not affect the fire extinguishing component 106, thus preventing the outer casing of the fire extinguishing component 106 from cracking. This makes the production process controllable and improves the product qualification rate. In addition, high-temperature fumes can be discharged outwards from the flue gas duct 203 at the bottom of the housing 2, preventing the high-temperature fumes from damaging other electrical components inside the battery pack.

[0042] The size of the fire extinguishing component 106 can be basically the same as the size of the pressure relief hole. However, as a preferred embodiment, the fire extinguishing component can be enlarged so that, in the vertical projection, the area of ​​the fire extinguishing component 106 is larger than the area of ​​the pressure relief hole, meaning that the fire extinguishing component 106 completely covers the pressure relief hole. This prevents high-temperature smoke from ejecting the fire extinguishing component 106 from the pressure relief hole, ensuring its fire extinguishing effect.

[0043] As an optimal embodiment, the fire extinguishing component 106 covers the bottom wall of the housing 104, thus making full use of the bottom wall space to place a larger fire extinguishing component 106, which naturally has a better fire extinguishing effect.

[0044] To achieve better fixation of the fire extinguishing component 106, in a preferred embodiment, the fire extinguishing component 106 can be bonded to the bottom wall of the housing 104. However, in other embodiments, it is not excluded that the fire extinguishing component 106 is not bonded, but rather that the fire extinguishing component 106 is tightly pressed against the bottom wall of the housing 104 under the pressure of the battery cell 107.

[0045] It should be noted that, as Figures 3-6 As shown, in this case involving three rows of battery packs, the flue gas duct 203 is provided in three rows. However, adjacent flue gas ducts 203 can be connected. In fact, among the three rows of flue gas ducts 203, two adjacent flue gas ducts 203 can be connected, and different flue gas ducts 203 can share the flue gas outlet 204.

[0046] Specifically, the lower wall of housing 2 can be a sandwich structure consisting of upper and lower panels and a middle partition. The space enclosed by the panels and the middle partition forms a flue gas passage. To ensure that the flue gas passage and the pressure relief hole are connected, through holes need to be provided at corresponding positions in the upper panel. Alternatively, the lower wall can be a thicker plate with grooves cut into it to form a flue gas passage.

[0047] In some projects, the battery pack requires liquid cooling. As a preferred embodiment, the lower wall of the housing 2 is a liquid-cooled housing wall with liquid cooling channels, such as... Figures 3-5 As shown, the wall of the liquid cooling tank has a coolant inlet 201 and a coolant outlet 202. A liquid cooling flow channel arranged in a set manner is connected between the coolant inlet 201 and the coolant outlet 202. After the coolant enters from the coolant inlet 201, it flows along the liquid cooling flow channel and is discharged from the coolant outlet 202, completing the cooling cycle.

[0048] When a liquid-cooled flow channel is provided, the flue gas flow channel 203 must be designed to ensure that it does not interfere with the liquid-cooled flow channel. Specifically, for the lower chamber wall of the sandwich structure, a baffle can be installed to separate the flue gas flow channel 203 and the liquid-cooled flow channel 206 according to the actual exhaust requirements and the location of the liquid-cooled flow channel. Figure 6 As shown, the coolant inlet 201 and coolant outlet 202 are at one end of the housing 2, and the flue gas outlet 204 is at the other end of the housing 2. The liquid cooling channel 204 can bypass the flue gas channel 203 and cover the bottom wall of the housing 2.

[0049] Specific embodiments of the battery cell in this utility model:

[0050] The embodiments of the battery cells are the same as those described in the embodiments of the battery pack above, and will not be described in detail here.

[0051] Finally, it should be noted that the above description is only a preferred embodiment of this utility model and is not intended to limit this utility model. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still make modifications to the technical solutions described in the foregoing embodiments without creative effort, or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A battery cell, characterized in that, It includes a housing and end caps. The bottom wall of the housing is provided with a pressure relief hole, and an explosion-proof valve is connected to the pressure relief hole. The interior of the housing is also provided with a fire extinguishing component connected to the bottom wall. The fire extinguishing component includes a shell that can be broken when the set temperature is reached or exceeded, and a fire extinguishing agent located inside the shell.

2. The battery cell according to claim 1, characterized in that, In the vertical projection, the area of ​​the fire extinguishing component is larger than the area of ​​the pressure relief hole.

3. The battery cell according to claim 2, characterized in that, The fire extinguishing components cover the bottom wall of the casing.

4. The battery cell according to any one of claims 1-3, characterized in that, The fire extinguishing components are bonded to the bottom wall of the casing.

5. A battery pack, comprising a housing and a plurality of battery cells arranged in a predetermined manner and electrically connected within the housing, characterized in that, The battery cell includes a casing and an end cap. The bottom wall of the casing is provided with a pressure relief hole, and an explosion-proof valve is connected to the pressure relief hole. The casing is also provided with a fire extinguishing component connected to the bottom wall. The fire extinguishing component includes a shell that can be broken when the set temperature is reached or exceeded, and a fire extinguishing agent located inside the shell. The lower wall of the box is provided with a flue gas passage that communicates with the pressure relief hole. The flue gas passage has an outlet for exhausting flue gas.

6. The battery pack according to claim 5, characterized in that, In the vertical projection, the area of ​​the fire extinguishing component is larger than the area of ​​the pressure relief hole.

7. The battery pack according to claim 6, characterized in that, The fire extinguishing components cover the bottom wall of the casing.

8. The battery pack according to any one of claims 5-7, characterized in that, The lower wall of the enclosure is a liquid-cooled enclosure wall with a liquid-cooled flow channel, and the liquid-cooled flow channel and the flue gas flow channel do not interfere with each other.

9. The battery pack according to any one of claims 5-7, characterized in that, The fire extinguishing components are bonded to the bottom wall of the casing.

Images